[RFI] RE: Accessory port RFI

Chris Tobias Chris Tobias <kd3oa@ptd.net>
Fri, 27 Mar 1998 12:27:00 +0000

>Was pleased to see an "Accessory" port on the back on my Icom 737.  It works
>well with my TNC for packet, rtty, etc.  Unfortunately,  the microphone audio
>is distorted (quite badly, I'm told) when a cable remains connected to this
>port.   I've tried the Radio Shack chokes which separate in to two C-shaped
>sections.   No luck.  Audio is still so bad I just unplug the cable.   Any
>Kelly Boswell

I had a similar "microphone audio distortion" when my PK-232 was connected to 
the accessory jack of my ICOM IC-735.  I installed a toggle switch on the
cable, and switched the TX audio and PTT lines.  By all reports,
disconnecting the TX
audio has eliminated the microphone distortion.  I suspect a problem with
the output of the microphone preamp, but I don't know.  I won't argue with

I'll just suggest that your problem *might not* be RFI-related.

73, Chris Tobias

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