[WriteLog] SSB Messages Bleeding into Headphones

[Dennis Mowers <k5ya@gvtc.com>]

I'm using a W5XD keyer for my headphone connection.  Radios are TS-850's.

My recorded messages from the soundcard are getting into the headphone 
path somehow.  The sound is very muffled, and hard to understand, but 
loud enough to cover up a weak signal caller.  It happens on the 
transmitting radio audio, or the same level on the 2nd radio audio when 
I'm in the latched headphone position. 

I have the normal MIC to rig connections, via the soundcard, using 
isolation transformers on the sound card output.

Looking at the Keyer schematic, the headphone audio is switched with 
relays, and there is no apparent  connection with the soundcard.  The 
headphone connections have been moved several feet away from the mic 
in/out wires, and that doesn't help.

The only other thing that is not quite normal is a very low level 60 Hz 
hum in the headphones when the rig is switched to transmit.  I have 
removed the PTT outputs from the Keyer to the radios, and used VOX, and 
still get the hum when the VOX triggers the radios. 

It's not RF, because I have the rig power and  carrier levels turned all 
the way down. 

If I go to the Keyer, unplug a headphone input and headphone output, and 
connect them with a short jumper, removing the Keyer grounds and 
internal relay from the picture, the problem  goes away.

Has anyone had a similar problem?  What should I try next?

73, Dennis - K5YA




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