Yeah, it doesn't make much sense. I was thinking about RF in the shack - RF sometimes
does strange things. I put the amp on the bench just to look at it and measure the quiescent, which is 228 mA. The amp is called "XDT-PA70" and it has a pair of
IRF530N transistors.
I just looked up the IRF530N - it doesn't look like a super linear device. The
constant-current part of the curves is short.
When I have some more time, I might just stick an oscilloscope on it.
I did use a step attenuator - after the initial 30dB Narda. As I flipped
the switches, the peaks went up & down in a sensible manner. And the harmonic
& fundamental went up & down the same amount.
I also tried sticking using the tinySA with its antenna. My vertical is about a hundred feet up the hill from the shack. Same difference.
- Jerry
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