On 08/13/2008 10:30, ak2b posted:
I plan to post some pictures and audio of my on-going construction project that includes several components of the QRP community. My transceiver consists of the NorCalQrp FCC-1/2 DDS, W7ZOI's HYCAS IF/AGC board and the rest made up of boards from the RF-ToolKits. I also swiped a few circuits from the MultiPig+. At this point I have a working transceiver with 2 bands (20 and 17 meters) and have boards for 15 and 10 that are not installed. (I need to find some way to switch them.)
Leonard, KC0WOX has posted some great videos on his website that I have found extremely helpful.
http://golddredgervideo.com/kitsandparts/
I look forward to any contributions from the rest of you. I find these little boards fascinating. Like a lot of hams, I have the need to build. I don't always know what I'm doing but I do it anyway :-).

Tom, ak2b
=====================================================================================================
On 08/13/2008 19:32, ak2b posted:
Here is a photo of my first working receiver and layout
The board labeled IF AGC should read audio agc which can be found here
http://www.partsandkits.com/potluck/view.php?id=5
[img]http://tomnyc.no-ip.org/images/erectorlayout.jpg[/img]
=====================================================================================================
On 08/13/2008 19:39, ak2b posted:
This is the first recording of the above receiver

http://tomnyc.no-ip.org/erectorrx_LZ1RGM.wav
=====================================================================================================
On 08/14/2008 18:07, kc0wox posted:
They look great! I'm looking forward to getting back to working on mine.
Leonard
=====================================================================================================
On 08/14/2008 19:55, ak2b posted:
Leonard, I can't wait to see the final episode, "Part 3 Testing the Linear" of "Building the Kits and Parts 10 watt linear". Mine is already done and I would like to see what your power output is accross the different bands.

Tom, ak2b
=====================================================================================================
On 08/16/2008 14:52, ak2b posted:
Here is back view with the 10W linear amplifier

[img]http://tomnyc.no-ip.org/images/backviewwithamps.jpg[/img]
=====================================================================================================
On 08/17/2008 10:07, ak2b posted:
Adding the 10 watt linear amplifier brought up two problems. The first was how do I split the output of the DDS into two 50 ohm signals? I found the solution to that problem at http://www.qrp.pops.net/swl-ant-split.asp. I used FT-37-43 cores. I need the output of one side to be +7dbm for the receiver and +1dbm for the transmitter. With the splitter I could easily get +7dbm for the receiver but didnít know quite how to combine the RF plus 8 volts for J1 pin 1 of the 10 watt amplifier. I tried a .1mfd cap to isolate the TX side of the splitter but when I combined it with the 8 volts for TX it just stayed at 8 volts no matter what. Clearly I had no idea what I was doing. At that point I decided on another route and that was to skip J1 on the amplifier for RF (8 volts TX was left on J1 pin 1) and feed the DDS TX RF directly into C29. One end of D5 and one end of R30 go directly to C29 so I cut both traces and put a wire jumper between the two (C29 and D5). I still needed to drop the TX RF down to +1dbm. A lot of unnecessary things took place that I wonít go into; before I remembered that the *KX1 uses a DDS VFO. I wondered how they split between TX and RX and saw that they use an FET to split the signal. Well I added a J310 in the same manner to the TX side of the splitter and included a 6db pad after the coupling cap from the source and took 0dbm from there for DDS TX. Makes you wonder why I just didnít go directly to the output of FCC-2 and do the same? Iím sure I can but at this point it works and Iím not going to bother right now. I might also be able to use J1 for RF and 8 volts on the 10W linear as the plans call for :-).

*You can download any Elecraft manual at http://www.elecraft.com/http://www.qrp.pops.net/swl-ant-split.asp
*12/2/08 When the Pin Diode Switch kit came out I used one to switch DDS output for transmit and receive. Turned out to be a very simple solution.
=====================================================================================================
On 08/19/2008 10:58, ak2b posted:
I changed the Erector IF board to the HYCAS board http://www.ka7exm.net/. Intitially I just put it in and it worked fine. The input to the HYCAS is intended to be used with 50 ohms so I needed to make some calculations so that it would be compatible with the 200 ohm crystal filter. I used an on-line calculator at http://www.smeter.net/feeding/l_tuner.phphttp://www.ka7exm.net/ I plugged in values:
F= 5.067 (Freq)
A= 200 (Input R)
B= 0 (Input X)
R=2200 (Load R)
X=0 (Load X)
and got 19.87uh* for the series L (L1) and 45.5pf for the shunt capacitance (C1)(I didn't change C1)
I wound 62 turns on a T50-2 toroid using #28 wire. This worked fine with a very positive peak when tuning the input cap.
This is wrong of course because I looked at the first page of the QST article where the input resistor is 2.2K instead of 3.3K as in the actual schematic. In the actual schematic though, C1 is larger, so that was good. I never wound more turns on L1 and just left it. The HYCAS board works as advertised. Every signal sounds the same level. This is not necessarily good. After reading the notes at http://w7zoi.net/hycas-apps.htmlhttp://www.ka7exm.net/ I decided to short out R6 and change the AGC slope. I like this a lot better Ė so far. I will post some measurements later.

[img]http://tomnyc.no-ip.org/images/hycassm.jpg[/img]
=====================================================================================================
On 08/19/2008 12:04, YO6SSW posted:
[ak2b wrote:] "and got 19.87mh for the series L (L1)"


Just a quick question, Tom. Isn't that by any chance 19.87uH ?
=====================================================================================================
On 08/19/2008 12:40, ak2b posted:
Hi Adrian.

Yes, you are correct. I hope no one started to wind 2000 turns on a T50-2 :)
I changed it*.

Thanks.
Tom, ak2b
=====================================================================================================
On 08/19/2008 20:13, ak2b posted:
Here are up to date pictures.
The vertical box on the left houses the Universal Diode Ring Mixer and the post mixer amplifier (HF RF Amplifier).
I used SMA chassis mount connectors, that had pigtails of small coax attached, inside the double sided circuit board box. They were stripped from old CDPD modems. The cables with SMA male connectors were cut from defective GPS antennas. The FCC-1/2 Mark II connectors are BNC females. The +12V and FCC-1/2 key line are connected via feed through caps. The FCC-1/2 key line is via JP2 on the FCC-1 which tells the DDS which frequency to use in transmit mode. This connection is +5V through an internal pull-up resistor. I used an open collector transistor to bring it to 0V.
I didn't notice any differences after putting the above in boxes. Over-all it can't hurt, though, particulary the DDS.
The control panel on the front right is the volume control, the IF gain control from the HYCAS board, a keyer programming push button and below it, the paddle and earphone jack. I need to add an AGC on/off switch.


[img]http://tomnyc.no-ip.org/images/EfrontS.jpg[/img]

[img]http://tomnyc.no-ip.org/images/EBackS.jpg[/img]
=====================================================================================================
On 08/20/2008 09:25, ak2b posted:
This was recorded during the IOTA contest using the Norcal HYCAS Erector Pig Plus.
You will notice that I break a mini-pileup with my booming 4 watts :)
The band is a noisy 20 meters.

http://tomnyc.no-ip.org/iota_VX1RNS_P.mp3
=====================================================================================================
On 08/28/2008 09:04, ak2b posted:
The S meter circuit is from http://w7zoi.net/hycas-apps.html
The meter wouldn't move until a fairly strong signal, about S5 or S6, appeared. This eventually made sense after realizing I shorted R6 which gives the upper curve on W7ZOI/s web page. I removed the short just to see the difference and of course the response to lower signal levels was signifcant. I like seeing the meter move so I probably will leave R6 unshorted :).
The S meter is one that I puchased in the 70's on Reade Street, a remnant from 'Radio Row' just up from the World Trade Center. The meter is just lying there until I figure out where to permantly mount it. Later, I will put up a picture of the actual S meter hb circuit board.

[img]http://tomnyc.no-ip.org/images/smeter.jpg[/img]
=====================================================================================================
On 08/29/2008 09:56, ak2b posted:
Here is the homebrew S meter board from source given above

[img]http://tomnyc.no-ip.org/images/smeterboard.jpg[/img]
=====================================================================================================
On 09/04/2008 05:30, vk2nda posted:
The set is looking fantastic!

Today I started to mount my boards onto a blank PCB.

What was your motivation to replace the MultiPig+ AF AGC with the HYCAS IF Amp & AGC? How did you find AF AGC?

Did you have to modify the HYCAS IF Amp for use with a 5.06 MHz IF?

Regarding your switching of multiple BPF, can you use the PIN diode switches?

When it comes to adding further bands could you not utilise a single LPF for the highest band your set operates, without any serious problems at lower frequencies?

You may have already thought of this, but for saving space you could use threaded standoffs and stack the Twin BPF on top of each other if you didn't want to shift them over when you add 15 and 10.

Thanks for posting all the photos and comments. It's very helpful!

73
Nick
=====================================================================================================
On 09/04/2008 09:32, vk2nda posted:
One last thing...

I see you've placed the Universal Wideband RF amp after the mixer and before the XTAL filter. I was under the impression this would go before the mixer. Being a mere novice I'm not sure but, amplifying the incoming RF signal into the mixer would give it a better signal (using a wideband amp after the mixer would amplify the attenuated signals on the mixer output). The mixer would then attenuate out-of-IF-band signals. With this cleaner signal fed into the XTAL filter, and then being amplified by the IF Amp. If you were to place an amplifier between the mixer and XTAL filter I would have thought that another (narrowband) IF Amp would be the best bet, if still necessary.

Just to clarify what I said in my previous post about the PIN Diode Switch and BPF switching. It didn't at first click with me what the PIN Diode Switches were for. My educated guess from the schematic is that they are for switching between TX and RX when feeding into the common chain sections (LPF and or BPF). By why do you get two?

Anyway I was thinking that if you take your two BPF and place one PIN Diode Switch at either end you can tie the two pairs of 8volt control lines together and switch between the two BPFs by way of a toggle switch. Too much loss?

This might be stating the obvious or I maybe I'm way off with the function of the PIN Diode Switch.

What do you think?
=====================================================================================================
On 09/04/2008 10:30, ak2b posted:
Hi Nick,
Thanks for the comments.
[Nick wrote:] "What was your motivation to replace the MultiPig+ AF AGC with the HYCAS IF Amp & AGC? How did you find AF AGC?"


I used the HYCAS board mainly because I already had one and figured that this was a good place to try it. The AF AGC had a few problems like popping and poor recovery from a strong signal. It may have worked a little better if I had spent some time tweaking it. I think if I were going to use the High Gain IF board again I would just hang a 10K pot in series with with 12 volts and 4.7K resistor going to ground with the wiper going to pin 5 (This is a method used in another design I've seen using the MC1450).
[Nick wrote:] "Did you have to modify the HYCAS IF Amp for use with a 5.06 MHz IF?"


Other than the input inductor (explained above) I didn't change anything else. I think Wes Hayword (W7ZOI) mentions somewhere that the HYCAS would work down to about 4MHz. I haven't made gain measurements yet but did compare my voltages at different signal levels with the slopes shown at http://w7zoi.net/hycas-apps.html and did come up with something very close to what was shown.
[Nick wrote:] "Regarding your switching of multiple BPF, can you use the PIN diode switches?"


I don't know how to do this yet.
[Nick wrote:] "When it comes to adding further bands could you not utilise a single LPF for the highest band your set operates, without any serious problems at lower frequencies?"


I have seen LPF's used for 30/20, 17/15 and 12/10 meters but I don't think you would want to carry this too far and still maintain adequate filtering for your transmittter.
[Nick wrote:] "You may have already thought of this, but for saving space you could use threaded standoffs and stack the Twin BPF on top of each other if you didn't want to shift them over when you add 15 and 10."


Yes, I have thought of that and may eventually go that route. I used what I had on hand but have come to realize that you can never have enough hardware :). One of the great things about these kits is the many possibilities in construction design and layout. I am far from a final layout at this point and welcome any suggestions.
I am frankly surprised that even in the beginning stages of using these kits that I've had no problems with hum or extraneous noises even with the wires going all about as they are. Building on circuit board as ground plane probably helps.

Tom, ak2b
=====================================================================================================
On 09/08/2008 10:36, vk2nda posted:
Hi Tom,

I've been putting together a reply while I work on my own receiver and juggle some other things. I've come across a snag I wanted to run past you and the forum first.

I've now got mine running and receiving well. However there is a nasty hiss on the MC1249 IF Amp (which is reduced by using the MC1250). Injecting test signals at various points using the 8640B narrowed it down to the Amp.

Did you encounter this while using the erector IF Amp?

I also have a feeling that the IF Amp may at times be oscillating, although, being a novice, I'm not sure of this. There is a clean sine wave on the output when my flying coax test lead (usually attached to 8640B) is attached to the input of the IF Amp. I don't see anything on the bench that could be being picked up by the amp. It will also get a high amplitude sine if I give it some "finger coupling" of the MC1249/50 IC.

I love it when there is still something to figure out. It's like putting a great book down for a week when you're nearing the finish!

73
Nick
=====================================================================================================
On 09/08/2008 12:13, ak2b posted:
[Nick wrote:] "there is a nasty hiss on the MC1249 IF Amp"


Hi Nick,
The IF amp has a lot of gain. Pin 5 is the agc pin and applying a voltage there will give you plenty of control. As I mentioned above, you can use a 10K pot. Put a resistor (4.7K or there abouts) on the bottom leg of the pot to ground. Apply 12 volts to the top of the pot and connect the wiper to pin 5 of the MC1450. This will give you a cheap and dirty means to control the gain. I think Diz supplies a link to the spec sheet with the schematic. It is not a bad thing to get used to downloading them for reference. The MC1450 is also used in the MultiPig+ which is where I came up with my agc for it. It is also useful to take a look at an Elecraft K2 schematic and see how they used it. Leonard also has some notes on his web site. I don't know if you are using the IC audio amp but if you are, you might also download the spec sheet and look at ways to control its gain.
[Nick wrote:] "I love it when there is still something to figure out. It's like putting a great book down for a week when you're nearing the finish!"


Good point. These modular boards take you a step further than just following the directions as in a normal kit. It is easy enough to make modifications to suite your own needs. At some point I will spend more time with making measurements since I seem to have a much better understanding when I do. Leonard's videos make that perfectly clear.
I will get back to your other question when I return from vacation in a few days.

Tom, ak2b
=====================================================================================================
On 09/10/2008 10:54, ak2b posted:
[Nick wrote:] "I see you've placed the Universal Wideband RF amp after the mixer and before the XTAL filter. I was under the impression this would go before the mixer."


This is a very good question, Nick, and I don't (didn't) know the complete answer. However, since I have a black belt in Googling :) I put in "post mixer amplifier ham" and came up with a couple of good sites. http://www.qsl.net/wn5y/elrrfamp.htm and http://www.eham.net/forums/HomeBrew/5455http://www.qsl.net/wn5y/elrrfamp.htm. The first url will take you to a an amplifier that WN5Y calls one of the best ever designs for a post mixer amplifier. This is identical to Diz's Universal Wideband RF Amplifier :).
Also, for the real low-down on post mixer amplifiers, if you have Experimental Methods in RF Design, go to page 5.13 under the heading "Diode Ring Mixers and Related Circuits." If you don't have EMRFD I would suggest getting the book if you can. This pretty much tells the whole story.

A lot of things have come up since I started building my radio. Most of them I never questioned the rhyme or reason for. Prior to your question I would have told you that I used a post mixer amplifier because everyone else does.

On Diz's schematic he allows for terminating the amplifier with 50 ohms or 200 ohms to work with the impedance of the crystal filter. He also allows for a resistive (attenuator) pad termination. The resistive pad provides a non-reactive source for the crystal filter and instead of a 50 ohm pad I used a 200 ohm 6db attenuator with two 300 ohm resistors in series to ground a 150 ohm series resistor and two more 300 ohm resistors to ground. Why did I do this? I saw it in QRP Classics in "A Band-imaging Receiver for 10 and 18 MHz" which is very similar to my setup. Did it do any good? Probably, but I won't really know until I start making some measurements.

Tom, ak2b
=====================================================================================================
On 09/19/2008 13:41, steveratz posted:
Hi Tom,
Really nice job putting everything together. I'm especially in awe of your closeup view of the FCC 1/2 on the panel. (#6 picture). How did you get all 10 of those holes to line up; I only see the 3 button switches not quite perfectly centered.
I've built 3 of those and mounted 2 in enclosures and I had a terrible time getting the holes right. I didn't use 2 (bottom LCD) holes and it was still a struggle. There is no official template that I know of, and none of the dimensions are "standard". I had to first cut and file the LCD hole then try to line up all the other holes from that. Both my enclosures turned out but were far from perfect, and my LCD hole had gaps on all sides.
73,
Steve
=====================================================================================================
On 09/19/2008 15:33, ak2b posted:
Hi Steve,
Well, I have an FCC1/2 front panel grave yard here. What a pain in the butt! I did exactly what you did. I cut the hole for the LCD with a nibbler tool and mounted it by itself at first and drilled the four mounting holes. Then I mounted the LCD to the FCC-1 circuit board and carefully measured the distance to the switch holes. The FCC-2 part was also somewhat dumb luck with only one mistake. I measured as close as I could but still got it wrong. The screw to the right of the dial is a screw to nowhere. It didn't line up with the board so instead of doing it all over again I just said, "Thanks, but no thanks" and crazy glued it :). The one screw is enough.
I made an earlier FCC1/2 combo about a year ago in an aluminum enclosure that wasn't as tough to deal with as the PC board material. The one you see here is the new FCC-2 Mark II and the LCD is backlit which only allowed mounting with the two right hand screws to the FCC-1 board because of the size difference.

Tom, ak2b
=====================================================================================================
On 09/20/2008 10:42, steveratz posted:
Hi Tom,
Thanks for the comments on the FCC panel. I'm sort of glad I'm not the only one who had troubles mounting it, and I can surely sympathize with your own results. But your final results look good, and no one but us will ever know there's a dummy hole there, ha.
73,
Steve
=====================================================================================================
On 09/27/2008 12:14, ak2b posted:
Here is a recording of some contacts during the Texas QSO Party this morning with my NORCAL HYCAS Erector Pig Plus @4W on 20M. I am using the outboard NESCAF from the New England QRP club.

