KitsAndParts.Com Forum

AJ4TX · 2010-10-09 12:26:46

Hello there, reading the posts, you guys are a hoot! Been on the air since '73 and never used a balun... newbie on using toroids - been hiding under a rock, I guess.

I just wound a 4:1 balun using a T200-2 core. Use is for 3-30 Mhz. Going into an OCF dipole. First try at both balun and OCF antenna. May try 6:1 next.

I keep seeing references to FT-140-61 (or FT-140-43) in articles . Looking at the specs, wonder if a -43 would be better for this range?

Why the references to different cores? The T200-2 and FT0140-43/61 seem very different.

If I had a good list of cores and applications I would buy a nice variety.

Any words of wisdom? This is for a Guenella type current balun, not a transmitter output transformer.

Thanks,
Bill

W8DIZ · 2010-10-09 16:47:59

Need more info Bill...how much transmit power?
My favorite broadband xfmr uses an FT240-61 for high power or FT114-61 for QRP
type -43 material is a bit lossy and may heat up a bit
Type -2 material needs more turns than -61 and -43
73, Diz, W8DIZ

AJ4TX · 2010-10-09 23:49:00

Hi Diz, Thanks.

100W - 120W Max. So figure 50W typical, to 100 W. That's about all any of my rigs will do. I put 10 turns bifilar, parallel, on each hemi-circle of the T200-2. Still have to build the wire and figure out where it is going to live.

Wondering about the variety of methods called for - why one author will suggest say, a T200-2, and another the Ferrite xxx-61 or 43, all for an HF balun. Balun kit from thewireman.com is the 200-1 or 200-2 depending on if 160M or not. I bought some if each balun from him, before I found your store!

Details:
80M and up, no 160M on this antenna. Maybe on another one later. 10/15M might have their own antennae, but if it will load OK on 10, then I'll probably use it on 10. No 6M rig at the present. I loved 6M in the mid-70's. It was a blast!

Testing/characterization: I have a noise bridge... If I terminated the balun balanced side in 200 ohms and checked it out with the Rx and 50 ohms, should it read 50 ohm resistance and low X, or can you "check" a balun without a network analyzer? Or 200 ohms... hmm.

Bill

TAJones · 2011-03-30 18:18:44

Ok, here goes, first question. I am new to Radios and Electronics of any kind and wanting to learn and understand both. Can anybody suggest a good site or book for baluns, not to high tech, so I can understand them and build a few. I want to build a few antennas plus I need the therapy for my left hand as I lost my fine motor skills from strokes in 2007 and I am all thumbs now as right thumb was mashed completly off in the 90s and has no joints, just a stiff thumb, that I have learned to use. Thanks in advance for any help.

W8DIZ · 2011-03-30 20:49:33

Hi Tom,

I can not recommend any literature other that the ARRL Manual for Baluns but...there is nothing magic about baluns.
It is nothing more than a transformer that has one side connected to a balanced circuit and the other side connected to an unbalanced circuit.
Typical application is a connection from an unbalanced 50 ohm output of a transmitter to a balanced 300 ohm transmission line to a balanced antenna.

Let me repeat my first statement: It is nothing more than a transformer, usually for RF applications.

73, Diz, W8DIZ

TAJones · 2011-03-31 15:14:48

Thanks.. That is what I kind of thought. To me anything Electronic related is magic, mainly because of very little knowledge on the subject.

Last edited by TAJones (2011-03-31 15:47:26)

KitsAndParts.Com Forum

#1 2010-10-09 12:26:46

Baluns and cores

#2 2010-10-09 16:47:59

Re: Baluns and cores

#3 2010-10-09 23:49:00

Re: Baluns and cores

#4 2011-03-30 18:18:44

Re: Baluns and cores

#5 2011-03-30 20:49:33

Re: Baluns and cores

#6 2011-03-31 15:14:48

Re: Baluns and cores

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