Re: Finished my Nouveau 75, hum on transmit audio!

Duane Brayton

Sorry, I got the other msg first.  In that case mic cord shielding & rf feedback are possibilities. Keying the transmitter without mic attached should resolve that question quickly. You should be able to easily determine the keying line at the mic cord Jack and apply a temporary ground while checking the rf waveform. Let us know how that goes.
Duane KE0IUV

On Nov 21, 2019, at 10:00 AM, "John P Lloyd via Groups.Io" < target=_blank>> wrote:
Hello Bob,
I have tried it on 3 power supplies, in fact. One on my workbench (a switcher) and the other two are 50 amp astron's that I use everyday in the shack.
I always troubleshoot into a dummy load with a watt meter in line.
Putting it on an antenna has the same result with the hum.
The voltage from the PS's is 13.8.

I'm going to look into it a bit more this weekend, and let  you know if I come up with anything, especially about the power output.

Thanks for  replying!

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