*http://tomnyc.no-ip.org/TexasQSOparty.mp3

*This is is a pretty big file (12,544KB) Sorry about that. I just loaded the software onto my new laptop and didn't bother to set the recording parameters before I realized I was doing stereo and a high bit rate :)
=====================================================================================================
On 09/30/2008 11:55, ak2b posted:
I was still getting some background hiss when the volume control was all the way down so I thought I might try and figure out why.
I made a gain measurement and found I was getting about *65db gain from input to output on the LM386 audio amplifier. When I removed the amplifier I looked at the components that control gain between pins 1 and 8. With the 10ufd cap connected directly across pins 1 and 8 you should get maximum gain *(200db). For some reason I had in my mind that the opposite was true and that you should get minimum gain *(20db) under those circumstances. I removed the cap and measured the gain again and got about 26db gain. The hiss was now gone while I still had plenty of volume. The receiver now sounds quite a bit quieter than before Ė a very nice improvement in over-all noise. I have no idea why with the 10ufd cap across pins 1 and 8 that I was only getting *65db gain. I have another LM386 amp on order and will test it and see if it does the same.
Again, looking at some of the Elecraft schematics, particularly the KX-1, it is interesting to see how they use the LM386.

There are a few other things I need to check out. I found out that the input impedance of an SA612 (Universal Gilbert Cell Audio Detector) is about 1.5K. The impedance looking back into the HYCAS board output is 50 ohms. I re-read Wesís notes on the HYCAS board where he mentioned that putting a 51 ohm resistor on the input to the SA612 might be ok. I'll give that a try.

Someone, (Allison, kb1gmx) on Yahoo EMRFD group) recently mentioned that she uses a 100pf cap from the output to the input of an LM386 to roll off some high frequencies. That's another thing to try.

Tom, ak2b

*this is incorrect and not possible. It should be about 46db. I apologize for my ignorance. I have mistaken gain as a ratio for gain in db.
=====================================================================================================
On 10/01/2008 09:54, ak2b posted:
I added the 51 ohm resistor to the input of the Gilbert Cell audio detector. I recorded the audio (band noise) before and after I installed the resistor and it sounds like this: (change is half way through)
http://tomnyc.no-ip.org/hycas_before_and_after_50ohm.mp3
I then downloaded a trial version of DSSF3 (looks like a real good program) from
http://www.ymec.com/products/dssf3e/index.htmhttp://tomnyc.no-ip.org/hycas_before_and_after_50ohm.mp3 and found the difference in gain to be about 6db. I still have plenty of audio gain. It was too late in the evening to hear anything on 20 meters. I'm not sure of any improvement and I don't really know how to evaluate this. I am sure of one thing, apparantly, I have gain to spare :). I'll give a listen tonight to see if I hear anything significant.
So far lowering the gain in the LM386 has made the most signicant improvement in the quality of what I hear (and don't hear).

I tried the 100pf cap from input to output on the LM386 but didn't notice any change.

Tom, ak2b
=====================================================================================================
On 10/03/2008 11:52, ak2b posted:
I got another LM386 audio amplifier and made some measurements. I measured with the 10ufd cap between pins 1 and 8 and with pins 1 and 8 open. With pins 1 and 8 open (minumum gain) I measured 26db. With the 10ufd cap between pins 1 and 8 (maximum gain ) I measured 46db. Both min and max gain measurements were identical to the spec sheet.
I kept wondering why the spec sheet was saying gains of 20db minimum to 200db maximum. As it turns out, they weren't saying this. The were saying gains of 20 and 200 (ratio of output voltage/input voltage). Expressed in db (20 * log V1/V2) this comes out to 26db and 46db respectively. How I came up with 68db in a previous post is beyond me.
The moral of this is - don't believe everything you read - particularly when it comes from me :). My apologies.

I hope to make more measurements like MDs, blocking dynamic range and two tone dynamic range tests in the near future. I will try and outline my test procedures so that if someone sees any glaring errors, they will tell me. This will be a first for me.

Tom, ak2b
=====================================================================================================
On 10/03/2008 18:38, kc0wox posted:
Tom:
All I have to say is you must be retired as you have way too much time. I still work for a living so I can't keep up with you. I have about 12 kits sitting and waiting for assembly. That may be a couple of years from now but it is coming down the pike.

You are doing a great job! I enjoy reading your posts.
Leonard
www.kc0wox.com
=====================================================================================================
On 10/04/2008 23:57, ak2b posted:
C'mon Leonard, the little LM386 Amplifier Kit takes 15 minutes to assemble. You can't tell me that you are not tempted to put together at least one of your 12 kits. I timed myself today and built the Gilbert Cell audio detector in 76 minutes. The diode ring mixer took a little longer. I figured I'd build up some boards and test them individually since on the first go around I was too impatient to get something working. Also, I can do different things with different boards and just swap them out.

I like to build and after building every kit available (or at least it seems) I got tired of just stuffing parts onto a board. The only time I would learn anything is when it didnít work. These little boards are a lot of fun and easy to modify and Iíve learned a great deal in the process of building my transceiver.

In any case, thanks for your nice comments and I hope it doesnít take years before you get back into building. Your web page on Double Balanced Mixers and screen shots from your spectrum analyzer are excellent and are better than any text book I've ever seen in explaining what happens with a DBM.

Although I would like to be, I am not retired and still work. I am not married and live in a city apartment so come Saturday morning there is no need to mow the lawn or mend the fences. I just make some coffee and head for the shop Ė which in my case is the dining room table - about a foot from where the coffee is made. :)

Tom, ak2b
=====================================================================================================
On 10/05/2008 15:10, kc0wox posted:
Tom:
My problem is after I build them, I want to test them and make a video and a web page. Thats what takes the time. I am lucky enough to have some test equipment, even if it is old, that is good. That along with the video hobby is what takes time. Also, I am very active on the bitx forum and have several things going on there.
Leonard
=====================================================================================================
On 10/14/2008 14:54, ak2b posted:
I spent the weekend trying to do some meaniful measurements with my Erector RX. This turned out to be more difficult than I anticipated. I used this document from the ARRL to run the tests:
http://www.arrl.org/members-only/prodrev/testproc.pdf
This is not the latest versions of the ARRL's test procedures but for my purposes it is good enough.

I am so unsure of the results that I'm not going to post them until I get a little bit more confident in my procedures. I have a K2 and plan to test both radios one after another. At least with the K2 I know around where I should be measuring.

Tom, ak2b
=====================================================================================================
On 10/15/2008 10:03, ak2b posted:
I measured the Minumum Discernable Signal (MDS) on the Erector RX and the K2 and came up with about -127dbm on both of the them. The specs on the K2 say -130dbm with the preamp off.
It was very hard to measure signal noise levels since they were jumping all over the place on my meter. I used the dbm scale on a program called Total Recorder to set the noise level to -6db and then adjust the signal generator (HP8640B) to read -3db on the same scale. I did the test three times on both radios and could duplicate the results as close as possible considering the jumpy meter. There is room for error here.
The K2 with no antenna connected sounds like it is dead :). It really comes alive with an antenna. I forgot how quiet the receiver is.

On to Blocking Dynamic Range.

Tom, ak2b
=====================================================================================================
On 10/16/2008 09:13, ak2b posted:
[img]http://tomnyc.no-ip.org/images/bdrtestsetup.jpg[/img]

The two step attenuators and the HP8640B I bought on eBay. I paid about $100 each for the attenuators and about $300 for the HP8640B. The Mini-Circuits ZFSC-2-6 http://www.minicircuits.com/pdfs/ZFSC-2-6.pdf was $50 direct from Mini-Circuits. After collecting all this over a period of time this is the first serious testing I have done with all of it together.
I quickly tried a BDR test on both units last night and came to the conclusion that quick tests aren't the way to go. The Erector RX looked better than the K2 by quite a lot. I know this can't be right.
The test procedures described by the ARRL left me a little confused. I will try again.

Tom, ak2b
=====================================================================================================
On 10/16/2008 18:44, kc0wox posted:
I've bid on 8640's several times but haven't been lucky enough to win yet. I use an IFR1200S from work to do MDS tests. I have an HP function generator and it works great as a signal source but it doesn't do any levels lower than -40 db out. I have an HP step attenuator but the function generator leaks out enough RF that any measurements below -40 db are useless. It is nice though as I can keyboard input a frequency in down to 1 uhz resolution.

I'm looking forward to the time in a few months that I can get back to the toolkits boards. I'm currently working an a manual for assembling a bitx20 version 3 pcb. You can see it at http://golddredgervideo.com/kc0wox/bitxver3new/newmanual.htm When I finish it, I have a few other things that I have been working on.
Leonard
=====================================================================================================
On 10/17/2008 10:43, ak2b posted:
Hi leonard,
I've gotten the best bargains on eBay just about Christmas time when people have their minds on other things. The HP8640B is a great instrument if you happen to get one in decent shape. I took a chance and bought mine without warranties and no proof of calibration. The XG2 is also quite handy since it puts out a pretty accurate low level signal at 1uv (-107dbm). One of the handiest pieces of test equipment I own is the FPM-1 power meter/frequency counter from m3electronix http://www.m3electronix.com/features1.html I also bought the RF Calibrator from them. It claims to measure RF down to -72dbm. I put it up there in usefulness with my AADE L/C meter - you can live without it, but I'd rather not.
Talk about having enough time, I looked at your manual and other things you've done with the Bitx20. That's a lot of work, Leonard :).

Tom, ak2b
=====================================================================================================
On 10/28/2008 11:38, ak2b posted:
My test results are just too flakey at this point so Iíve decided to hold off writing anything on the subject until I feel more confident. I was trying to do a 20KHz Blocking Dynamic Range test when I found the that the Universal Dual Band Pass Filter could be peaked significantly only 20KHz away which was very likely going to throw of any meaningful measurement. I have the wide band (single band) version which I will put in later. There were other problems that cropped up like not getting the same results every time I ran the tests.
I have a few of the pin diode switches made up that I want try out and will report on them in a bit.
In the meantime, I use this transceiver almost daily and can tell you that it works quite well. Aside from the low power and being in the armpit of the sunspot cycle, I've still managed to have some really solid QSO's stateside as well as having worked about 20 countries.
I also need to box this radio up a little tighter as it has grown unwieldy in size :).
=====================================================================================================
On 11/06/2008 10:42, ak2b posted:
[img]http://tomnyc.no-ip.org/images/ErectorRXFilters.jpg[/img]

One row of the BPF's, LPF's and pin diode switch boards are mounted on the back of the transceiver. The pin diode switch between the low pass and band pass filters, I realized after I mounted it, is not needed since it is duplicated on the transmitter board. I rewired the transmitter board according to the schematic to accommodate using the LPF for both transmit and receive. Actually, I could probably also use a pin diode switch on the output of the DDS VFO to switch between the TX and RX frequency and do away with the splitter and attenuator entirely. The switch on the left below the meter position will handle the TX/RX voltages for three bands so I'm adding 15 meters to my original 20M/17M transceiver. I should be finished by this weekend and will report further.
Sometimes I feel like the dumbest person on earth. Forever I thought that the labels XMIT+8 and RCVE+8 at J1 on the linear amp meant the signal lines plus 8 volts. This threw me off for the longest time until I saw the pin diode switches with the same labels. Finally it dawned on me that this lines were simply 8V TX and 8V RX. Oh well, it's not the first time I've been so stupid, when I was first licensed in the early 60's, for years I thought SKN was Silent Key Night :).

Tom, ak2b
=====================================================================================================
On 11/09/2008 13:29, ak2b posted:
[img]http://tomnyc.no-ip.org/images/ddspinswitch.jpg[/img]

After wiring everything up for 20 meters and listening to the receiver I now had birdies all over the place. I figured adding a pin diode switch to the FCC-2 might solve the problem since one output would be muted during transmit or receive. Well, it didn't work out that way. After checking everything I could think of I found that while in receive I still had considerable output on the transmit side of the pin diode switch and therefore the TX output of the FCC-2 going to the BPF was very strong causing hetrodynes . The problem eventually turned out to be that the 8 volt transmit switch still had about .4 volts on it when it should be 0V during receive. I have four inputs to the 8V transmit line and when I disconnected the one going to the Linear Amplifier (J1 pin 1) the line would go to zero volts and the birdies disappeared. This .4 volts was enough to cause a problem with the pin diode switches or at least they did on my rig.
At this point, I've got to figure out why I have the .4 volts. If anyone else has the Linear Amplifier and could check pin 1 of J1 it would be a big help. Otherwise I could just add another transistor for supplying +8V to the linear.
Aside from this problem the Pin Diode Switchs are pretty cool and fairly easy to implement.

Tom, ak2b
=====================================================================================================
On 11/10/2008 17:15, ak2b posted:
After poking around Q1 on the Linear Amplifier the TX 8 volt line (J1 pin 1) went to 0 volts while in receive and everything sounds fine. Why the problem went away, *I don't have a clue. It doesn't appear to be intermittant - just a solid 0 volts while in receive. The downside to all this is the power dropped down to 1.5W :).
Oh well, time for a little trouble shooting.

Tom, ak2b

*I have a feeling, now that I think about it, that the TX voltage problem might have come from poor grounding on the Linear Amplifier and moving the board around may have temporarily solved the issue.
*11/20/08 Actually, the voltage comes from Q1 through R2.
=====================================================================================================
On 11/12/2008 22:40, W4GNS posted:
OK, I could not stand the pressure of seeing AK2B's post/pics any longer, I finally started melting solder today, and got the IF Amp board done, I'm away from home on the left coast and had lots of distractions from the folks I work with ,so little got done, maybe tomorrow I'll get more boards done. Where is a good source to get the copper board to mount the kitlet boards to? Another question, Tom , what software are you using to record your sound files? I have lots of questions , so I figger I can light this board up with questions !!
73 Gary W4GNS
=====================================================================================================
On 11/13/2008 09:15, ak2b posted:
Hi Gary,

Glad to see you are getting started. Maybe now I won't be so lonely here :)
I bought my double sided circuit board material about 4 years ago on e-Bay but I canít remember where. A quick search shows there are still a lot of suppliers though the price looks a little higher than I remember.
Originally, I recorded with Sound Recorder supplied with Windows XP but found it a little limiting. I ended up buying Total Recorder for $18 which was a lot more versatile. http://www.highcriteria.com/ There are probably other programs out there that do an equal or better job and might even be free Ė I didnít research it that much.
Have fun and I look forward to hearing/seeing your results.

Tom, ak2b
=====================================================================================================
On 11/15/2008 15:33, W4GNS posted:
Question 1 : Anyone know what we shoulld be expecting feature wise with the up coming Keyer for the RF Tool Kits boards? Diz any comments?

Question 2 : Should I/we be starting new topics on this forum, or just riding along on AK2B's thread?

Comment: Just put in a decent order to Papa Diz so should have lots of boards in a few days ;-), also ordered a extra mixer board so I may start a new project, as Diz only gives the very bare minimum of info, so us folks that are RF ignorant have to actually read the handbooks and google alot, which in turn inspires new projects and ideas ....hummmmmm, wonder if that is intentional?
=====================================================================================================
On 11/16/2008 18:36, kc0wox posted:
Gary:
Have you seen my videos page for the Kits and Parts boards? It's at http://golddredgervideo.com/kitsandparts/index.htm and if you haven't seen the mixer one, be sure and take a look.

I haven't had any time to expand it for a while.
Leonard
=====================================================================================================
On 11/16/2008 19:06, ak2b posted:
[w4gns wrote:] "Question 2 : Should I/we be starting new topics on this forum, or just riding along on AK2B's thread?"


Hi Gary,
Feel free to start a new topic.
Tom, ak2b
=====================================================================================================
On 11/16/2008 20:43, W4GNS posted:
Hi Leonard
Yes, I am aware of your videos but need to see them again, later maybe, as I use a wireless connection for internet and my current location is very slow, I'm in southern Washington hauling WindMill blades and expect to be here through the winter, so no prime and fast connection for awhile, unless they upgrade the towers while I'm here ;-) I'm trying to download the mixer video now, but it does not look good, my connection is really shakey here, If I were back out east 180megs would only be a few short minutes
And so noted on new topics Tom
Thanks guys

PS Leonard , I do have my copy of EMRFD and the 2007 ARRL Handbook with me, so all is not lost ;-)




[kc0wox wrote:] "Gary:
Have you seen my videos page for the Kits and Parts boards? It's at http://golddredgervideo.com/kitsandparts/index.htm and if you haven't seen the mixer one, be sure and take a look.

I haven't had any time to expand it for a while.
Leonard
"


=====================================================================================================
On 11/26/2008 14:23, ak2b posted:
This is pretty much where I am now as far as figuring out how to switch bands. I found out that the Pin Diode Switches can only handle 10mw :) I put a diode in series with R2 on the Linear Amplifier to keep voltage from appearing on the +8V TX line while in receive. This cured the problems with hetrodyning. The Linear Amplifier is back to being fed the way it is in Diz's schematic.
The relays I used here are what I had on hand but eventually I may add 15 meters and this may change the type of relays used.
Tom, ak2b

[img]http://tomnyc.no-ip.org/images/erectorblockdiagram.jpg[/img]
=====================================================================================================
On 11/27/2008 11:02, kc0wox posted:
Take a look at the specs for these relays. http://pdf1.alldatasheet.com/datasheet-pdf/view/230409/MACOM/V23079-A1011-B301.html If you are interested, I will send you what you need. I have about 100 of them I purchased for another project. I think I paid about 15 cents apiece. I have the dpdt non-latching with a 12 volt coil circuit board mount. V23079-A1011-B301 is the part number of what I have. I can probably get a few thousand more if you needed them. It says they will switch 5 amps or 60 watts. They are a little over 1/4" wide and a little over 1/2" long.
Leonard
=====================================================================================================
On 11/27/2008 20:21, ak2b posted:
Hi Leonard,
That is a very generous offer. I e-mailed you off list with my request.
Thanks,
Tom, ak2b
=====================================================================================================
On 11/29/2008 10:45, ak2b posted:
*http://tomnyc.no-ip.org/cqwwdxSunday.mp3


I changed the mp3 to a recording made on Sunday with a lower bit rate so the file is smaller. The board where the keyer chip was mounted was loose and hanging as I was doing some other work on the radio. I remounted it and it sounds a lot better. I used a 15W outboard RF amplifier while this was recording. My 4 watts or so wasn't getting any results as I started later in the morning after the band had changed a bit. The QSK is not quite as good but the results were better.
My original message is posted below as quoted by Gary

Tom, ak2b

*this is a 2MB file
=====================================================================================================
On 11/29/2008 11:41, W4GNS posted:
Sounding GREAT Tom, Get-er-Done!!
I do have have a question. I spent 4 years running around NYC and Long Island as a mobile, I found the city almost impossible to hear much for the noise, of course Long Island was not too bad. What are you using as an antenna and how are you defeating the extreme noise?
73 Gary W4GNS




[ak2b wrote:] "*http://tomnyc.no-ip.org/cqwwdx08.mp3

Sorry about the lousy sounding sidetone.

