At 4:59 AM +0000 1/7/09, [email protected] wrote: > >Message: 6 >Date: Tue, 06 Jan 2009 21:54:41 -0600 >From: Brian Kirby <[email protected]> >Subject: Re: [time-nuts] Standards sought for immunity of shielded > cable links to power-frequency ground loops >To: Discussion of precise time and frequency measurement > <[email protected]> >Message-ID: <[email protected]> >Content-Type: text/plain; charset=ISO-8859-1; format=flowed > >During my experiences involving audio/phone, video and data >transmission, we were taught to ground the shield at one end only so we >would not cause a ground loop.
Yes, it's impossible to do this in a system of any size. In my experience, the RF cables connect the arms of the star-grounding system, causing loops. So, the receivers had to be immune. The problem is to quantify and specify the required degree of immunity. >I ran into problems everywhere I went with this and as much as folks >disdain transformers, they are your friend in this type of problem. DC blocks (usually a series capacitor) also work at RF. But we would have a lot of them. And we would still need some kind of spec to require, to know when we are done. >Don White Consultants/Interference Control Technology published a whole >series on EMI, Grounding, and EMC for the military. They are located in >Gainesville, VA. But do they publish formal and official requirements documents? That's what I need, versus training. Thanks, Joe _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
