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#1 2012-01-20 07:38:03
- w5rkl
- New member
- Registered: 2012-01-20
- Posts: 1
Universal Wide Band Amplifier
What is the input impedance of the Universal Wide Band amplifier? The only impedance information I can find mentions the "output" impedance, either 50 or 200 ohms, determined when winding the toroid during assembly.
73s
Mike
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#2 2012-01-21 05:27:21
- W8DIZ
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- Registered: 2008-08-12
- Posts: 317
Re: Universal Wide Band Amplifier
nominally 50 ohms input Z
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#3 2012-01-21 11:15:43
- ak2b
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- From: New York City
- Registered: 2008-08-12
- Posts: 338
Re: Universal Wide Band Amplifier
Here is an input scan of the Universal WideBand Amplifier. Not too shabby 
.
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#4 2012-03-11 01:04:27
- KC7NOA
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- Registered: 2010-10-08
- Posts: 35
Re: Universal Wide Band Amplifier
What is the max in/out?
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#5 2012-03-11 11:45:04
- ak2b
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- From: New York City
- Registered: 2008-08-12
- Posts: 338
Re: Universal Wide Band Amplifier
The input is -16.5 dBm (94mV p-p)
The output is 0dBm plus 6db for the pad or + 6dBm (1.28V p-p into 50 ohms).
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#6 2012-03-11 12:05:38
- ak2b
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- From: New York City
- Registered: 2008-08-12
- Posts: 338
Re: Universal Wide Band Amplifier
I did this today with the same amp on 18.076MHz
The top picture shows harmonic output with a pretty high input of -7dBm(280mV p-p)*
Looking at the ouput on a scope terminated in 50 ohms, the sine wave starts to look pretty bad when increased much above -7dbm.
All-in-all this is a time tested design and you should expect very good results when driving it with about 150mv p-p (give or take).
Add 6 db to the output power because of the pad I used with this amp.
The picture below it is at -17dBm (89mV p-p)*
*all measurements are into or out of 50 ohm impedances
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#7 2012-03-11 14:44:03
- KC7NOA
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- Registered: 2010-10-08
- Posts: 35
Re: Universal Wide Band Amplifier
So ... about 50uW of drive for less than 10mW out .... ok, my sdr puts out 50mWthe so this wont help ....
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#8 2012-03-12 07:26:39
- W8DIZ
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- Registered: 2008-08-12
- Posts: 317
Re: Universal Wide Band Amplifier
The RF Amp is designed to be a low level Amp (aka preamp).
It is NOT a RF driver amp.
That being said, it could easily be modified for higher power and/or class-c operation to the 1 watt output level.
-Diz, W8DIZ
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#9 2012-03-12 09:43:47
- KC7NOA
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- Registered: 2010-10-08
- Posts: 35
Re: Universal Wide Band Amplifier
Gota be linear ....
Is there a documented mod? Schematic? Deferent transistor perhaps ... I have several 2n3866 that are/were for my Atlas350/210/215X ....
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