Here is little Saturday morning CQWWDX on 20 meters at 1300Z. I started off ok at 1300Z and worked S57DX(Slovenia), M6T(England) and ES5TV(Estonia). I took a coffe break and came back at about 1400Z and had a hard time working anyone until OG2M(Finland) at the end. The band changes that quickly in the AM here.
Contests are great for the QRP ego. So many of the EU's have contest clubs with antenna farms as large as Rhode Island. Fortunately, they can hear my 5 watts quite easily. Sometimes later into a contest, the weaker signals are not to be dismissed since a lot of them are running low power with a good set of ears :)
Sometimes I use MixW's cw decode mode on the contest stations sending cw at mach III. If the qrm isn't all that bad, MixW can copy them pretty well.

Tom, ak2b

*this is a 4MB file
"


=====================================================================================================
On 11/29/2008 13:46, ak2b posted:
Hi Gary,
In Manhattan the utility poles are underground which helps a lot. My antenna is a Force 12 GT-5 vertical dipole on top of the apartment building where I live. It is up about 110 feet from the street which is good but I had to run 200 feet of coax to get to my rig. 20 meters, which is my favorite band, is usually pretty quiet although I get my share of "what the hell was that?" noises that come and go at random. 40 meters is very noisy around here but then 40 meters can be pretty noisy anwhere.
I was operating mobile up until 6 months ago when I got another car and haven't reinstalled the rig yet. Other than the usual noises from traffic lights, city buses, etc. by the time I got on the Belt Parkway, on my way to work, I could work the world with very little effort with an IC-706, AH-4 and a Radio Shack CB whip. Driving near the ocean never hurts :).

Tom, ak2b
=====================================================================================================
On 12/01/2008 18:57, ak2b posted:
I just finished this 40 meter receiver with universal VFO
It works pretty well but I ran out of mounting hardware so it's just pinned to a cardboard box :). Hardware should be in this week.

[img]http://tomnyc.no-ip.org/images/40meterRX.jpg[/img]

Tom, ak2b
=====================================================================================================
On 12/01/2008 19:14, W8DIZ posted:
Hi Tom,

I built the same style rig but had the RF amp in front of an SA612 Mixer
All the rest was the same.
=====================================================================================================
On 12/01/2008 20:14, ak2b posted:
[W8DIZ wrote:] "I built the same style rig but had the RF amp in front of an SA612 Mixer
All the rest was the same.
"


Hi Diz,
Did you put an rf amp after the sa612 mixer or did you go straight into the crystal filter?
=====================================================================================================
On 12/01/2008 20:52, W8DIZ posted:
[ak2b wrote:] "Did you put an rf amp after the sa612 mixer or did you go straight into the crystal filter?"


Yup...no amp after the mixer.
The SA612 has gain...so no need to place an amp after the SA612 mixer to the Xtal filter.

-Diz
=====================================================================================================
On 12/01/2008 22:29, W4GNS posted:
The toroid on your VFO looks fine, at some point in my life I gotta wind mine...... too bad DIZ did not offer to wind that for 2 bucks, like he did for soldering the SMT diode on the diode ring mixer board =D

UPDATE: After posting the above comment, I checked my VFO bag, its still in the same condition that DIZ shipped it =( So I figured it was time for me to do it , since it does not seem willing to wind itself. To be honest I enjoyed winding it so much , I wound it a second time !! don't ask !

foot note: its a VERY good idea to take extreme caution when cutting the tape after being applied to the toroid to NOT cut the pig tail flush with the 'roid =) (yea, I cussed)


[ak2b wrote:] "I just finished this 40 meter receiver with universal VFO
It works pretty well but I ran out of mounting hardware so it's just pinned to a cardboard box :). Hardware should be in this week.



Tom, ak2b
"


=====================================================================================================
On 12/02/2008 10:05, ak2b posted:
Overall, I've found that gain is definitely not an issue with the two receivers Iíve built. In fact, just the opposite, there is way too much gain. Which is why I used the 10K pot to apply voltage to pin 2 of J4 on the IF amp and lower the gain in the audio amp by adjusting R3. I also found an immediate need for audio filtering Ė which makes a big difference.
Just for fun, I swapped the RF amp from the output of the diode ring mixer to the input but really couldnít hear much difference. Then again, it was late and the band was dead. Itís nice that itís so easy to do :).

Tom, ak2b
=====================================================================================================
On 12/02/2008 10:47, kc0wox posted:
The reason to have the rf amplifier first is to establish a low noise figure. That might be a big deal at 6 meters but on the lower frequencies, the external noise will be higher than the internal noise figure anyway.

The rig looks great!
Leonard
=====================================================================================================
On 12/06/2008 17:14, ak2b posted:
I found a variable crystal filter described by YU1LM here:
http://yu1lm.qrpradio.com/XTAL-VAR%20FILTER-YU1LM.pdf
It looked interesting because it was simple and has a 50 ohm input and output termination.
Using one of Diz's Universal Generic PCB's I built up the circuit (the smd resistors are on the bottom):

[img]http://tomnyc.no-ip.org/images/varcrystalfilter.jpg[/img]

It worked ok. I didn't really have the right varactor diodes to get a narrow enough CW bandwidth so I put them in parallel which was better but still not quite what I want to see.
Here are some Spectrograms that give you an idea of performance:

[img]http://tomnyc.no-ip.org/images/variablefilternarrow.gif[/img]
[img]http://tomnyc.no-ip.org/images/variablefilterwide.gif[/img]

And lastly a Spectrogram the audio detector adjusted for SSB.
[img]http://tomnyc.no-ip.org/images/variablefilterssb.gif[/img]
Which sounds like this (you can hear the pot being varied between wide and narrow in the beginning and near the end if you listen closely). The recording is K6AER.
http://tomnyc.no-ip.org/k6aerssb.mp3http://yu1lm.qrpradio.com/XTAL-VAR%20FILTER-YU1LM.pdf

I think I need to get some other varactor diodes. The ones Elecraft uses look pretty good with a nice wide C min/Cmax ratio. They are 1SV149's. I couldn't find them anywhere. As a matter of fact, Mouser doesn't seem to stock any varactor's.

Tom, ak2b

P.S. Those Generic PCB's are really very nice. They take SMD's very nicely :)
=====================================================================================================
On 12/06/2008 17:55, W4GNS posted:
Tom
A quick google search popped up 1 result here http://www.bdent.com/search/part.jsp?partnum=1SV149B they appear to be available in small quanities

I just noticed there is a $15.00 min order
=====================================================================================================
On 12/08/2008 14:07, ak2b posted:
Gary, Elecraft wrote me back and said they (1SV149) would be $0.80/ea. Not bad. That's a lot better than $3.88/ea.

Tom, ak2b
=====================================================================================================
On 12/08/2008 14:14, W4GNS posted:
At that price difference, I think you better get extras! Thanks for the update, Tom

After even more research, I see you're getting a steal Tom,found these http://www.mouser.com/Search/Refine.aspx?Keyword=MVAM109
should serve the same purpose but different, not sure why I'm researching, cuz I have no intentions of doing the variable BW filter =)

[ak2b wrote:] "Gary, Elecraft wrote me back and said they (1SV149) would be $0.80/ea. Not bad. That's a lot better than $3.88/ea.

Tom, ak2b
"


=====================================================================================================
On 12/13/2008 18:48, ak2b posted:
I made a grainy (not on purpose) video clip of my 40 meter receiver with VFO. I did it with my regular digital camera. The sound is picked up from cheap computer speakers and doesn't sound nearly as good as through ear-buds. In the movie I mention that I can't remember where the display came from. It is from KD1JV and sold by QRPkits.com. I would caution anyone thinking of building it since it uses little tiny 802 size smd's. Without some experience, you might find this kind of difficult. I put solder paste on all the pads, mounted the parts, put it on a heating tray used a heating gun when the paste turned dull gray. I only had one short between IC pins and two pads where I forgot to put solder. It came out pretty well. It is coupled to the VFO output through a 4.7pf cap.

tomnyc.no-ip.org/ErectorRXmovie.wmv

...And a short recording that I made earlier from the same receiver, when the band was a little better, that sounds more like the radio.

tomnyc.no-ip.org/All_Homebrew_Here.mp3tomnyc.no-ip.org/ErectorRXmovie.wmv

Tom, ak2b
=====================================================================================================
On 12/14/2008 02:52, W4GNS posted:
Tom
What bandwidth's did you end up with, with your own crystal filter? Or is that the Nescafe that is helping to? I like tight filters and yours appears to be tight.
Slowly but surely I'm making some progress, I will use the multipig + PLL with my rig (I hope). These 14 hour work days are really making my hobbies tough to make time for ;-(
Fine show Tom........


[ak2b wrote:] "I made a grainy (not on purpose) video clip of my 40 meter receiver with VFO. I did it with my regular digital camera. The sound is picked up from cheap computer speakers and doesn't sound nearly as good as through ear-buds. In the movie I mention that I can't remember where the display came from. It is from KD1JV and sold by QRPkits.com. I would caution anyone thinking of building it since it uses little tiny 802 size smd's. Without some experience, you might find this kind of difficult. I put solder paste on all the pads, mounted the parts, put it on a heating tray used a heating gun when the paste turned dull gray. I only had one short between IC pins and two pads where I forgot to put solder. It came out pretty well. It is coupled to the VFO output through a 4.7pf cap.

tomnyc.no-ip.org/ErectorRXmovie.wmv

...And a short recording that I made earlier from the same receiver, when the band was a little better, that sounds more like the radio.

tomnyc.no-ip.org/All_Homebrew_Here.mp3tomnyc.no-ip.org/ErectorRXmovie.wmv

Tom, ak2b
"


=====================================================================================================
On 12/14/2008 10:17, kc0wox posted:
I have 2 videos on the digital dial. One on assembly and one on troubleshooting it. You can see them at:
http://golddredgervideo.com/kc0wox/digitaldialassembly.wmv

and

http://golddredgervideo.com/kc0wox/digitaldialtroubleshooting.wmv

They are large files, 124 meg and 212 meg so may take some time to download.
Leonard
kc0wox.com
=====================================================================================================
On 12/14/2008 16:45, ak2b posted:
[w4gns wrote:] "What bandwidth's did you end up with, with your own crystal filter? Or is that the Nescafe that is helping to?"


Gary, the crystal filter you were listening to is the variable bandwidth filter - the curve is shown in a previous post above. The Nescaf helps a lot and I wouldn't use the receiver without it at this point. You need some sort of audio filter in my opinion. There is probably more than one solution to this like using something before or after the audio amplifier instead of using an outboard filter like I do. I like the Nescaf which is probably why I haven't spent too much time on another approach.
Also, having the IF pot can make things sound pretty quiet. I can see why some hams prefer to ride the IF gain(or in most cases, the RF gain) instead of using their AGC. The only thing you have to keep an eye on (or ear on) is coming across a sudden strong ear-splitting signal :)

Tom, ak2b
=====================================================================================================
On 12/15/2008 10:50, ak2b posted:
I've added a Universal Dual BandBass Filter (20 and 17 meters) and another FCC-1/2 to get multiband by moving a few jumpers.
The pots are all 10K and going from left to right are the variable crystal filter pot, IF gain pot and the volume control.
The two left pots have 4.7K resistors on the ground side and the input side is connected to the 8V line with the center as the control lead. The filter pot is not connected as it previously shorted to the circuit board when it wasn't mounted and now the variable crystal filter doesn't want to work anymore :(. I replaced the pot since it acted like a fuse. The crystal filter in there now is a narrow, about 350 Hz filter.
I mounted a small piece of PC board material on a nylon standoff and soldered the main +12V lead to it. I also mounted a strip of 5 pins (the same as the 3 pin female connectors at the end of each small board) on the same board so that I would have several sources of +12 volts. I did the same a strip of ground pins soldered directly to the main PC board backplane. You can never have have enough voltage sources.
I found a reference Diz gave in the FAQ notes on the MultigPlus and ordered a bulk supply of connectors from Jameco. http://kitsandparts.com/faq.php

Video:
tomnyc.no-ip.org/ErectorRXdds.wmvhttp://kitsandparts.com/faq.php

So now I have a decent platform for adding/removing/changing boards and general experimenting.
Now if I only knew what I was doing :).

Tom, ak2b
=====================================================================================================
On 12/15/2008 12:50, W4GNS posted:
We are suppose to know what were doing?!?!?!?!?! First I have heard of that =)
News Flash: I have upgraded my mobile lab ! (Youre gonna love this one Diz) see second picture http://www.w4gns.com/trk.html

[ak2b wrote:] "Now if I only knew what I was doing :).

Tom, ak2b
"


=====================================================================================================
On 12/15/2008 15:45, kc0wox posted:
Nice video. The setup looks good.

I don't know about that funny souning, intermittant, tone that was on the speaker though. I was waiting to hear someone speak.
Leonard
( a newly licensed no-coder )
=====================================================================================================
On 12/24/2008 09:58, jaswarb posted:
Hello Tom,

I am Jim Benson NS5U. I am collecting parts to build a 30/20 meter version of a "Dizzy Transceiver" and have a few questions. I have been following your developing rig with great interest. I have aquired a FCC-1/2 for the VFO and now I am looking for guidance to choose the RF-ToolKits to accompany it.

Specifically:

Choice of IF frequency would seem to be narrowed to the 4mhz crystals available here as the second harmonice of the 5mhz crystals would fall in the middle of the 30 meter band but the BFO kit mentions choosing the 5mhz crystal for use with the other kits. Can I successfully use the 4mhz crystals?

Would I need just the Gilbert Cell Audio Detector or do I need the BFO kit as well?

Can I change the passband characteristics of the Crystal Filter Kit with different capacitor values. I am curious about the effect of changing the shunt capacitor values and the possibility of using varicap diodes for an adjustable bandwidth. What would you suggest?

Considering the IF amp seems to have excess gain is the wideband preamp either pre/post mixer necessary?

Will the receive path benefit from routing through a low pass filter?

I am learning a great deal from your posts and those of KC0WOX(his videos are tremendous vicarious thrills).

I would encourage anyone lurking to jump in here for the benefit of all.(particularly me)

tnx de
Jim Benson
NS5U/1
=====================================================================================================
On 12/24/2008 13:56, ak2b posted:
Hi Jim,
Welcome to the group.

[jaswarb wrote:] "Would I need just the Gilbert Cell Audio Detector or do I need the BFO kit as well?"


I think the Gilbert Cell audio Detector with the 4MHz crystal would do just fine. You may or may not have to tweak the values of C4 or C5 - Diz might jump in and answer that. One thing you have going for you is that 4.9Mhz is what Elecraft uses for an IF in all their rigs except the K3. I have all their manuals downloaded for reference. There is a lot of good information there. They use the SA602 as a detector which I don't think is all that different from the SA612.

[jaswarb wrote:] "Can I change the passband characteristics of the Crystal Filter Kit with different capacitor values? I am curious about the effect of changing the shunt capacitor values and the possibility of using varicap diodes for an adjustable bandwidth. What would you suggest?"


Yes, you can choose your capacitors for the passband of your choice. Looking around the forum you will see that I've tried a variety of options - even a variable bandwidth filter. I used 120pf and got a passband of approximately 800 Hz. Diz suggests 470pf for 500Hz. I just got 10 SV149' varactor diodes for a variable crystal filter that I have been experimenting with (they were $0.80 each from Elecraft). I haven't had the chance to try them yet.

[jaswarb wrote:] "Considering the IF amp seems to have excess gain is the wideband preamp either pre/post mixer necessary?"


Diz says he used the amp before the mixer but then he was using the Gilbert Cell mixer which has gain. If you are using the diode ring mixer, which has some loss, I would use it after. I put a 200 ohm pad on the amplifier output to give the crystal filter input a nice non-reactive source to look at. You can wire the amplifier for 50 or 200 ohm output impedance. ~200 ohms is the impedance of the crystal filter. The IF amp does have a lot of gain. On one of my boards I use a variable resistor on pin 5 to control it. I have no agc, but the pot works fine as an IF gain control.

[jaswarb wrote:] "Will the receive path benefit from routing through a low pass filter?"


The benefit of the low pass filter on receive isn't as obvious as it is for transmit. In other words, if you left it out while listening to your receiver you might not hear any difference. On the other hand, it will keep things like VHF interference and other extraneous garbage out of your front end. There are a lot of different front end designs floating around these days for you to pick from. I just tend to lean on the conservative side for the time being and trust what others have done, mainly because I don't know any better :). The great thing about using these little boards is that you are not stuck to any one way of doing things. I fully plan to try other designs just as soon as I've understood as much as I can from the present one. I built a W7ZOI/K5IRK 'Progressive Receiver' in the 80's and I guess in my mind this is the correct way to do things. In any case it is interesting to note that the post mixer amplifier that Diz sells is the exact same one as in the Progressive RX - a good, solid, time tested design.

Have fun and please keep us informed of your progress.

Tom, ak2b
=====================================================================================================
On 01/21/2009 20:49, ak2b posted:
I bought an N2PK VNA and made this *scan of the 15 meter Band Pass Filter with it. I just got this VNA and this is my first scan. I have to admit that I am way over my head with this piece of gear at this point - and to tell the truth, I'm happy to have made this much progress :). It is cool that the scan runs fast enough that you can tune in real time and see your progress. Hopefully, in due time, I will be able to test crystal parameters, do impedance measurements and other good things.

