Thanks very much for the suggestions, Jim -- all sounds like good advice.
On 5/10/20 2:24 PM, Jim Brown wrote:
> 1) Is what you hear HUM (pure 60 Hz) or BUZZ (harmonics of 60 Hz)?
Without routing the KX3's audio out to a soundcard and looking at the
waveform(s) on a PC, I'm going to say it sounds to my ear like a pretty
pure hum, not a buzz.
> 2) Make sure that the adapters you got are actually doing what you
think they are ...
>
> 3) Make sure that bias is turned on ...
>
> 4) Make sure that Mic Gain and Comp are not turned up too high. ...
>
> 5) For TXEQ, set three lowest bands (50, 100, 200 Hz) for max cut,
set next
> band (400 Hz) for 6dB cut), set the top two bands for about 6dB
boost.
All those points were good.
> 6) Make sure that everything in your station that connects to AC
power, ... has their
> chassis bonded together AND powered from the same outlet, ...
In the initial test, which produced the hum, the power source for the
KX3 was a Pro Audio Engineering PAE-Kx33 low-RFI supply. This PSU was
plugged into the same outlet as a variety of other shack gear, some
powered on. The only other things connected to the KX3 were (a) an
antenna intended for field use, and (b) the CM500.
I noticed that when I touched the shield on the antenna coax's BNC
connector with my finger, the hum diminished substantially.
I then unplugged the PSU and replaced it with a car battery charged to
12.01v. Now the hum appeared to be completely gone.
So, if I were to keep using the KX3 within the shack, it sounds as
though a thorough grounding/bonding workup would probably fix the
problem. I'm in the process of working through
http://k9yc.com/GroundingAndAudio.pdf.
I was mostly curious why the CM500's mic produced the hum, but the
handheld mic that came with the KX3 didn't. The CM500 has a quite long
cable, and I wondered if that could be part of the problem.
Thanks again and 73,
Frank K6FOD
______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[email protected]
This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to [email protected]
