Joe,
Do you hear that hum when you operate into a dummy load? If not, then
check the common mode choke on the antenna, you are likely getting
RF-In-the-Shack from the antenna - the fact that it diminishes when you
put your hand on the K3 amplifies that this may be the problem. Forget
about grounding the radio for this problem, solve it at the antenna
feedpoint with a good common mode choke on the feedline.
Other possibilities are power supply ripple (run it on battery to check)
or an open microphone ground lead (try other microphones).
Make sure the rear panel jacks are fully plugged (give them an extra push).
73,
Don W3FPR
On 12/2/2018 4:17 PM, Joe Rogers wrote:
I normally operate CW but the other day and have not been SSB for a few weeks
to a month. Yesterday, I was getting ready to operate SSB and I noted a hum
through the monitor when I key the transmitter. By way of background, K3 is
2012 vintage and I assembled the kit. No problems with until this one. I have
found several similar threads mentioning a hum on SSB transmit but of the
mentioned solutions worked to solve my problem.
I have Heil Pro set IC and Heil Gold Elite. The problem seems much more
pronounced with Proset IC.
Whether it is connected to front panel (FP.H or RP.H Bias on) makes no
difference. If I used PTT or VOX it is there. Set Mic Gain at anything above
zero it starts. With higher mic gain and higher compression it is worse. I
have made some PSK contacts using the LIN IN input and seems to work OK.
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