Tom, ak2b
[img]http://tomnyc.no-ip.org/images/15MBPF.jpg[/img]
*scan revised on 1/24/09 after I reset the proper clock frequency in the VNA Software(steep learning curve :))
=====================================================================================================
On 01/23/2009 10:53, W4GNS posted:
Tom
I would enjoy continued updates on the analyzer. I came very close to ordering a kit this past fall , but at present just don't have the time. Maybe we could talk Papa Diz into a new thread related to stuff not directlt related to the "Dizzy Transceiver" ;-)
=====================================================================================================
On 01/23/2009 12:59, ak2b posted:
Since I got the analyzer mainly for working with the RF Toolkits (at least for the time being) I will probably post the results I get right here as I go along.
I originally thought I would build the analyzer but when I added up the things I would need, the price kept on growing and growing. Originally hams were saying you could build it for a few hundred dollars but as time went by and the analyzer project grew with things like dual ADC's and USB various clock options, etc., the price climbed up to about $600 for a complete package, if I remember correctly. Anyway, there came a point where confusion over the various versions set in and whether I wanted something to build or something I wanted to use. Building it would have taken up a lot of time and the fear that in the long run it might not work as planned, so, I bought one :D. http://www.m0wwa.co.uk/page/vna.html It wasn't cheap, slightly over $1K (the British pound has dropped some against the US dollar) but it works and is built beautifully.
Gary, I don't think Diz minds if you or anyone else starts an unrelated topic as long it avoids politics and religion :).
=====================================================================================================
On 01/23/2009 15:22, W8DIZ posted:
[ak2b wrote:] "Gary, I don't think Diz minds if you or anyone else starts an unrelated topic as long it avoids politics and religion :)."


Go for it. More stuff to read :)
-Diz
=====================================================================================================
On 03/23/2009 09:39, ak2b posted:
This is a complete transceiver made with the RF Toolkits for 40 meters. The only thing I didn't do was use the receive part of the BFO to the Gilbert Cell Audio Detector since this board already has a crystal. The complete kit works quite well.

Tom, ak2b
[img]http://tomnyc.no-ip.org/images/FullToolKitXCVR.jpg[/img]
=====================================================================================================
On 03/23/2009 10:25, ki4mmm posted:
Nice!! I have an(RFToolkit) audio detector w/ crystal on board, but I can't remember, is it already "up" 600Hz (or can it be adjusted such), or did you handle your TX-RX freq differences differently?

Greg
ki4mmm
=====================================================================================================
On 03/23/2009 10:56, ak2b posted:
[ki4mmm wrote:] "I have an(RFToolkit) audio detector w/ crystal on board, but I can't remember, is it already "up" 600Hz (or can it be adjusted such), or did you handle your TX-RX freq differences differently?"


You set it to 600Hz using C5. What I do is use MixW and put a marker at 600Hz and center the passband around it. You can also use Spectrogram http://www.n0ss.net/index_k2.html which is better (and free). The notes are for the K2 but apply as well to any receiver. You can use a noise generator which is best but you can also get away with band noise.

Tom, ak2b
=====================================================================================================
On 03/23/2009 14:31, ki4mmm posted:
I've used Spectrogram on my K2 and couple of SDR/DRM projects - great idea, thanks!

Greg
ki4mmm
=====================================================================================================
On 03/25/2009 08:11, wa8qfe posted:
Has anyone tried the new RF transistors that DIZ sells, on either of his PA boards ?
Lee, WA8QFE
=====================================================================================================
On 03/25/2009 09:05, ak2b posted:
If you are refering to the 2SC2166; not yet - I just got some from eBay.
(Not realizing that Diz was selling them on his website, I bought them on eBay. Well, as it turned out, after I bought them, I discovered the the eBay seller was Diz :) )

I haven't tried them yet. When I do I'll let you know. I have tried using the 2SC1969 but it didn't work.

Tom, ak2b
=====================================================================================================
On 03/25/2009 15:24, wa8qfe posted:
Tom,
Thanks and one of us will try them.
The K1 used the 2SC2166 as the driver for the 2SC1969 final.
Now they use the 2SC5739 as the driver, and it appears there is no modifications needed.
The K1 folks said the change was only a supply issue....guess DIZ controls the market now for the 2166.
I have at least 1 of every kit DIZ has and more of most of them..I am a contract avionics tech for airlines and just finished 7 months on United Airlines planes in NC and now heading to Indy. I keep building and all ends up in storage at the home QTH in MO.
Lee,WA8QFE
=====================================================================================================
On 03/31/2009 10:40, ak2b posted:
Lee,
I tried the 2SC2166's in the 5W CW Amp but didn't notice much of a difference. I put back the originals and promptly blew them out :) For some reason the amp works fine into a dummy load but don't like my antenna much. I checked everything I possibly could with my VNA (antenna and LowPass Filter)and everthing looks ok. It's very strange. I haven't figured out what the problem is. For some reason, not all the time, I get a very high, intermittant, SWR into the antenna. When I put back the dummy load, everything is good again. Other radios into the same antenna don't exhibit this problem. I'm stumped for the moment. I rechecked all the soldering. This is the first time I've put the amp on the air and while previously testing, I had only used a dummy load.
I have torn down the board pictured above and am now using an FCC-1/2 in place of the VFO, BFO, and TX mixer. I'm getting about 6 watts out on 20 meters but can get a lot more on 40 (about 10W) when all is good.
Tom, ak2b
=====================================================================================================
On 04/01/2009 13:13, ak2b posted:
I think the problem was overdriving the input. I forget to reset the FCC-2 output after using it for the QRSS transmitter :). With the output set at +1dbm, everything looks good now.

I use one half of a Pin Diode Switch board with the center pin of J2 connected to the high side of T4 on the QRP Amp. J3 is connected to the BPF and I use the RCVE+8 line at J4 to switch between transmit and receive. So far, it seems to work ok.

*disclaimer
If at any point when reading my posts it appears that I know what I'm doing I hearby give you the right to slap me. Any resemblance to actual knowledge is purely coincidental.
=====================================================================================================
On 04/05/2009 04:51, wa8qfe posted:
I'll try the 2166's with my amp soon. I.m looking for a little more power out on 17 meters. I didn't lay the finals flat on the board
with the 5 watt amp. I got a nice pair of heat sinks from radioshack,and I moved the 47pf capacitor to the bottom of the board.
I'll make a trip to the home qth soon and retrieve all my boards.
I'm in an extended stay hotel, now at Indianapolis airport for the next few months, and need to make the room smell like solder.
Lee, WA8QFE
=====================================================================================================
On 04/06/2009 13:13, AA4W posted:
Tom,

Thanks for all the great posts and good info! I just ordered a VFO from Diz and will be nipping at your heels before long.

It looks like great fun! And a reason to melt some solder.

Rick AA4W
=====================================================================================================
On 04/06/2009 15:19, ak2b posted:
Even after I lowered the input to the amp I was still seeing the SWR climb sometimes when I keyed. I put the 5W amp into a double sided PC board box and now all is good. With 13.8V and +1 Dbm input I'm getting about 6 watts out. The T/R switching using the Pin Diode Switch works very well. I am driving the amp directly from the DDS output switched from another PDS. The ouput of the DDS is +7 Dbm. I don't see any need for the BPF on the output of the DDS and without it it will be less complicated to switch bands.
I am pleased :). Now I have a complete TX module that can be used with the other rig I was working on.

I worked Sweden this morning even with some bad local storm QRN.

[img]http://tomnyc.no-ip.org/images/5WtxBox.jpg[/img]
=====================================================================================================
On 04/06/2009 15:52, ak2b posted:
[aa4w wrote:] "It looks like great fun! And a reason to melt some solder."


Hi Rick,
Welcome aboard.
If you have enough modules built, it's like Lego Radio.

Tom, ak2b
=====================================================================================================
On 04/15/2009 17:06, AA4W posted:
Tom,

I've been building along and am working on the diode mixer. I have a question. I think I know tha answer but you are there so I'll pick your brain. Diz supplies resistors for a 3db pad at the LO input but I'm using the Universal VFO, to start, since the output of the VFO is variable I'm thinking I don't need a pad at this time. Am I thinking correctly?

By the way, installing the SMD diode ring was sort of like putting a cast on a new-born fleas' leg! But all went fine. ;-)

Rick
A4W
=====================================================================================================
On 04/16/2009 11:53, ak2b posted:
Rick,

You are thinking correctly, it will work fine without the pad.
SMD's are a problem at first but the key is tiny solder, tweezers and a clean tip. I prefer working with SMD's over leaded parts but it took some time getting used to.

Tom, ak2b
=====================================================================================================
On 04/16/2009 15:26, ki4mmm posted:
One nice thing about SMT's is that if you get too much solder on them, it is easy to suck all the extra off with a copper solder-wick. I almost always blob too much on a few pins of the little IC's, but the excess wicks right off like magic.

Greg
ki4mmm
=====================================================================================================
On 04/20/2009 08:42, AA4W posted:
Well, I have been moving right along with getting the boards assembled. 'only have the BPF and IF Amp to go. The weather has been TOO nice to pass up a couple of fishing trips this week! But it looks like rain, today, so I'll have some tome in the shack. I have assembled a nice test jig to mount the boards on...made from double sided circuit board material. I ordered the Ver 1.1 of the RF Amp, this morning, so I have all the boards to begin 'playing', once they are assembled.

I think I have figured out the 'trick' to assembling the connectors. I assumed the pins should just slip in but they haven't been that easy. ;-)

Rick AA4W
=====================================================================================================
On 04/20/2009 13:03, ak2b posted:
I don't crimp mine, I solder instead. If you look at the pin from the side with the crimp part to your left you will see two triangle shapes at the very end. I clip these off. Very lightly tin at that point as well as tin the wire - and carefully solder the wire so it mates to the pin without rising above the highest edge. It helps to have a pair of hemostats to clamp the pin while soldering. If all is well, the pin should slide easily into the shell until it clicks.
Crimping those tiny pins makes me crazy (crazier) :).

Tom, ak2b
=====================================================================================================
On 04/20/2009 21:10, AA4W posted:
Oh I am soldering them...it's just that I expected them to slide in an click, much easier. But I have them under control, now.

I'm finished building the boards and am building the cables, now. And I discovered that I did order a set of filter crystals but neglected to order the rest of the crystal filtyer kit! So, in ther AM I'll be sending another order in to Diz! LOL!

On the crustal filter instructions Diz mentions for a 500 hz filter to use 470 pf caps. I just happened to find a handful of 470 silver micas the other day so I plan to build it that way. (besides I don't have any good caps at a lower value)

Rick
=====================================================================================================
On 04/23/2009 09:30, ak2b posted:
I put the Audio Amplifier, Memory Keyer and the NESCaf into one box to give some isolation to the audio section and the various keying and voltage lines. I'm not sure how much this will help at this point since I've yet to test it. I was getting a little extra noise on my side tone when keying. In any case I like making PC board boxes and in the long run I won't need to be so concerned with stray RF from unwieldy wiring :).

Tom, ak2b
[img]http://tomnyc.no-ip.org/images/audiobox.jpg[/img]
=====================================================================================================
On 04/23/2009 12:51, ki4mmm posted:
Tom , it looks nice! Quick question - I can't quite see, and it isn't registering with my brain if it is obvious, but what are you doing for the pass-through's in the front panel (i.e., what type of connectors are those)?

Greg
ki4mmm
=====================================================================================================
On 04/23/2009 13:34, ak2b posted:
Hi Greg,
The wires going along the bottom of the picture are soldered to feed through capacitors which are on the back of the box. The black ground wires are soldered on both sides of the back cover through a drilled hole.
The controls on the front of the box are from left to right are:
IF gain to the HYCAS IF/AGC board, AGC on/off, NESCaf passband width control, NESCaf on/bypass, and NESCaf passband shift pot.
Just above the Memory Keyer board is the volume control. Unseen in the picture are the paddle jack, the headphone jack and six memory swithchs for the keyer.
I'll post another picture later when it's all working and mounted in the transceiver.
Hope that clears things up.

Tom, ak2b
=====================================================================================================
On 04/23/2009 13:55, ki4mmm posted:
Ah, feed-through caps - that is what I wanted to know, and that is what wasn't registering in my brain (because I haven't used them before) - thanks!

Greg
ki4mmm
=====================================================================================================
On 04/26/2009 14:21, ak2b posted:
I'm not having a real happy weekend. I couldn't get the NEScaf to work correctly. When I adjusted toward the widest bandwidth it sounded muffled instead of like it should at maximum bandwidth. So I pulled the board to test it and a test lead fell on it and blew up the 9 volt regulator. There was lots of flame and smoke :).
After that happened, I got the idea to try the other filter (already built and in its own metal box) on the output of the GC Audio Detector. The NEScaf already has am LM386 so why use another? The gain for the filter is from a PC 10K pot but that can be substituted with a regular panel mounted one. It worked really nice Ė a lot less hiss and sounds great. Not an abundance of audio like before but still enough to easily get the job done. So, after I get another 7809, that's what I will do.

Some days nothing goes right. Time to take a walk in the park.

Tom, ak2b
=====================================================================================================
On 04/26/2009 14:32, jaswarb posted:
What value are the feed thru capacitors you have used Tom?

Jim NS5U
=====================================================================================================
On 04/26/2009 18:22, ak2b posted:
Hi Jim,
[jaswarb wrote:] "What value are the feed thru capacitors you have used Tom?"


Well they are not ideal for HF. They are 1000pf. They will attenuate RF at 14Mhz about 32db. They are more useful at VHF and up. But they were cheap and they make a decent tie point if nothing else :).
I got them from http://www.danssmallpartsandkits.net/ a little over half way down the page.

Tom, ak2b

P.S. I put .1uf on the feed thru's where necessary
=====================================================================================================
On 05/25/2009 10:25, ak2b posted:
I'm still here. I had a bout with the flu the last couple of weeks. I'm fine now and just finished another NEScaf after blowing up the other one. I plan to put it in the same enclosure with the keyer. I'm leaving out the audio amp and feeding the NEScaf from the product detector and using an external 10K pot instead of the one on the NEScaf for the primary volume control. A preliminary test sounded pretty good.
Iím also having Road Runner speed problems (only about 56K) so my pictures are probably taking forever to download. They are supposed to be here this afternoon to fix the problem.

Tom, ak2b
=====================================================================================================
On 06/15/2009 10:57, ak2b posted:
[img]http://tomnyc.no-ip.org/images/tx-rxcomplete-backview.jpg[/img]
=====================================================================================================
On 06/15/2009 14:43, ak2b posted:
[img]http://tomnyc.no-ip.org/images/rx.jpg[/img]

At the moment I can use 20 and 17 meters by changing the jumpers on the low pass and the bandpass filters. Eventually I will use the three position switch on the front panel to do band change. The FCC-1/2 has band select pins that can be set with the same switch and some diodes. Also, as far as I know, this is the only way you can change low side or high side injection on a per band basis.
The transceiver works very well with no anomilies (knock on wood). Building in the SCAF and using it for audio output has worked out very well. It is fed directly from the Gilbert Cell Audio Detector.
The memory keyer is excellant. I thought originally that I would use a pot to control speed but gave up on that when I realized you can change speeds very quickly by holding the command button and immediately sending a dit or a dah for higher or lower speed changes at 2 wpm.
I finally wired up the IF gain pot and AGC on/off switch for the HYCAS board. Although the AGC is very good there are times when it has to go. The receiver sounds more 'alive' wihtout it (but, keep a hand on the IF gain pot) :).
Even though most of the boards are boxed it hasn't been that much of problem if I need to get in one and make changes.
At some point I may box up the other boards but for the time being, since there doesn't seem to be any interactions, I will leave as is.

Where is everyone?

Tom, ak2b
=====================================================================================================
On 06/16/2009 01:25, W4GNS posted:
I'm still here Tom. But I fell out in Kentucky on 03/01/2009 with major back/neck injuries.(trucking has destroyed my spine) Family got me back home after a week in the hospital. Going through the ringer with test and surgery. Not up to sitting and slumped over doing any soldering.And pain killers make it hard to concentrate. But hope to be back in the click in a few months, but I do keep an eye on the forum. And enjoy other folks post here and other email reflectors. I did order some more 'roids from Diz this weekend and will try to play around with some baluns, slowly but surely. Keep these guys posting Tom, And later I will be here asking LOTS of questions ! ! ;-)

73 Gary W4GNS

[ak2b wrote:] "Where is everyone?

Tom, ak2b
"


=====================================================================================================
On 06/16/2009 15:20, ak2b posted:
Hi Gary,
Sorry to hear that you are laid up. Back/neck problems are never any fun.
Get better and I hope to see you hanging around here as soon as you feel up ot it.
Tom, ak2b
=====================================================================================================
On 06/21/2009 08:38, ak2b posted:
ALL ASIAN DX CONTEST

I can hear them but sometimes 5 watts just isn't enough.
This receiver hears very well. I heard several JA's Sunday morning. Friday evening, at the beginning of the contest I was able to work 4 Asiatic Russians. This contest is interesting because along with a signal report, you give your age. Most ages I heard were in their 60's and 70's. The first Russian I worked gave an age of NN which I presume is 99.

http://tomnyc.no-ip.org/audio/jh7uyb.mp3 (263KB)
I like to use the scope visualization when listening to recordings of cw. If the cw is fast enough, you can see the keying envelope.
Like: http://tomnyc.no-ip.org/audio/VVV30.mp3http://tomnyc.no-ip.org/audio/jh7uyb.mp3 (50KB)
If you're using Windows Media Player:
Click on:
'Now Playing'
'Visualizations'
'Bars and Waves'
'Scope'

Tom, ak2b
=====================================================================================================
On 06/29/2009 10:59, ak2b posted:
FIELD DAY 2009

http://tomnyc.no-ip.org/audio/FD2009SatShort.mp3 800KB
I don't care much for my sidet tone. I've been trying to shape the side tone output of the keyer but haven't had much luck. The waveform is not quite a sine wave as you can see if you use the scope described above. I built up a Twin-T oscillator a while ago and clipped it in briefly to see if it sounded ok. Both the Twin-T and the sidetone of the memory were on at the same time and it sonded pretty bad. After I took out the oscillator I realized that the keyer has a command to kill the internal sidetone. I pulled it also for the noise thump created by keying the 12 volt line of the oscillator. I'll give it another shot soon.
I continue to be impressed with the memory keyer despite the side tone issue. There are commands for everything it seems. There is a very convenient 'M' command to turn off the TX keying so you can use the keyer as a code practice oscillator or in my case while I was trying to shape the side tone. Actually, I used the 'M' first and then the 'T' (transmit) to get a continuos tone. I found other commands for getting just the right timing while use iambic B mode. I haven't found the need for the keyer pot since holding the command button while hitting a dit (increase speed) or a dah for decreasing speed is so simple. There is also a diagostic command for testing the memory buttons. This I found the hard way because initially I was getting memory errors. I e-mailed Mr. K-12 and he told me to try the 'Y' command which reads back a number with each switch press . I later found that I had a groud problem caused by not joining the inside with the outside of the double sided PC board box :). I loaded up the memories with contest info during FD and it worked great.

