[Skimmertalk] ground loop reduction?

David Gilbert xdavid at cis-broadband.com
Wed Nov 21 21:11:07 EST 2012


Presumably you have an RS-232 connection to the KX3, right?  That can be 
problematic for this sort of thing.   Just for grins, try bonding the 
chassis of your computer to the chassis of the KX3 with the shortest 
copper strap or heavy braid you can manage.  I mean really short ... as 
in six or eight inches of something 1/2 inch wide.  If it makes a 
difference you'll know what to work on.

73,
Dave   AB7E



On 11/21/2012 6:36 PM, Mark n2qt wrote:
> I'm using cw skimmer with a non offset I/Q feed (from a Elecraft KX3).
> I have excessive ground loop noise regardless of the sound card I use
> (EMU-0202 USB or Quartet).  Using transformers for ground isolation
> doesn't help, in fact the ground noise is there regardless of connection
> to the sound cards.   The noise sidebands go out about +/- 300 hz from
> 0.
> Normally the ground noise is offset from the signal and hasn't bothered
> me when using an LP-PAN (6khz offset) or Softrock (23Khz offset) but 
> with the kx3 it's a real annoyance since it's so close to the desired.
> Looking for positive experiences on fixing this....
>
> Mark n2qt
>
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