[WriteLog] Sound card duplex operation?

[Clive Whelan]

Hi list

I'm not sure that the title really describes what I want to convey, please
excuse my inarticulation.

This is the problem. I am mainly - like 99%- a CW operator, but have been
known to run the occasional RTTY contest, even pick up a microphone!
Particularly noticeable has been that when running say RTTY, I get what I
would describe as feedback when transmitting canned message files -viz F
keys, despite having carefully muted all non used inputs/outputs. I had
assumed that this was a dysfunction of my soundcard, or even something in
the transceiver itself. However, quite recently I was testing an IC7400, and
also concurrently installed an external sound card ( Trust brand), but yet
the problem was exactly the same, thus eliminating both my prime suspects!
Armed with this evidence, I eventually discovered that if I muted line input
to the sound card ( the recording feed from the transceiver) then the output
from line out to the transceiver was now free of feedback. So far so good,
but this means that I cannot record audio snapshots in real time.

Now I know that others are not so afflicted, so I am really baffled as to
what the problem really is. Do the RTTY buffs have any ideas? Oh I should
have said that feedback occurs even with the line in slider at absolute
minimum, so it's not a level problem per se.

Tips appreciated.


73


Clive
GW3NJW