Tom, ak2b
=====================================================================================================
On 07/04/2009 15:28, ak2b posted:
I put up the 40 Meter Parts and Kits video on YouTube. This isn't anything new if you saw the one posted here.
http://www.youtube.com/watch?v=AB3x48o10bo

Tom, ak2b
=====================================================================================================
On 07/05/2009 03:30, wa8qfe posted:
Just watched ur video..the rx sounds good !
Your bench looks like the table in my hotel room. I'm /9 in Indy now.
How about a comment on the xtal filter in the video ?
I'm playing with MVAM109's in mine.
73 es DX,
Lee, WA8QFE
=====================================================================================================
On 07/05/2009 06:57, ak2b posted:
[wa8qfe wrote:] "Your bench looks like the table in my hotel room. I'm /9 in Indy now.
How about a comment on the xtal filter in the video ?
I'm playing with MVAM109's in mine.
"


Hi Lee,

On page 3 you can see the same crystal filter as in the video.

Tom, ak2b

P.S. My bench used to be my dining room table :)
=====================================================================================================
On 07/11/2009 21:30, ak2b posted:
Another You Tube Video\
http://www.youtube.com/watch?v=ECAKDGm0sYY

This is a semi finished transceiver but very usable as is. There are a few odd ball things that arbitrarily occur but I'm closing in on them :)

Tom, ak2b
=====================================================================================================
On 07/15/2009 04:48, wa8qfe posted:
Tom,
Watched your newest video...gud job.
I ordered a Hycas and I think I have the last through hole NEScaf on it's way now. After I ordered it, they posted a note that the last was shipped the 12th and the new run will have a SMT chip, available in a few weeks.
I'm trying the N3ZI DDS VFO with the NE602 mixer, but will use DIZ's Amp to drive the ring mixer soon..
I'm doing pretty good in a non-smoking (solder included ??) hotel room, but your way out front.
Keep up the great work, and thanks for sharing with us all !!
72/73
Lee, WA8QFE
=====================================================================================================
On 07/15/2009 12:56, ak2b posted:
Hi Lee,
Thanks for the video comments.
Interesting about the NEScaf. I wonder if the whole board will be smt or just a chip or two?
I haven't used N3ZI's DDS VFO but heard good things about it. I like that you can control it via RS232
[wa8qfe wrote:] "I'm doing pretty good in a non-smoking (solder included ??) hotel room, but your way out front."


If you ever think about adverse working conditions, think of Gary, W4GNS :).
http://www.w4gns.com/trk.html

Tom, ak2b
=====================================================================================================
On 08/02/2009 19:28, ak2b posted:
[url]http://www.youtube.com/watch?v=dy4YEf3hHcY[/url]

I put up another video on You Tube which shows the HYCAS board installed in a test bed receiver. I have two boards. I pulled the other one out of the transceiver for comparison and found them very close in performance.

Tom, ak2b
=====================================================================================================
On 08/04/2009 16:45, wa8qfe posted:
Tom,
What value did you put into R5 on the Hycas Board, or did you jumper it ????

lee, WA8QFE
=====================================================================================================
On 08/05/2009 09:58, ak2b posted:
[wa8qfe wrote:] "What value did you put into R5 on the Hycas Board, or did you jumper it ????"


Hi Lee,

I jumpered R5.

I also ordered an N3ZI DDS VFO. How did you make out with yours?

Tom, ak2b
=====================================================================================================
On 08/06/2009 06:28, wa8qfe posted:
Tom,
I went so far as to get another N3ZI DDS VFO, (my third) this one he only offered pre-built as it is a over clocked version.
The DDS chip was a bit of a shock to my 59 year old eyes, but went well on the 2 I built.( 1 is for my HW9 and 1 for my Sierra.)
In the over clocked version he only went to 80 Mhz, but I read it could go to 100 Mhz.
With DIZ's NE602 mixers it seems good, but with the ring mixer I'll be using DIZ's HF amp or the TenTec MMIC Amp as the DDS output
is low.
I've just been playing with RF tool kits and I have a hotel room full of un-started projects..including a Electroluminescent RX, a 2N2-20,
a OHR wattmeter...and more. This weekend I'll not solder and fire the K1 up for a change.
My Hycas and the NesCaf are complete and I received a TenTec 1000A case for the NesCaf today. (They are on a clearance sale.)
73 es DX
Lee, WA8QFE
=====================================================================================================
On 08/06/2009 06:46, wa8qfe posted:
Tom,
The reference to 80 and 100 Mhz is the clock oscillator....I haven't tried the overclocked version much above a 6 meter output.
On his site, N3ZI recommends DIZ's amp to drive a DBM.
I work 4 days of 10 hours...so 3 days off to home brew, now the xyl is here so no need to make the 7 hour drive to Missouri so often.
Lee, WA8QFE
=====================================================================================================
On 08/07/2009 13:12, ak2b posted:
Hi Lee,

I haven't gotten my N3ZI DDS yet. I know what you mean about soldering the chips, though. It took me a while but I got pretty good at it using the cooking method ( heating the board on a hot plate and then using a heat gun). I'm 63 years old and have floaters in my eyes larger than most of those chips :). A magnifying lamp is a must.
I saw no where in the DDS documentation that mentions going from RX IF frequency to TX direct frequency. I wonder if I missed something?

Tom, ak2b
=====================================================================================================
On 08/11/2009 16:54, wa8qfe posted:
At work we have IR heat guns that wouldn't blow the chip away, but there I would have trouble getting a board through security or out.
Lee, WA8QFE
=====================================================================================================
On 08/29/2009 15:09, wa2mze posted:
This thread is an addiction. Got me off my butt and melting some solder. Just finished putting the last of the parts on my DDS-60 kit (and getting my eyes back in focus!). Placed an order with BG micro for some parts to build a controller for the thing. I'll be using an ATmega16 or ATmega32 for the job. BG micro has some nice optical encoders real cheap, https://www.bgmicro.com/index.asp?PageAction=VIEWPROD&ProdID=13071 , if anybody needs one. I also need to get to DigiKey and order some chip resistors and caps for the I0GLU DDS unit I'm also building. The AD9951 will make a better VFO since it has a 14 bit ACC instead of the 10 bit used in the DDS-60's AD9851 chip. As soon as I get the micro controller working with the DDS-60 I'm going to have to order a batch of stuff from 'DIZ (at least a bunch of toroids if nothing else). I have an 11"Wx15D"x6.5"H cabinet I found about 35 years ago at Leeds Radio that I always planned on building a transceiver in. Better late than never.
=====================================================================================================
On 08/29/2009 15:31, wa2mze posted:
[ak2b wrote:] "Another You Tube Video\
http://www.youtube.com/watch?v=ECAKDGm0sYY

This is a semi finished transceiver but very usable as is. There are a few odd ball things that arbitrarily occur but I'm closing in on them :)

Tom, ak2b
"


Your S meter pins whenever you transmit.
=====================================================================================================
On 09/05/2009 11:05, ak2b posted:
[wa2me wrote:] "Your S meter pins whenever you transmit."


It doesn't hit too hard so it doesn't bother me. In any case, I've pulled that transceiver apart and am in the process of building an SSB transmitter. So far I have converted a 'Gilbert Cell Audio Detector' board to a balanced modulator and am in the process of converting another of the same board to a transmit mixer (very little to do in order to make the conversion :)). I also made up a crystal filter for SSB that needs a little work. It's curve looks pretty bad and the bandwidth is a bit too wide. As soon as I can get it to work, I'll post pictures.
I've been bitten by the Bitx20 bug but don't want to just buy and build another kit. There is a lot of good info around among which is Leonard's videos http://www.golddredgervideo.com/kc0wox/. Through his video on the Bitx20 balanced modulator I was able to tell that my modified board was working just fine. Also, Google KD1JV and look at some his SSB transmitters for some very simple designs.

Tom, ak2b
=====================================================================================================
On 09/05/2009 13:33, wa2mze posted:
Looks like your current CW rig might morph into a K2 clone. But then you already have one of those...

My goal is to build a QRP SSB xcvr. I might use some of 'DIV's kits, or maybe just buy some toroids and parts from him
and build my own circuit boards. I found some SD5000 chips in the junk box that I bought from Newark electronics a few
years back, think I'll try building a RX front end mixer around this. Probably will start with 'DIZ's diode mixer design and
sub the SD5000 into it with some ideas from the 2001 HB. I'll have to wind two extra rf transformers for the LO input for
that.

I also have a bunch of 9mhz xtal filters I got at Dayton about 15 years ago. They are Gonset surplus that came out of
their 'sidewinder' VHF xcvrs. The filters 3.1khz bandwidth is a bit wide, but they are 8 pole filters with
sidewalls so steep it would take superman to climb out of them. IE: the ultimate rejection bandwidth 40db down
might be narrower than a filter with a 3db bw of 2.4khz. I have enough of these filters to cascade 2 or 3 of them
in the RX IF, so they may actually be good enough. I also could have one filter dedicated to the TX and and eliminate one or
two diode switches between TX and RX. Think I'll order a circuit board for the HYCAS if circuit, though I also have
a ton of CA2028 IC's I could use in an if strip. Other parts that I have in abundance in the junk box include over 100
DPDT 12v dip relays (for switching filters), lots of 1n4007 diodes (pin switches), T50-2 toroids (need to get
some -6 and -10 from diz), and lots of -43 balum cores (the .25x.5 size).

Finally I just finished building the DDS-60 from amqrp (haven't tested it yet) and need to build up a microcontroller
for it. I have a few MegaAVR chips (mega16 and mega32) so I'll be using one of those. Also have some sample
LED display controller driver chips from Maxim, one of which also will interface with a keypad.

I've got a very nice cabinet to build this into that has been sitting in the junkbox for over 30 years. Found that
at Leed's radio in NYC around 1975. It's about 8"x10"x15" and I've intended to build a radio into this box
since I got it. Just never found the 'right' circuit ideas till recently. I've been studying the schematics of the
K2 transceiver for ideas, as well as looking at what 'DIZ has.
=====================================================================================================
On 09/05/2009 18:34, ak2b posted:
I noticed in one of you previous posts that you ordered some encoders from BG Micro. Did you get them? The add says no hardware so I am wondering if you had any problem mounting the encoder? I assume they are just missing a nut for the shaft. I had order before from BG and got the same optical encoder but I had to remove it from a gimble type camera mount. I'm using it with my DDS-60.
It sounds like you have a high quality junk box. Keep us posted with your progress.

I decided to not use a whole 'Audio Detector' board up for a transmit mixer. I made up a simple circuit with just one of Diz's multi-purpose boards consisting of an SA612 and not much more. I'm getting a lot of good ideas for my SSB chain from the Epiphyte transceiver http://www.norcalqrp.org/files/Epiphyte3Mnl.pdf. Nothing is simplar than this and I like simple.

[img]http://tomnyc.no-ip.org/images/ssbchain.jpg[/img]

The TX mixer is missing the VFO input (very important) and the BPF hasn't been modified for SSB yet. The only things that work for sure at this point are the mic amp and the balanced modulator.

By the way, do you have a name. I looked up your call and couldn't find it so maybe you want to be anonymous :).

Tom, ak2b
=====================================================================================================
On 09/05/2009 18:59, wa2mze posted:
My order from BG micro came yesterday. I got two of the encoders (ya never know...). There are only two problems with them, both
are no big deal. The connector is very non-standard, but the wire is long enough to just cut the connector off and solder on a standard
one (or don't bother with a connector and just solder the thing to the pc board). The nut is missing, but it's a standard 3/8" pot nut, I
just borrowed one from an old volume control from the junk box and it fits fine. The shaft is very well damped so you won't be able
to give the knob a spin and let it ride, I think that's a GOOD thing actually (don't need the felt washer behind the knob like on the K2).

I'm sure that WA2MZE is listed on the ARRL website (last time I looked I still wasn't a SK). Name is Ken, QTH is Davie FL. (near FTL).


PS. Just looked at the Epiphyte link. Didn't think of using a CA3028 as a driver. Could add agc (alc) to it to control the power out,
they are using a pot, guess at low impedance that works at RF. Microphone amp is a 741. Those things are dinosaurs! (bet I have a
bunch in the junkbox) but I also have some more modern Fet op amps. Much less noise, but for this app it doesn't have to be hifi.
Last time I used 741's was in my ancient SSTV monitor: 5FP7 crt, 88mh toroids, etc. Still have the clunker, but it's no longer compatible with
anything on the air. Do have QSSTV on the Linux box though.... should hook that up.
=====================================================================================================
On 09/06/2009 13:06, ak2b posted:
This recording is the SSB TX chain as shown above with the exception that the LPF is not being used. The output of the TX mixer (bottom connecter) has a wire acting like an antenna attached to it. I added the VFO input connecter to the SA602 and use the FCC-1/2 at about +7dbm to feed it. The microphone is an old Panasonic electret from a cellualr hands free kit - which is why it sounds like it's being handled too much. The Epiphyte speech amp has the bias for this. The recording is from the earphone jack of the K2 with antenna attached - which is the reason for all the background noise. I know I could make a better recording but at this point I have more important fish to fry - like boosting the output power of the TX mixer and deciding whether to modify the LPF I already have or make up a new one. Over-all I'm amazed that I got this far :)

Tom, ak2b

http://tomnyc.no-ip.org/audio/SSBtxTest.mp3
=====================================================================================================
On 09/07/2009 21:41, ak2b posted:
[url]http://www.hellocq.net/forum/attachment.php?attachmentid=152219[/url]

While Googling around I found this transceiver from Dave Benson. It had just what I was looking for in a post tx mixer amp and BPF, so I lifted it verbatum and made the following board. In hindsight it would have been wiser to put the amp on the mixer board. I have enough room on the BPF board to build another BPF for 17Meters.
At this point when feeding the mic input with the *Elecraft 2-Tone generator I have about +2dbm on the output of Diz's RF amp. I just need to dress the leads a little better to get rid of some hum and figure out some cheap an dirty keying circuit - an I'll be on the air with SSB :).

[img]http://tomnyc.no-ip.org/images/TXmixerBPFamps.jpg[/img]

Dave Benson's transceiver looks like it would work really well.

Tom, ak2b

*stick a cap on the output of the generator since there is DC bias for the elecret on the mic connector.
=====================================================================================================
On 09/09/2009 15:46, ak2b posted:
Well, I thought I was close to getting on the air :). I have a few more problems, obvious now with the added gain.
Last night while transmitting with the exciter and listening to myself on the K2, I could hear some decent sounding SSB. But, tuning away from where the SSB sounded best, produced a noise that sounded like a choir of cats. I had no idea what the problem was. I also realized that I didnít quite know what I was doing. After doing some reading http://www.arrl.org/tis/info/bldgeqp.html ĎThe principles of building SSB gear (part 2)í by Doug DeMaw, I found that my carrier oscillator should be at 5.065.500 MHz (1.5 KHz lower) if my crystal filter center frequency was 5.067.000 MHz (for USB). This should put the carrier frequency about 20 dB down on the skirt of the crystal filter for adequate carrier suppression. My crystal filter is so messed up that finding the center frequency through the ripple is going to be difficult. In any case, the BW is way too wide so the whole filter needs to be redone. The caps Iím using are 39pf but I think 49pf is more like it. Properly terminating the filter might also help. Hopefully a better filter will chase the cats away. Or, I might end up using a 9 MHz commercial filter that I have on hand.

Tom, ak2b
=====================================================================================================
On 09/09/2009 19:12, wa2mze posted:
You probably want get a good scan of what the filter BW looks like in real time. You know, a sweep oscillator driven by a sawtooth wave
also driving the X axis of your scope while you look at the filter response on the y axis. Bet you have some test equipment like that.
Then replace those caps in the filter with some trimmers and you can tweek them in real time while watching the scope. Should be able
to get it perfect then. Just make sure your filter is terminated with the right impedance at BOTH ends while aligning it.
Also you might not have your crystals in the filter matched well enough to even bother, though in that case some trimmers in parallel with the
crystals might compensate.

If you give up on the homebrew filter, or just want to eliminate it as the problem try subbing that store bought filter in and see if it works any
better.

I've got my AVR16 micro up and running (at least it's passing the 'hello world' test out the serial port). Next step will be to write a
serial driver for the DDS-60 and see if I can get it to spit out some RF, say at 10mhz. Then I'll add a user interface via the serial port
so I can control it. I also think I'll look for a d/a converter to output a sawtooth sweep so I can build my own sweep oscillator and sync
it to my TEK454 so I can test MY if filters and see if they are any good. Guess I'll be trying to beg a free sample from Maxim-ic for the
d/a. (there was a nice article in QEX a year or so ago on building something like this).
=====================================================================================================
On 09/10/2009 11:37, ak2b posted:
Hi Ken,
I have an N2PK VNA (which has a very steep learning curve for me). The filter looked pretty bad. I really didn't take my time with it. The crystals Diz sent were right on the nose, frequency wise. I checked them before I built the filter. I used the AADE filter design program last night and it actually didn't look so hot either using the Min-Loss (Cohn)type Ladder design (using all the same caps that I used). Using a Butterworth design looked a bit better. I'll give it another shot using your suggestion of adjusting parallel trimmers while sweeping.

I probably will try the Inrad filter since I also have the 9 MHz USB and LSB crystals. At least I will find out if everything else is working ok.

There is a group at http://groups.yahoo.com/group/dds_controller/ which has a program for controlling a variety of DDS's including the DDS-60. The group started out with the idea that serial ports are disappearing and they wanted to be able to control a DDS-60 via the USB port. I believe the program is still available although the group has gone on to other, newer DDS chips. The programs should still work with the DDS-60.
Steve Weber, KD1JV http://kd1jv.qrpradio.com/butterfly/bflydds.HTMhttp://groups.yahoo.com/group/dds_controller/ uses the AVR Butterfly to control a DDS-60.

Tom, ak2b
=====================================================================================================
On 09/12/2009 16:17, ak2b posted:
After spending half the morning trying to measure crystal parameters with my VNA, I gave up and did it manually from the "BW/Q method of parameter measurement" on this page:
http://pages.suddenlink.net/wa5bdu/crystal_slide_show.pdf

[img]http://tomnyc.no-ip.org/images/crystaltestset.jpg[/img]

While changing the VFO frequency the output of the crystal was measured directly with the M3 until a peak was found. Measuring crystal peaks is not so easy since there is some point around resonance were the frequency doesn't change so sharply. This is not the case, however, with the -3db points - they are more distinct. You can figure out the resonant frequency as the center of these -3db points if you like.

