Hello Horst,

This is the soundcard:
http://shop.zeg-shop.de/shop/index.asp?id=120340&sid=2670421779  It
costs 8,99 Euro ;-)
It is nothing special but the advantage is that it is not installed in
my notebook. So it can be kept apart from the PC by a cable and there
are possibilities for additional decoupling.
But normally the noise of the RX and preamp should be higher so that the
noise of the soundcard becomes irrelevant. But it is a way to check if
an improvement can be achieved...

73, Stefan/DK7FC

Am 03.03.2010 10:32, schrieb Horst Stöcker:

 And what about a simple band pass filter to supress the 50Hz and it's 
harmonics? Necessary or dispensable?

 You can hear (!) the difference. I just took a 10mH coil from Reichelt to 
improve my soundcard-RX before one of the last SAQ activities.

 Despite of more or less excellent digital filtering of SpecLab it's a good 
idea. One should not keep the soundcard busy with unwanted signals.

 What I am not sure about is the use of an audio transformer. It might have 
some influence to the signal. As it just has to keep the soundcard from beeing 
blown it might be a good idea to take a cheap soundcard instead of the audio 
transformer - and maybe a second in spare.

 Stefan, what USB-soundcard you bought for 10 EUR ?

 Horst DO1KHS
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