Distorted audio caused by RF feedback on early Elecraft K3s

[sm2o]

Thor TF4M who has a very early K3, had problem with distorted audio caused by RF feedback when he was installing his remote station. After lot of troubleshooting he found the Application Note from Elecraft.

http://www.elecraft.com/K3/mods/K3_Application_Note_Front_Panel_Microphone_Grounding.pdf

This was probably the solution, but instead of making this recommended change, hi made a new cable and connected the RRC to the K3 back mic input instead, and all problem was gone.

73 de mike

[sg3p]

I have problems with distortion in SSB. Seams to be related to the input gain in some way, and not due to RF feed back (same problem is geard even with QRP). If I only activate the PTT without talking, a noise can be heard. It gets worse if activate the compressor (naturally)... If increasing the codec input gain on the control side, the problem is less.

Maybe I have to test to connect the MIC on the back of the K3 instead.

Any reports of settings of input gain/micgain etc, with K3/RRC/Heil HC6/HC5?

73 de Gunnar SM3SGP

[sm2o]

Remember to remove the jumper which power the microphone. Heil microphones can not handle it. Otherwise default settings work well for the configuration.

73 de mike