I measured 5 of the last crystals that I got from Diz with these results:

Fs -3db low -3db high Rs BW
5.067.211 5.067.167 5.067.255 12.8 ohms 88
5.067.224 5.067.194 5.067.266 15.4 ohms 72
5.067.226 5.067.184 5.067.277 19.6 ohms 93
5.067.220 5.067.171 5.067.265 14.6 ohms 94
5.067.202 5.067.159 5.067.257 15.0 ohms 98

Which is quite a good match as far as I'm concerned.

So, from the formulas on the above mentioned page I got from the first crystal the following:
QL = 57.582 Cm = .0144pf Lm = 68mH and Co = 3.16pf

That's enough information for AADE's filter design program.
If anyone finds something strange about thes figures, please let me know. I'm very new at this.

Tom, ak2b
=====================================================================================================
On 09/12/2009 19:56, wa2mze posted:
Now that's interesting. A few years ago I snagged about 250 8.3886mhz rocks in HC6u cans off of fleabay.
I'd sure like to try making a few IF filters out of them. I've been told crystals in these larger cans make better
filters than the sub mini micro processor rocks, not too sure if that's true but it could be.
IIRC I paid about $15 plus postage for all those rocks.
=====================================================================================================
On 09/13/2009 15:46, ak2b posted:
[img]http://tomnyc.no-ip.org/images/ssbfiltermix.jpg[/img]

I transformed the 2K input/output impedance to 50 ohms so I could sweep it with the VNA. I used Jack Smith's tutorial in the AADE Filter Design program Help Files. Having done that, I added something that likes 50 ohms - the ADE-1 mixers which are those little things at each end of the filter. The ADE-1 is supported upside down by the ground leads.
http://www.danssmallpartsandkits.net/ is selling ADE-1's for $6.00 with a little circuit board.
Anyway, the curve looks fine but the slopes stink. I don't know if this is a problem with the design, the VNA, me or all three. The slopes are only good to about 40 dB. I took out another filter (Inrad) and tested it with the VNA and it also has poorer slopes than it should (not quite as bad as mine, though).

I'm taking a break - the Giants are on :)

Tom, ak2b
=====================================================================================================
On 09/13/2009 16:49, wa2mze posted:
I see you have trimmers at half the capacitor positions. Depending on the filter design you might need to adjust the remaining cap positions to get your slope where you want it. The filter termination impedance can make a difference, as well as the number of poles (but five crystals does seem to be about the average used in SSB ladder filters.) If you use more poles you might need a series capacitor or two in the middle of the filter. Seems you are zeroing in on the thing though.....

I just got brave and hooked my newly built DDS-60 up to my ATmega16 development board. I wrote some software to initialize the SPI interface on the processor and to send bytes out to the DDS-60. I had to do some hex math to come up with the right constant to multiply the frequency by to get the correct DDS programming word. It has to be a binary fraction so that you can use integer math. The code is written in "C" using WINAVR (avr-gcc), the variables end up being long long int's (64 bit integers) and I right shift out the LS 24 bits to get rid of the fractional part of the product. Avr-libc DOES have a floating point package, but it's a code/cpu HOG.

Anyway my dumb program simply sets up the micro to dump 5 bytes of zeros to the AD9851 twice to make sure it's initialized in serial mode, then it calculates the DDS tuning word for 10mhz and sends that to the AD9851. I hooked up my frequency counter to the output, powered up the micro/dds and crossed my fingers. DANG!, either my counter is out of calibration or the rock on the DDS-60 is a bit off 'cause the output is 650HZ low! Well actually all considered, that's close enough for government work!

Next step is to hook up my shaft encoder and either an LCD display or an LED display. I have a module half built with 8 LED's and a MAX6954 display driver that I plan to use. The '6954 will also give me a 16 button keypad interface too. I may just hook up a 16x2 LCD just to have something now. I also can control the micro from my pc using the serial interface, and I'm using that now with printf statements to debug to code.

As soon as I have a way to change frequency on the DDS from a user interface, guess I'll hack up a DC RX front end.

AH HA, the A/C just turned on and started to blow. The frequency dropped another 10HZ. Well the DDS-60 isn't exactly THAT good a frequency reference I suppose.

PS, I'll drag the DSLR into the work room one of these days so I can post some pictures.
=====================================================================================================
On 09/13/2009 22:20, W4GNS posted:
Tom
Not sure if this is helpful but anyway here is a screenshot of the measurements I made last fall of the crystals I got from Diz using the W5BIG analyzer http://www.qsl.net/w4gns/dizcrystals.html Keep up the good conversation guys
73 Gary W4GNS
=====================================================================================================
On 09/15/2009 11:20, ak2b posted:
Hi Gary, I hope you're feeling better.
I remembered your post and looked it up to check my crystals against. They are very close.
Thanks,
Tom ak2b
=====================================================================================================
On 09/15/2009 12:29, ak2b posted:
That last board I built is kind of messed up. Both the ADE-1's are mis-wired. The audio input should go to pin 2 (IF) and pin 3 (RF) should go to the input of the the crystal filter. The output of the crystal filter should go to pin 2 of the transmit mixer.

Any resemblance to intelligence I may exhibit is purely coincidental:)
=====================================================================================================
On 09/15/2009 14:06, ak2b posted:
Hi Ken,
With all those crystals the only thing to do is make some filters. There are a lot of good references out there. Another one I like is:
http://www.k8iqy.com/testequipment/pvxo/Atlanticon2002V1R5.pdf
Once your DDS is done you aren't far from making one.
Tom, ak2b
=====================================================================================================
On 09/16/2009 09:07, W4GNS posted:
Tom
I'm looking at your K8ZOA crystal fixture, Is there anything special about that other than having alot of ground plane ? I soldered a female pin to a BNC connector when I was measuring, I need to whip something else up and get started doing something again. Gonna whip up a QRSS receiver, most likely from Hans Summers design, then get back to doing something with the RF Tool Kits, sloooooooooooly.

I have lost alot of stuff, that I had in the truck, last spring, do alot of hunting for by homebrew related stuff now, may have to reorder alot of the basics too, will make another post when I have gotten rolling on some cool stuff

And no Tom, not feeling any better, surgery did not help most of my symtoms, and the pain killers seem to be frying what few brain cells I have ;-( , I made a bad call when I thought it was a great idea to be a truck driver for a living. Really done a number on my back

73 Gary W4GNS

[ak2b wrote:] "Hi Ken,
With all those crystals the only thing to do is make some filters. There are a lot of good references out there. Another one I like is:
http://www.k8iqy.com/testequipment/pvxo/Atlanticon2002V1R5.pdf
Once your DDS is done you aren't far from making one.
Tom, ak2b
"


=====================================================================================================
On 09/16/2009 09:38, ak2b posted:
[w4gns wrote:] "I'm looking at your K8ZOA crystal fixture, Is there anything special about that other than having alot of ground plane ?"


Here is a schematic of Jack's test fixture. In the K8IQY url, there is also a test fixture. Take your pick. You seem to have gotten good results with your analyzer without a fixture.
http://www.cliftonlaboratories.com/Documents/Assembly%20and%20Usage%20Notes%20for%20Crystal%20Test%20Fixture.pdf
Sorry about your back. Good luck with that.

Tom, ak2b
=====================================================================================================
On 09/19/2009 20:44, ak2b posted:
After a futile attempt to get a decent curve out of the 5.067MHz crystals I gave up and built this 9MHz Inrad cheapy filter. The filter impedance is 200 ohms so I made up transformers with a 5 turn primary and a 10 turn secondary on an FT37-43 core. It looks pretty good. It looked really bad until I added the transformers. Actually, that might be a clue to why the 5MHz crystals look so bad - I probably have the impedance wrong.

[img]http://tomnyc.no-ip.org/images/Inrad9MHz2_7SSB.jpg[/img]

That's about all that went right today. I blew out one of the ADE-1's. Can't figure out how I did that.

Tom, ak2b
=====================================================================================================
On 09/20/2009 13:57, wa2mze posted:
Your measurement run on the Inrad filter looks like a carbon copy of the one on their website, except that
they had a center frequency 10hz lower than yours.

If you can drive your 5mhz filter from a high impedance output and put low resistance carbon pots on the
input and output of the filter, and measure with a 1meg ohm voltmeter, you should be able to vary the termination resistance
till you get it right. Problem is you don't KNOW what the correct termination impedance for your set of crystals should be
to get the right response curve, though I would have thought that within reason you could vary the capacitance till you
got it right for a given impedance. Maybe not if the crystal series resistance is too far out of wack. Did you look at the design of the filter in the K2 SSB adapter for ideas?

You might need to add a series capacitance at the input and output of the filter, or a series resistance at the input and
or output of the filter. I've seen these in some ladder filter designs, mostly those with 5 or more rocks though.

Anyway, that INRAD filter looks good, and for $24 not too bad. I'm hoping I can build something decent out of all those 8.3333 mhz HC6/U surplus crystals I have. As far as my project is concerned, I got the LED display board wired up with the MAX6954 display driver chip. Next step is to ohm it out to make sure I wired up correctly, then to add a connector to my Mega16 development board to interconnect the two and try writing a driver for it. Also need to wire up the rotary encoder and then we can actually try to control the DDS. I also need to find a serial interfaced D/A chip so I can generate a sweep output with the DDS, that will give me an el-cheapo way to look at the response curves for filters. Not actually right though since the voltage display on the scope will still be linear, not log ... would need a linear to log conversion circuit between the output and the scope. Could use the 10 bit A/D on the Mega16 and do the conversion and graph in software, but that would require writing a graphical application on the PC. Guess I'd have to look at the TCK/TKL, GTK or QT documentation (running Linux here) for that.

Also need to measure cutouts for the front panel of my project for the LED readout and the 16 switch keypad. Thinking of using a Dremel to cut out the openings. The target project box measures about 11"W x 6"H x 14"D (larger than the K3) which should give me plenty of room for the transceiver with a 100W power amp (though I'll start with something in the 10-30w neighborhood based on junkbox transistors I already have).
=====================================================================================================
On 09/20/2009 17:34, ak2b posted:
Hi Ken,
Thanks for the suggestions. I dismantled the 5 MHz filter with all the variable caps and tried using an SSB filter from Diz's kits with 39pf caps. If I model it with AADE I get about 600 to 700 ohms impedance. Anyway, I dispensed with the previous layout and now use the following one:

[img]http://tomnyc.no-ip.org/images/ssbtx.jpg[/img]

This setup is working really well. The DSB signal at the RF port of the SBL-1 is textbook. I'm using Diz's Universal BFO as the carrier oscillator. I threw caution to the wind and put the crystal filter in without the proper termination just to try the SSB chain as a whole. After the xtal filter I used the TX Mixer. I had to jumper past the pin diode switch since the following amplifier input is not at DC ground. I'm using an FCC-1/2 for the VFO. I tested the whole thing with a homebrew power amp and it works :). I'll get to the crystal filter termination some other time.

I'm looking forward to some pics of your DDS. I've never made an amp with more than a few watts. I'd be intrested in seeing what you do - particularly since sunspots have been few and far between.

Tom, ak2b
=====================================================================================================
On 09/21/2009 17:40, ak2b posted:
I modeled yet another filter using AADE filter designer. I pretty much followed the tutorial in the AADE help file - the one by Jack Smith. (Tutorials > Crystal Filter Tutorials > Cohn Filter Example) I even transformed the input and output impedances the same way it described in the tutorial. I used the 5.067 MHz crystal parameters described in anothe post on this page. I ended up transforming a 734.482 ohm impedance to 50 ohms. I built the L network into one of Diz's crystal filter boards. The caps are 39pf. The result is posted below.

[img]http://tomnyc.no-ip.org/images/DizsSSBcrystalFilter.jpg[/img]
[img]http://tomnyc.no-ip.org/images/DizSSBFilter.jpg[/img]



I think this will be good enough.
Tom, ak2b
=====================================================================================================
On 09/21/2009 18:32, wa2mze posted:
I've had a few ideas for a medium power final for the rig I'm working on:

Motorola design using MRF475 and MRF476 transistors (I have some of them)
http://www.datasheetarchive.com/pdf-datasheets/Datasheets-21/DSA-405884.pdf (figure 2)
Also the 40w mosfet amp that appeared in QST, but I'd run it at lower voltage at the 20W level....
http://www.farcircuits.net/rfpa2.htm#11rfpa

For a QRP final, probably a pair of 2N2219A's driven by a pair of 2n2222A's. These are 250-300mhz FT transistors and should give
somewhere between 1/2w to 2w PEP output. I have some fairly large TO-5 and TO-72 heat sinks for them.

Another idea would be a QRP final producing 2-5 watts (MRF476's) and an external linear using a pair of 1625 tubes. There was
a passive grid design in QST back in the '60's that used two 807W's with 1kv on the plates to produce about 150W PEP output (230W PEP input).
The 1625's are identical to the 807W's (except for a different base, 12.6v heaters, and larger ST16 glass bulb). These old bottles actually will take
the overload in plate voltage quite well.

If I go with one of the 20W finals, I might build a linear using one or two 811's to get up to 300W output (for those times when the band is REALLY
dead, or some rare DX shows up and I want the QSL bad enough.) I have a few 811's in the junk box too. There is also a real nice toroid power transformer available for around $60 that will power TWO 811's (including the heaters) that has a 240v primary. (OK it's a dual 550v secondary, dual 6.3v 5A, and is rated at 400VA at 50hz CCS. That translates to around 600VA ICAS at 60hz).

PS:
Just found a few of your videos on YouTube. Seems one of my ideas for an el-cheapo QRP final you already know of, and I just now heard of JBOT. Nothing new under the sun! I see you also have a DDS-60 based DSP in addition to the FCC-2. Which one do you think is cleaner? That DDS-60 package job reminds me of an old Lionel train power pack!

Well, I've started to work out in my head how to code the MAX6954 driver, maybe I'll get the LED displays going by the end of the week. Hope to package up my DDS-60 into a working VFO ASAP so I can get on to the FUN stuff. (Then I'll need to get some 74HC595's so the uC can control the BPF/LPF filter relays, though that's getting a bit ahead of myself!)
=====================================================================================================
On 09/22/2009 13:15, ak2b posted:
[wa2me wrote:] "Just found a few of your videos on YouTube. Seems one of my ideas for an el-cheapo QRP final you already know of, and I just now heard of JBOT. Nothing new under the sun! I see you also have a DDS-60 based DSP in addition to the FCC-2. Which one do you think is cleaner? That DDS-60 package job reminds me of an old Lionel train power pack!"


Hi Ken,
"The WB2EBY design is implemented in the PA-100 from HF Projects.
I can supply bare boards or kitted parts." (quoted from Virgil, K5OOR, the designer and owner of HF Projects)

I also have this kit, it is very handy to have around when 1 watt isn't cutting it.

The Motorola app notes also look interesting, particularly if you already have the transistors.

I don't know which one of the DDS's is the cleanest. I probably should. It has never been an issue in terms of practical use with any of the radios I've built. I know there are people that won't use either one because of the spurs. I haven't noticed them - I'm sure they are there, though. Maybe ignorance is bliss :). I can tell you that the DDS-60 is by far the hottest! The FCC-1/2 is incredibly well programmed to do almost anything you can dream up. Either one makes for a very cheap piece of test gear with great accuracy. I use my FCC-1/2 with a step attenuator as much as my HP8640B generator.

Tom,ak2b
=====================================================================================================
On 09/23/2009 19:47, kc0wox posted:
If you are looking for an amp, take a look at http://golddredgervideo.com/kc0wox/wa2ebyamp/index.htm

It documents building an amp to pump up your 1 watt.
Leonard
=====================================================================================================
On 09/26/2009 12:40, wa2mze posted:
Well I'm still working on the Mega16 controller. I hope to write some code for the MAX6954 LED driver interface this weekend. I got side tracked by another idea. I am going to add an IR receiver interface using a spare interrupt input on the processor. Since I already wrote this code for a project at work, getting it going on my DDS controller will be easy. So I will be able to use an IR remote control to operate the DDS and the eventual transceiver as well. I have a NIles R8 remote control (older version of this one http://www.nilesaudio.com/product.php?prodID=R-8%20L&recordID=ZR-6%20Multizone%20System&categoryID=Multizone%20Products&catcdID=2&prdcdID=FG01446) that I can use. The IR receiver interface is very simple, just a 38khz receiver module (http://www.bgmicro.com/index.asp?PageAction=VIEWPROD&ProdID=11069), connected to a spare interrupt on the microprocessor. The software uses a hardware timer to measure incoming pulses to decode the IR signals.
=====================================================================================================
On 09/28/2009 16:09, ak2b posted:
Well, I made my first homebrew SSB contact (ever) just a few minutes ago (19:45Z) on 20 meters with this setup :)

[img]http://tomnyc.no-ip.org/images/firstssbqso.jpg[/img]

I'm using the K2 for RX. T/R is done with an old DowKey relay (to the left of the K2) which is triggered with a toggle switch. The relay also supplies +12V to the *JBOT linear amplifier during TX. RX muting was done by turning down the volume control on the K2 during TX. In between the power meter and the DDS-VFO is the WB2EBY amplifier running about 15 watts output with a watt or so drive from the JBOT. I'm only using the amplifier on the BPF board (lower right) since the extra Power from Diz's RF amp wasn't necessary. Obviously this setup is subject to change. I want to try Diz's linear but took the easy route with the JBOT since it was easier to set up. I also want to try my DC receiver.

The QSO was with AC0BU, Carson who was in a bucket truck with a Yaesu and a Hamstick during the contact. Carson, in Corydon, Iowa said the signal was weak and that I sounded fine as near as he could tell - under the circumstances.

Ok, that was fun - about as much fun as ham radio gets.

Tom, ak2b

*JBOT by Ashar Fahhrhan http://www.phonestack.com/farhan/jbot.html
My JBOT Youtube Video at http://www.youtube.com/watch?v=rID2-uZrCgEhttp://www.phonestack.com/farhan/jbot.html
=====================================================================================================
On 09/28/2009 18:46, W4GNS posted:
Well Tom

You worked a mobile with 15 watts SSB ? That IS something to write home about. Congrads on the SSB contact and thanks for the pics
Gary W4GNS
=====================================================================================================
On 09/29/2009 11:27, ak2b posted:
[w4gns wrote:] "You worked a mobile with 15 watts SSB ?"


