[SOC] Need help with a PSK-31 Problem

[bob baxter]

Rob,
Go to  WM2U's web site at
http://www.qsl.net/wm2u/psk31.html
Pick up a few bux worth of parts at RS and put together his interface.
It has isolation xformers on audio in and out lines and an opto-isolater
circuit for ptt.  I've been using it for abt 3 years and it works great.
The only mod I did was to add a pot in the audio out to more easily set
the sound card level when changing bands.  Or you can spend a hundred
bux for a rig-blaster.
Bob Baxter AA7EQ
Bisbee, Az.


> Was in QSO last night when I was informed that I was putting out audio
> harmonics every 1.5kHz.  The guy on the other end informed me that it
may be
> caused by an impedance mismatch.  I thought this may be likely as I'm
just
> running 50 ohm coax with the appropriate connectors on each end from
the
> sound card to the Kenwood.  No impedance matching transformer, etc.
>
> When I flip to the moni position on the Kenwood, I do hear a slight
bit of
> hum on occasion, but I've been told that it doesn't come through the
> transmitt.
>
> Anyone got any clues as to how I can solve this?
>
> Also, does anyone know of an ACTIVE psk-31 e-mail reflector that I can
get
> on?
>
> TIA