Login  Register

Odd audio feedback problem

Posted by George Thornton on Sep 07, 2010; 5:01pm
URL: http://elecraft.85.s1.nabble.com/Odd-audio-feedback-problem-tp5507365.html

I seem to have an elusive audio feedback problem.  It is not always
there but when it's there it's bad enough to render me unintelligible on
voice Tx.  I am posting this because maybe someone has seen this before
and can enlighten me.

 

I am operating with the LP-Pan and am using Power SDR for software.  I
am using the E-Mu (I think 0202) sound card.  My computer is an older
Lenovo T60P laptop loaded with Windows 7.  

 

For PSK I bought a second sound card, some kind of a hockey puck style
USB card that was recommended from this list.    I got the second card
because I was not able to see how the LP-Pan allows for transmit of PSK
from the computer.  I use HRD and DM780 for PSK.

 

The feedback is intermittent.  Sometimes it is there, sometimes not.  I
have tried silencing the K3 speakers, reducing MON to 0 and using
headphones, still it happens.

 

Turning off the computer eliminates the feedback.  Sometimes unplugging
one of the sound cards eliminates the feedback.   I also tried silencing
the computer microphone, presuming that the microphone was picking up
audio from the spoken Tx and feeding it back somehow through one of the
sound cards.  

 

Anyone ever encounter something like this before?  I suspect it is
something obvious that needs to be set in the computer.  

 

 

______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html