Hi Gary,
He kept signing mobile but somehow I had in my mind that he was in the bucket of the bucket truck during the QSO :).
I guess I was excited. Thanks for the comments.

Tom, ak2b
=====================================================================================================
On 10/01/2009 21:02, wa2mze posted:
Wonder if he had the antenna up in the bucket?

While I was looking for a microcontroller prototype board I forgot about these:
http://www.arduino.cc/
Real neat as you don't need a programmer, just download your program with a serial or USB cable.
It also comes with an extensive function library that makes handling the built in chip I/O easier, you
don't have to look up which bits in which register control which function. (I'm doing it the hard way,
still programming in C but at the chip level instead of the function level. Does give me more control
though.) The development software runs on Windows, Mac or Linux. I will probably adapt the Arduino
boot loader for my use so I won't have to use the ISP programmer in the future to update my firmware.
Still hoping to get back to writing the driver for the MAX6954 soon.
=====================================================================================================
On 10/02/2009 08:51, ak2b posted:
[wb2me wrote:] "While I was looking for a microcontroller prototype board I forgot about these:
http://www.arduino.cc/
"


Funny you should mention this device. I heard of it yesterday on the QRP-L list, looked it up and ended up ordering the Duemilanove board from Spark Fun http://www.sparkfun.com/commerce/product_info.php?products_id=666. I paid $30 for it. It looks like you can use it on any platform and the best thing about it is all the support. I'm not that good a C programmer but I think I can muddle by. Looks like a lot of fun.

Also, saw this on the QRP-L reflector this morning http://www.kkn.net/archives/html/QRP-L/2009-10/msg00011.htmlhttp://www.sparkfun.com/commerce/product_info.php?products_id=666
which looks REAL interesting. The good stuff is at http://openqrp.org/.

Tom, ak2b
=====================================================================================================
On 10/02/2009 14:17, W4GNS posted:
I have been playing around with the Picaxe http://www.rev-ed.co.uk/picaxe/ They are fairly simple and have alot of Docs that come with the free software and the Picaxe folks also have a VERY active forum. This may be too easy for you as you appear to have a "background" in such matters, but the Picaxe is great for those of us, who "ain't too swift" ;-)


[wa2me wrote:] "Wonder if he had the antenna up in the bucket?

While I was looking for a microcontroller prototype board I forgot about these:
http://www.arduino.cc/
Real neat as you don't need a programmer, just download your program with a serial or USB cable.
It also comes with an extensive function library that makes handling the built in chip I/O easier, you
don't have to look up which bits in which register control which function. (I'm doing it the hard way,
still programming in C but at the chip level instead of the function level. Does give me more control
though.) The development software runs on Windows, Mac or Linux. I will probably adapt the Arduino
boot loader for my use so I won't have to use the ISP programmer in the future to update my firmware.
Still hoping to get back to writing the driver for the MAX6954 soon.
"


=====================================================================================================
On 10/02/2009 20:11, wa2mze posted:
The picaxe looks like the basic stamp grown up.
Not a bad way to prototype things, but the performance won't be up to the arduino.
=====================================================================================================
On 10/02/2009 21:20, W4GNS posted:
Good Point, actually I bought an Aduino Duemilanove Board several months ago, and also a book, played with it awhile , but I tend to go back to the Picaxe for whatever reason. Maybe I had better finish reading the book and play around with it a tad more. C does not really appeal to me, but who knows. and I found this PDF file a few days ago, I found it to be good reading, the subject is making PCB's for SMT's and its super easy, for anyone interest http://www.vakits.com/datasheets/MakingSMTPCB.pdf

[wa2me wrote:] "The picaxe looks like the basic stamp grown up.
Not a bad way to prototype things, but the performance won't be up to the arduino.
"


=====================================================================================================
On 10/03/2009 12:19, wa2mze posted:
[W4GNS wrote:] "Good Point, actually I bought an Aduino Duemilanove Board several months ago, and also a book, played with it awhile , but I tend to go back to the Picaxe for whatever reason. Maybe I had better finish reading the book and play around with it a tad more. C does not really appeal to me, but who knows. and I found this PDF file a few days ago, I found it to be good reading, the subject is making PCB's for SMT's and its super easy, for anyone interest http://www.vakits.com/datasheets/MakingSMTPCB.pdf"


Looked at the pdf (yuck!). Well there are much better ways to make a PCB than using a sharpie for resist. I like the iron on method, using the toner from a photo copy machine or laser printer. There are special transfer sheets for this but many use glossy photo paper with good results (but lots more clean up after peeling off the paper). Also the common ferric chloride etchent is VERY messy. I now use a mixture of 66% Hydrogen-peroxide (drugstore strength) + 33% Hydrochloric Acid (that's common swimming pool muriatic acid). Pour the Acid into the H2O2 when mixing! This etchant is quite fast. Also it can be reused as the copper does not dilute the strength of the solution very fast.
=====================================================================================================
On 10/03/2009 17:00, ak2b posted:
Here is a short recording during the California QSO party. I made about 6 contacts with my SSB TX before recording this one. As you can hear, the CA ham can't hear me all that well. Some of the other contacts went much better.
I rigged up a foot switch to key the Dow-Key antenna relay, mute the K2 audio and supply 12 volts to the driver transistors on the JBOT amplifier. I muted the K2 by putting the radio in 'TX Test mode' and grounding the tip of the key jack during TX through another relay. Works well.

http://tomnyc.no-ip.org/audio/ssbcontact.mp3

Tom, ak2b
=====================================================================================================
On 10/04/2009 13:59, wa2mze posted:
How much power were you running during the 'test? Sounds like an after burner might be in order (unless your goal IS QRP that is).
I found an article in Feb QST for 1963 that looks like what I might eventually end up with here, driven by something like the JBOT.
I have a suitable power transformer and about a dozen good 1625's plus just about all the other required parts (think I might have to
dig up a pair of 0D3's). I still like messing with glass fets.

I dug out the spec sheet on the Max6954 so I now know what to stuff into the registers. Going to try to light up the seven segment readouts
next.
The Miami-Dade county hamfest was yesterday. It was so poorly attended that it wasn't worth the gas, tolls, and admission price.
But I did manage to find a nice brand new chassis, a PC board full of some nice slug tuned coils in cans (tunable BP filters?), and some
breadboard sockets. The former Motorola 'free-flea' is next month, hope it will be better attended than usual. Where have all the hamfest
attendees gone ... fleabay? (Or are they SK's?) At least Dayton was well attended this year (or so I heard from a few hams at work that were there).
=====================================================================================================
On 10/04/2009 16:46, ak2b posted:
[wa2me wrote:] "How much power were you running during the 'test? Sounds like an after burner might be in order (unless your goal IS QRP that is)."


Hi Ken,
I'm running about 15 watts or so depending on how loud I shout :). The JBOT is being driven lightly to put out about a watt +- into the WB2EBY (PA-100) amplifier - Just enough to keep things clean. I could drive the JBOT harder but then I could only get about 5 watts out - which isn't enough power barefoot and too much for the input attenuator that I have in the PA-100 (now that I mention this - I can't remember if the attenuator is set for 1 watt or 5). I know I could use more power but I have a lot of fun with the contesters who donít seem to mind - too much. There are a lot of really powerful stations on the air for the CA QSO party. Some of them had no problem with my pipsqueak signal while others did. Frankly, I don't see my future in SSB. I love cw - I just wanted to try and see if I could make an SSB rig. I may change my mind, though - it's a lot of fun to get on the air with homebrew ssb.

I don't go to a lot of hamfests mainly because there aren't any really good ones in this area. I think most part vendors have migrated to e-Bay. That's were I find most of the good off-the-wall things like 'S' meters and the mundane smd resistors and caps for really cheap.

Tom, ak2b
=====================================================================================================
On 10/04/2009 19:14, ak2b posted:
Well, here it is: SSB transmitter, the Video
http://www.youtube.com/watch?v=njo4Z_8cdWs
=====================================================================================================
On 10/05/2009 15:47, ak2b posted:
I got a QSL card today from Carson, AC0BU. Carson according to his Bio on QRZ.com is also a professional Cartoonist.
So for my hombrew SSB QSO I get a great homebrew QSL card :) Not a bad deal at all.

[img]http://tomnyc.no-ip.org/images/AC0BUqsl.jpg[/img]
=====================================================================================================
On 10/07/2009 13:40, ak2b posted:
I got my Arduino board yesterday and have been playing around with it. Setting up the software and hardware was painless. The website seems to have anticipated every idiot question I could ask before I asked it. Nicely done.
I went through the brief tutorials and really like what I see. On one hand the concept lends itself very well to the beginner but doesn't limit you if you happen to grow beyond the simpler concepts. It's easy to see why this devolpement package is so popular. Support seems to be everywhere.

Tom, ak2b
=====================================================================================================
On 10/08/2009 08:59, ak2b posted:
Hi Ken,
I found this link this morning. You might find it interesting.
http://blog.marxy.org/2008/05/controlling-ad9851-dds-with-arduino.html
I am going to try this myself. I think I will just hang a counter off the DDS-60 output rather than try and write code for an LCD (I don't think I'm up to that yet).
Tom, ak2b
=====================================================================================================
On 10/10/2009 15:29, wa2mze posted:
Tom, I'd like to post a zip file with the source code I'm developing for the mega16/32 driving the DDS-60.
I don't see how to post an attachment to this site though. I guess you post pictures by pasting them in, but I'm not
sure of that either.

The link you showed to the Arduino controller is a bit basic. I'm using the AVR spi hardware to talk to the DDS-60.
The Arduino library does have functions for the LCD driver with examples so it shouldn't be hard for you to get
an LCD up and running.

Here is my rotary encoder code, it is in C not wiring as in the Arduino, but I think it would work in the Arduino.

// encoder clocks are portb 2&3
#define phaseA PIND2
#define phaseB PIND3
//encoder states as seen at portb inputs
#define STATE_MASK 0x06

#define STATE0 0x00
#define STATE1 0x02
#define STATE2 0x06
#define STATE3 0x04

void init_decoder(void)
{
DDRB &= ~(_BV(PIND2)|_BV(PIND3)); //input pins
last_state = curr_state = 0;
dial = 0;
}

void decode(void)
{
curr_state = PIND & STATE_MASK; //read encoder

switch(curr_state){
case STATE0:
switch(last_state){
case STATE1:
if(dial < 127)
dial++; //increment dial
last_state = curr_state;
break;
case STATE3:
if(dial > (char)-128 )
dial--;
last_state = curr_state;
}
break;
case STATE1:
switch(last_state){
case STATE2:
if(dial < 127)
dial++; //increment dial
last_state = curr_state;
break;
case STATE0:
if(dial > (char)-128)
dial--;
last_state = curr_state;
}
break;
case STATE2:
switch(last_state){
case STATE3:
if(dial < 127)
dial++; //increment dial
last_state = curr_state;
break;
case STATE1:
if(dial > (char)-128)
dial--;
last_state = curr_state;
}
break;
case STATE3:
switch(last_state){
case STATE0:
if(dial < 127)
dial++; //increment dial
last_state = curr_state;
break;
case STATE2:
if(dial > (char)-128)
dial--;
last_state = curr_state;
}
break;
}
}


//interrupt on signal from encoder.
//call decode to increment/decrement dial
ISR(INT0_vect)
{
decode();
}

ISR(INT1_vect)
{
decode();
}


I've written code to receive input from a standard 38khz IR remote control. I'll post that later once I clean it up. It will
need to be made a bit more generic as it's currently coded to accept IR codes from only one make/model IR remote control.
It will work with any IR remote control based on an industry standard NEC controller chip, but it expects a specific vendor code.
(I work for Niles Audio, so I'm using a Niles R8 remote). But many vendors used this IR standard.


Here is the DDS code:
The frequency to DDS word calculation is done in integer math, I hand coded the DDS constant
as a binary fraction.

#include
#include
#include
#include
#include
#include
#include "uart.h"


#define DDS_LOAD _BV(PB4)
#define DDS_CLK _BV(PB7)
#define DDS_DATA _BV(PB5)
#define DDS_DDR DDRB
#define PORT_DDS PORTB

#ifdef DEBUGDDS
static char buffer[40];
#endif


// (2**32 / 180000000) + (rem of 2**32/180000000)*(2**24)
// generates a binary floating point number as an integer
#define Konst (unsigned long long)0x17dc65de

// perform a floating point mult of the frequency by the
// dds constant for 180mhz clock and a 32 bit accumulator.
// Integer math is performed and the fractional portion
// of the result is shifted away.
unsigned long CalculateDDS(unsigned long freq)
{
unsigned long long K = Konst; //(unsigned long long)0x17dc65de;

union dds{
unsigned long long Product; //64 bits
unsigned long Part[2]; //32 bits * 2
unsigned int i[4]; //16 bits * 4
}dds;


dds.Part[0] = freq;
dds.Part[1] = 0;

#ifdef DEBUGDDS
sprintf_P(buffer,PSTR("freq m->l %x,%x,%x,%x\r\n"),
dds.i[3],dds.i[2],dds.i[1],dds.i[0]);
uart_write(buffer,strlen(buffer));
#endif

dds.Product *= K; //multply freq by const

#ifdef DEBUGDDS
sprintf_P(buffer,PSTR("prod m->l %x,%x,%x,%x\r\n"),
dds.i[3],dds.i[2],dds.i[1],dds.i[0]);
uart_write(buffer,strlen(buffer));
#endif

dds.Product = dds.Product << 8; //shift left one byte

#ifdef DEBUGDDS
sprintf_P(buffer,PSTR("ret m->l %x,%x,%x,%x\r\n"),
dds.i[3],dds.i[2],dds.i[1],dds.i[0]);
uart_write(buffer,strlen(buffer));
#endif

return dds.Part[1]; //return upper long int as result
}


void spi_byte(char ch)
{
#ifdef DEBUGDDS
sprintf_P(buffer,PSTR("ddsbyte = %x\r\n"),ch);
uart_write(buffer,strlen(buffer));
#endif

SPDR = ch; //load spi to send a byte
while( (SPSR & _BV(SPIF))==0){} //wait for done
}

void send_dds_freq(char *freq)
{
//enable the spi as master, send LSB first, clock active high
//using F_CPU/16 (500khz), can go faster
SPCR = (_BV(SPE)|_BV(DORD)|_BV(MSTR)|_BV(SPR0));

PORT_DDS &= ~(DDS_LOAD); //bring load (cs) low
//send bytes 0-4 of the long word
spi_byte(freq[0]);
spi_byte(freq[1]);
spi_byte(freq[2]);
spi_byte(freq[3]);
//send the control byte
spi_byte(1);

//latch the data
PORT_DDS |= DDS_LOAD; //raise the load flag
}



void init_dds_spi(void)
{
//clear bits going to DDS
PORT_DDS &= ~(DDS_LOAD|DDS_CLK|DDS_DATA);

SPSR = 0; //clear SPI2X

//DDS bits are all outputs
DDS_DDR = (DDS_LOAD | DDS_CLK | DDS_DATA);

//enable the spi as master, send LSB first, clock active high
//using F_CPU/16 (500khz), can go faster
SPCR = (_BV(SPE)|_BV(DORD)|_BV(MSTR)|_BV(SPR0));

PORT_DDS &= ~(DDS_LOAD); //bring load (cs) low

//send 5 bytes of zero to DDS
spi_byte(0);
spi_byte(0);
spi_byte(0);
spi_byte(0);
spi_byte(0);
PORT_DDS |= DDS_LOAD; //raise the load flag

//do it again to make sure!
PORT_DDS &= ~(DDS_LOAD); //bring load (cs) low
spi_byte(0);
spi_byte(0);
spi_byte(0);
spi_byte(0);
spi_byte(0);
PORT_DDS |= DDS_LOAD; //raise the load flag
}
=====================================================================================================
On 10/11/2009 16:31, wa2mze posted:
Here is my code for the MAX6954 LED driver.
So far just the initialization and writing a frequency word to the display.
Still need to write the keypad input routines.

The frequency is displayed on the 7 MS digits of the 8 digit display, the LS digit
is reserved for a mode indicator like on the K2.


The MAX6954 shares the SCLK and MOSI lines of the SPI interface with the DDS-60,
different /CS signals are used. Also since the DDS-60 is LittleEndian and the Max6954 is
BigEndian on the SPI we have to re-init the SPI for each device before sending data.
Already taken care of in the DDS-60 code, and now in the MAX6954 code.

