Thank you Jim. I have read your white paper on RFI and grounding and your deliberations on the pin-1 problem. I guess I will have to read it again :-) It was about 1.5 years ago.
Ok, I will start piecing together a new set of interconnecting braid cables, as Don recommended, tonight. Joe, I feel as though I usurped your original thread. Hopefully it helped you as much as it helped me. regards, Brian VE3IBW On Fri, Jun 24, 2016 at 11:37 AM, Jim Brown <j...@audiosystemsgroup.com> wrote: > On Thu,6/23/2016 7:16 PM, Brian Waterworth wrote: > >> For some context on why I went to a common point. I read, what I thought >> was an excellent article, about ground loops from the Flexradio site a >> couple of years ago. Here is the link: >> http://kc.flex-radio.com/knowledgebasearticle50426.aspx >> >> I thought that daisy chaining would introduce ground loops and hence the >> reason I went to a common point. >> > Look at your equipment -- there is already a "daisy-chained" loop between > equipment in the form of those audio cables and coax. The problem, as Don > notes, is that they often don't go to the chassis, but rather to the > circuit board, which couples hum, buzz, and RFI into and out of equipment. > This is "The Pin One Problem," first identified by pro audio engineer Neil > Muncy (W3WJE, SK) in 1994. Virtually all ham gear, including Flex and > Elecraft, has Pin One Problems at audio and control connectors. > > However, I don't think you are advising this. >> > > Brian, > > Study my slides that Don referenced. The concept of a "ground loop" as a > cause of hum, buzz, and RFI is false, and causes people to do the WRONG > things to solve such problems. The slides show the TRUE cause, which is > leakage current from the AC power system. > > The ONLY way in which a "loop" is problematic is that it provides a path > for magnetic coupling between victim equipment and a strong magnetic field > produced by a noise source. Two common sources are 1) the stray fields > produced by big power transformers, and 2) a wiring error in home power > wiring called a "double-bonded neutral," where the neutral is bonded to the > green wire somewhere other than the point where power enters the building. > In both cases, the interference is heard as HUM (pure 60 Hz) rather than > BUZZ (harmonics of 60 Hz). > > 73, Jim K9YC > > > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:Elecraft@mailman.qth.net > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > Message delivered to brian.waterwo...@gmail.com > ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
