There is a ground loop between the D44 mounting bracket and the PCI bus ground. Isolating the card from the chassis by insulating the L bracket is perfectly acceptable. We do it all the time for PCs in Telecom COs to minimize noise and to make the systems NEBS compliant.
-Tim ----- Integrated Technical Services -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Gerald Capodieci Sent: Sunday, February 11, 2007 5:34 PM To: flexradio@flex-radio.biz; Hans J. Smit; Edwin Marzan; WARD, AL; kd5nwa Subject: [Flexradio] 24. Transmit noise - Computer generated with D44(Gerald Capodieci) FOUND IT! The problem was possible due to the D44-card-to-computer-case connection. I used electrical tape to isolate the D44 card's L-bracket mount from the metal of the computer. The bottom tab and the sides of the L-bracket were taped to electrically insulate the card from the computer case. Now there's no raspy noise and about a 10db reduction in amplifier hiss. It is possible that for some reason, the D44's ground needs to be isolated from the computer case. Now, I've only just did this and it seems great, however if something blows up later, I'll update this posting. Thanks everybody for all the suggestions. Jerry -------------- next part -------------- An HTML attachment was scrubbed... URL: http://mail.flex-radio.biz/pipermail/flexradio_flex-radio.biz/attachment s/20070211/017f50ab/attachment.html _______________________________________________ FlexRadio mailing list FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archive Link: http://www.mail-archive.com/flexradio%40flex-radio.biz/ FlexRadio Homepage: http://www.flex-radio.com/ FlexRadio Knowledge Base: http://kb.flex-radio.com/ _______________________________________________ FlexRadio mailing list FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archive Link: http://www.mail-archive.com/flexradio%40flex-radio.biz/ FlexRadio Homepage: http://www.flex-radio.com/ FlexRadio Knowledge Base: http://kb.flex-radio.com/