//
//LED, KB controller
//

#include
#include
#include
#include
#include
#include
#include

extern void spi_byte(char ch);

prog_char Decode7seg[] =
{0x7e, //0
0x30, //1
0x6d, //2
0x79, //3
0x33, //4
0x5b, //5
0x5f, //6
0x70, //7
0x7f, //8
0x7b, //9
0x77, //A
0x1f, //b
0x4e, //C
0x3d, //d
0x4f, //E
0x47, //F
0x0d, //value of 0x10 == "c" CW mode
0x0c, //value of 0x11 == "l" LSB mode
0x1c, //value of 0x12 == "u" USB mode
0x40, //value of 0x13 == "-" upper line on indicator
}; //decode array for seven segment

//Symbolic values for seven segment characters including
//mode indicators
enum SevenSeg{ZERO,ONE,TWO,THREE,FOUR,FIVE,SIX,SEVEN,EIGHT,NINE,
A,B,C,D,E,F,CW,LSB,USB,BAR}SevenSeg;
//the calibrate mode indicator is the same as HEX 0x0C display
#define CALIBRATE C

void spi_max6954(uint8_t reg, uint8_t val)
{
//lower CS for MAX6954
PORTB &= ~_BV(0); //PB0 is the CS for the MAX6954

spi_byte(reg); //register is MSByte
spi_byte(val); //val is LSbyte

//rasie the CS for the MAX6954
PORTB |= _BV(0); //PB0 is the CS for the MAX6954

}

void initMax6954(void)
{
int x;

//setup the SPI for BigEndian output
SPCR = (_BV(SPE)|_BV(MSTR)|_BV(SPR0));


spi_max6954(0,1); //no decode
spi_max6954(2,7); //global intensity
spi_max6954(4,1); //configuration
spi_max6954(3,7); //8 digits (scan all lines)
spi_max6954(6,0x80); //32 keys but only 16 are used
spi_max6954(8,0x0f); //4 keys of 8 on this line
spi_max6954(8,0x0f); //4 keys of 8 on this line
spi_max6954(0x0a,0x0f); //4 keys of 8 on this line
spi_max6954(0x0b,0x0f); //4 keys of 8 on this line
spi_max6954(7,0);//test register off

for(x=0;x<16;x++){
spi_max6954(0x60+x,0); //zero out all segments
}
}


//
//Display Frequency
//
// Input a long int, frequency in mhz
void DisplayFreq(uint32_t freq)
{
uint8_t digit, display, remain;
digit = 6; //displaying freq in 7 digits numbered from MS(0) to LS(6)

//setup the SPI for BigEndian output
SPCR = (_BV(SPE)|_BV(MSTR)|_BV(SPR0));

freq = freq / 10; //because we are NOT showing the 10's place
while(freq) { //continue until the freq is zero
remain = freq % 10; //display remain of freq;
display = pgm_read_byte(Decode7seg+remain); //convert to seven seg
if((digit==1)||(digit==4)) //add decimal point for MHZ and KHZ
display |= 0x80; //add decimal point
spi_max6954(0x68+digit,display); //write to display
freq = freq / 10; //reduce by 10
digit--; //next digit
}
//NO leading zeros, blank display
for(;(digit+1)!=0;digit--){ //remaining digits are blanked
spi_max6954(0x68+digit,0);// BLANK display
}
}
=====================================================================================================
On 10/12/2009 22:45, ak2b posted:
Hi Ken,
There is no way to post files to the forum directly. I do it by running a personal web server (IIS) on my XP Pro box and then run an app that reports my IP to no-ip.org. It used to be free but now I pay a few dollars a year. I used to have ak2b.com registered but keeping up a website is a lot of work. In any case my web server still runs locally and I just keep all the pictures and sound files in virtual directories and point to them from the FluxBB.
I looked at your code and want to give it a shot. I have a 9851 hanging around so I ordered another DDS-60 board to try out your code with. I'm also interested in the K1EL project with the Arduino. It seems Steve just got the transceiver boards in and is trying them out.

Ken, I think it is time to start another 'Topic' under 'RF Toolkits'. I'll let you have the honors since it is your code :) The DDS-60 is a excellant board and as far as I can tell there are no other controllers for it.

Tom, ak2b
=====================================================================================================
On 10/18/2009 01:57, W4DNQ posted:
Tom,
Got the VFO built and MAN what a diff.
That N3ZI DDS was only sending a 300mv signal to the mixer and Diz's VFO was over 1.5v.
It seems that the low IF I had was from the small signal from the DDS.

I ordered a bunch of Copper Clad board today as I am going to take somewhat the
same approach you did. It is getting to the point now that that there are just to many
wires all over the place. UUUHHHH !

Will keep all informed,
Ron / W4DNQ
=====================================================================================================
On 10/18/2009 12:01, wa2mze posted:
[W4DNQ wrote:] "Tom,
Got the VFO built and MAN what a diff.
That N3ZI DDS was only sending a 300mv signal to the mixer and Diz's VFO was over 1.5v.
It seems that the low IF I had was from the small signal from the DDS.

I ordered a bunch of Copper Clad board today as I am going to take somewhat the
same approach you did. It is getting to the point now that that there are just to many
wires all over the place. UUUHHHH !

Will keep all informed,
Ron / W4DNQ
"


If diz's diode mixer is typical it should need 7dbm input for the LO. At 50 ohms 7dbm is about 0.5 volts so that DDS is down
a bit less than half of what is required. 1.5v would be about 16.5dbm which would be over drive for the mixer, though
some mixers do require more than 7 dbm. Mini circuits makes mixers in the 7 - 17 (or more) dbm range.
To convert volts to dbm look here: http://www.sengpielaudio.com/calculator-volt.htm
=====================================================================================================
On 10/18/2009 16:07, kc0wox posted:
I did a web page on Diz's mixer. You can see it at http://golddredgervideo.com/kitsandparts/doubleballancedmixer.htm

I did some troubleshooting today on a bitx using my HP 8407a network analyzer. Boy, what a neat way to go. It's a totally different way of looking at things. I'll do a video using it as soon as I get better at using it.
Leonard
http://kc0wox.com
=====================================================================================================
On 10/19/2009 10:08, ak2b posted:
[wa2me wrote:] "1.5v would be about 16.5dbm"


Hi Ken,
I think Ron was talking p-p not rms since this is what Diz specifies in the last instruction for building the VFO.
[Diz wrote:] "Finally, adjust R5 for your output. 1.4V P-P = 7dBm"


Tom, ak2b
=====================================================================================================
On 10/20/2009 20:36, wa2mze posted:
[ak2b wrote:] "I think Ron was talking p-p not rms since this is what Diz specifies in the last instruction for building the VFO.
[Diz wrote:] "Finally, adjust R5 for your output. 1.4V P-P = 7dBm"


Tom, ak2b"


Makes sense. I didn't notice that the link I sent spec'd the voltage in RMS. Guess more people have scopes than RF RMS meters so they would measure in PP.
=====================================================================================================
On 10/26/2009 16:59, ak2b posted:
More and more I've started using the "Universal Generic PCB" for building projects. I would make one suggestion and that is to make the input/output 3 pin instead of 2 pin connectors. And along the side I would like to see at least one 3 pin connector for power.
I have no problem building with smd parts. The pad widths are just about right for a size 1206 cap or resistor. If you need to add two together you can mount an adjacent smd on the opposite side.
Anyway, this board is W7ZOI's bi-directional amplifier in response to the ones in the BitX20. If you read the article it pretty much sums up what this little amp will do. It is virtually identical in specifications to the aritlcle. After having built and tested this amp I will build up two more to use with my SSB transmitter to make an SSB transceiver :)
[img]http://tomnyc.no-ip.org/images/bisexualamptop.jpg[/img][img]http://tomnyc.no-ip.org/images/bisexualampbot.jpg[/img]
Tom, ak2b
=====================================================================================================
On 11/07/2009 22:07, ak2b posted:
I finished up two more bi-directional amps and added them to my SSB transmitter. I just tried to get it to receive and lo and behold it worked right off the bat :). Now I just have to make up the appropriate power cables to supply each module with 12 volts depending upon whether it used for transmit or receive. It is very close in concept to Ashhar Fahran's Bitx20 http://www.phonestack.com/farhan/bitx.html.
I changed the pictures in the previous post to reflect the updated boards. I got better at building the amps by the second board. I should have a working 20 meter SSB transceiver by the end of the weekend.

Tom, ak2b
=====================================================================================================
On 11/08/2009 10:32, kc0wox posted:
I see you are converted over to the I/O pins also. They sure make it easy to connect and disconnect from the board. I use them on all of my builds.

One great thing about the smd parts, they are really cheap.
Leonard
=====================================================================================================
On 11/09/2009 17:25, ak2b posted:
Hi Leonard,

Well actually I've used the headers all along. In fact I've re-ordered 3 times now thinking my last order would last forever :). I like smd's. Not only are they cheap but you usually get tons of each value - except .1mfd - where you I never seem to have enough.

Tom, ak2b
=====================================================================================================
On 11/09/2009 17:31, ak2b posted:
I finished the BitX20 style transceiver. I made a short recording of the receiver portion. The TX part works but I haven't had a QSO yet.
You will notice in short order that there is no agc. So, the recording starts out fairly quiet and builds to a crescendo at about 1 minute and 3 seconds into it. Don't say I didn't warn you!
http://tomnyc.no-ip.org/audio/birx1.mp3

Tom, ak2b
=====================================================================================================
On 11/09/2009 18:30, ak2b posted:
Behind this image is the power amp (from Dave Benson) and Diz's 20 meter LPF.

[img]http://tomnyc.no-ip.org/images/bidirtcvr.jpg[/img]
=====================================================================================================
On 11/10/2009 13:56, kc0wox posted:
I use the hex spacers also.

I mad a video last weekend testing a bitx20 version 3 lowpass filter, a wa2eby amplifier lowpass filter, and a 20 meter bandpass filter using my network amalyzer. The camera was goofing up and the focus came out bad so I won't put it up. I'll redo it in the next 2 weeks. The wa2eby amplifier filter, http://golddredgervideo.com/kc0wox/wa2ebyamp/index.htm had less than .1 db insertion loss. I was really impressed.
Leonard
=====================================================================================================
On 11/10/2009 14:45, ak2b posted:
I posted a vna scan of one of Diz's LPF's for 7MHz (Look under LPF) which has about the same insertion loss. Take a look. Does it look like your scan?
I did return loss scans and gain scan's on the W7ZOI bi-directional amps and posted them in the picture section of the emrfd yahoo group under my call. The results were dead on with the published specs. I still feel like a neophyte when it comes to the VNA so any feedback would be appreciated.
Tom, ak2b
=====================================================================================================
On 11/14/2009 15:08, ak2b posted:
[img]http://tomnyc.no-ip.org/images/D_Benson_amp.jpg[/img]
http://www.hellocq.net/forum/attachment.php?attachmentid=152219
I used this amp from Dave Benson's rig which is mounted in the back of the previous picture. It puts out 4 watts and is built on Diz's project board. The LPF is to the right for 20 meters.
Ta Da. I also made my first contact with this rig just a few minutes ago, 19:45:00Z with a station working a QSO party. I had been calling CQ all morning without any results but just happened to hear Larry call QRZ. It is a lousy recording because I wasn't expecting to work anyone - but did have the recorder going just in case.
The clunking in the background is the foot switch used to key the radio.
http://tomnyc.no-ip.org/audio/1stBitXQso1.mp3http://www.hellocq.net/forum/attachment.php?attachmentid=152219

Tom, ak2b
=====================================================================================================
On 11/14/2009 20:18, W8DIZ posted:
Tom....you are having WAY TOO MUCH FUN!
Speaking of fun, I'll be on a 7 day cruise out of San Juan P.R. next week
See you all in about 8 days.
73, Diz, W8DIZ
=====================================================================================================
On 11/15/2009 13:41, wa2mze posted:
What type of coax are you using between the boards? From the photo it looks like RG59U (looks like fat snakes in the picture!).
Except for the coax from the power amp to the antenna, RG174U should be good enough, and is a LOT easier to tie into
a wiring harness.
=====================================================================================================
On 11/15/2009 16:36, ak2b posted:
The coax is all RG174, which, for everything except very long runs, is really overkill. RG58/59 would be almost impossible to deal with. The photo was taken with a macro setting and the largest looking cable was very close to the camera.
=====================================================================================================
On 11/23/2009 09:22, ak2b posted:
I made another video called Bit-O-Bitx
The video url is http://www.youtube.com/watch?v=V_uBqbEV0-w

Tom, ak2b
=====================================================================================================
On 11/23/2009 12:45, wa2mze posted:
Those bi-directional amps do look interesting, it looks like each one is three stages. The bi-directional topology seems natural for a transceiver at first, but there are two problems. First, no receiver agc (or transmitter alc). Not even a place to apply manual gain control. Second, the required gain is NOT the same in both directions. In receive we need all the gain we can apply since we are starting out with microvolts or less of signal. In transmit however we are starting out with VOLTS of signal and only need enough gain to make up for losses in our filters, plus enough drive to saturate our final power amp to full output. So the bi-directional amps probably need fewer stages in the transmit direction than the receive.

I'm planning on using the hybrid cascade amp for the if in the receiver, and something more simple in the transmit stages. I'm not convinced that using the product detector as a balanced modulator is the best idea, though it would work without much fuss using the MCL packaged devices. I was thinking of a pair of MC1496's here, one for the PD and the other for the BM. These are older parts, but with careful bias adjustments and making use full of the differential inputs and outputs they can give good performance.
=====================================================================================================
On 11/23/2009 13:45, ak2b posted:
[wa2mze wrote:] "The bi-directional topology seems natural for a transceiver at first, but there are two problems. First, no receiver agc (or transmitter alc). Not even a place to apply manual gain control. Second, the required gain is NOT the same in both directions."


You are right on the first point - not quite right on the second. If you look at page 5 of Wes's article,
http://w7zoi.net/Bidirectional%20Matched%20Amplifier.pdf you will see a chart for resistor value changes per gain. I my case, I dispensed with such logic, threw caution to the wind, and just built it. I was shocked that I heard anything from the receiver at alll Transmit RF was just about right at 0DBm for my version of Dave Benson's amplifier. I would go back and change the amp ahead of the receive mixer if I were to do anything. I think 7db of gain is plenty for 20 or 15 meters. Yes, you will be rudely reminded very quickly that this receiver has no agc. However, if I had built this transceiver for top performance, I would have dismissed this design all together. Originally I built the ssb transmitter and was quite pleased that it worked. Naturally, I wanted to make it into a transceiver. I figured I would just complete the Dave Benson design (which is really quite a good one) using my Hycas agc/if amp and have done with it. But then I thought, well, I know it will be good, but the BitX with bidirectional amplifiers seemed more interesting. Here was a guy (Ashhar Fahran) who designed a rig with minimal parts so hams in other countries could easily duplicate it. Well, us yanks could easily duplicate it because parts are readily available everywhere. As a result, the BitX20 underwent a major overhaul and became a project that some of ham radios best engineers made refinements to. In any case the original idea has stayed in tact. I just wanted to give it the Diz spin. I knew from the beginning it wasn't the best performer in the world but then, neither is a direct conversion receiver. They still sound good. My version of the BitX sounds better and better every time I brag to someone that I built it myself :).

Tom, ak2b
=====================================================================================================
On 11/24/2009 15:14, wa8qfe posted:
Tom,
Bragging aside from our construction projects, the Bitx20a receiver sounds better than my FT897d.......well,
so does my K1 and Sierra. Both later rigs can be duplicated with diz's boards, and that's probably why I play with them. I have 2 Bitx kits from India and I'm sure they will sound good too, If I ever get started.
I finally finished my Hycas board, so onward to better things.
Lee, WA8QFE
=====================================================================================================
On 11/25/2009 09:21, ak2b posted:
Hi Lee,

Well, bragging is over-rated. My Bit-o-bitx isn't long for the world. I don't really like ssb but I wanted to see if I could do it. I learned a lot in the process. I want to get back to a cw rig maybe using another type of frequency control like a VXO. The nice thing about using modules is that it makes experimenting easy. I also really like building on the empty boards like the Dave Benson PA and the bi-amplifiers. The board is just about the right size for a VXO :).
I have taken a lot of good info from the K1 and K2. The schematics and circuit descriptions are a great source of information. Yesterday I just finished an SW20 from Small Wonder Labs. That is a clever little rig. I am now a big Dave Benson fan.
Lee, please keep us informed of your progress.
Tom, ak2b
=====================================================================================================
On 11/27/2009 16:27, wa8qfe posted:
Tom,
I think on one of your posts I saw you were using one of Diz's 10 watt amps....
Just want your input as to the impedance at T3. I want to omit everything from D2 for switching and omit
Q5 and all associated there. Looking to drive the buffer direct at the 1 watt level and 50 ohm input.
What do you think.....as is, my grid dip osc will drive it to full power.
Lee, WA8QFE
melting solder in Extended Stay America, Indianapolis
=====================================================================================================
On 11/27/2009 21:25, ak2b posted:
Hi Lee,
When you say that your GDO will drive it to full power, are you talking at the normal input of the amplifier or at the base of Q4. T3 is a step down transformer most likely designed to match the output Z of Q5 to the input of Q4. Diz is far more capable of answering your question than I. But, I am curious where you are getting 1 watt from and why you no longer want to use D2?
Tom, ak2b
=====================================================================================================
On 11/30/2009 21:03, wa8qfe posted:
Tom,
I'm wanting to use the amp for a Sierra, and don't need the input amp or the on board switching.
I'm just playing.....
Lee
=====================================================================================================
On 01/30/2010 18:45, ak2b posted:
The HYCAS board works perfectly well, itís just a little too big. I wanted something a little smaller in keeping with the Erector RX so I copied the K2 AGC stone for stone. Elecraft uses an NE602 to mix their 4.9 MHz IF with a 5.068 MHz crystal to 150 KHz, amplify it with an audio op-amp, rectify it and use it on the AGC pin of the MC1350. It is an interesting way to do agc. I swapped the 5.068 MHz crystal with a 4.9 MHz one. The board works fine and pretty close to the original. Iíve always like the agc in the K2 in that it is a nice gentle curve rather than reaching a threshold and keeping everything the same level. Jack Smith did an excellent analysis of the K2 agc.
The only thing that doesnít seem to work is the IF gain control. It doesnít make much of a difference in gain regardless of where it is set (unlike like the K2). I donít know how to fix this yet.
[img]http://tomnyc.no-ip.org/images/k2agc.jpg[/img]

Tom, ak2b
=====================================================================================================
On 01/30/2010 21:45, W4GNS posted:
I see you're a fan of those little blank PCB boards that Diz sales, I made an order a few weeks ago with Diz and fully meant to order some, but just plum forgot =( I think they look "cute"


[ak2b wrote:] "The HYCAS board works perfectly well, itís just a little too big. I wanted something a little smaller in keeping with the Erector RX so I copied the K2 AGC stone for stone.
The only thing that doesnít seem to work is the IF gain control. It doesnít make much of a difference in gain regardless of where it is set (unlike like the K2). I donít know how to fix this yet.


Tom, ak2b
"


=====================================================================================================
On 01/31/2010 11:37, ak2b posted:
Hi Gary,

Yes, I like the generic boards more and more. They actually are nicely spaced for size 802 smd's. You can buy smd's by the pound on the internet for very cheap. Here is another board I built up using a TriQuent AG302-86. They are $1.95 at Mouser. It is a handy dandy 16db gain block with a 50 ohm input/output impedance. It also comes in a slightly higher gain but the number escapes me at the moment. Pete, N6QW introduced me to these gain blocks. He uses two of them for a bi-directional amplifier that he has designed.

[img]http://tomnyc.no-ip.org/images/gainblocktop.jpg[/img]

[img]http://tomnyc.no-ip.org/images/gainblockbot.jpg[/img]
Tom, ak2b
=====================================================================================================
On 07/24/2010 14:25, ak2b posted:
I built the DDS Butterfly by Steve weber and put it up on YouTube

[img]http://tomnyc.no-ip.org/images/butterflydds.jpg[/img]

Tom, ak2b
=====================================================================================================