Hi, Please indicate a source of twisted pair wire suitable for speaker feeds. #16 or #14 is fine for me. I am still having trouble keeping my 15m signals out of my family room system. Currently that room's speaker wire is of the parallel kind.
AB2TC - Knut Jim Brown-10 wrote >> Your position should be to offer to assist a qualified technician in >> >isolating and correcting any deficiencies by providing periods of >> >operating to test the results of any repairs. > > I'd say it depends entirely on the attitude of the RFI victiim, and the > ham's relationship with that party. The vast majority of RFI complaints > today are the result of Pin One Problems in the victim equipment. These > are a manufacturing defect that is the result of poor design, and any > wiring connected to the equipment will act as a receiving antenna for > our signals, where they will be rectified and amplified. > > In today's world, "qualified technician" for consumer electronics is an > oxymoron. > > Several years ago, I helped ND2T diagnose and cure strong RFI to his > next door neighbor's "exotic high futility" system, in a living room > only 20 ft from Tom's antennas, which were driven by a big ACOM legal > limit amp. Tom introduced me as an audio expert and RFI expert (which I > am) then returned to his shack and transmitted on all the bands. I stuck > chokes on cables until the RFI went away, and by the time Tom arrived > after our work was done, had the guy ready to open his wallet to buy > them at my cost. Tom, however, insisted on paying for the cores > himself. Problem solved. > > It is NEVER a good idea to modify the equipment, but it IS good to > disable the antennas (that wiring) by adding ferrite chokes tuned to the > transmitter frequency(ies). Tuning is accomplished simply by using the > "right" ferrite mix and adjusting the number of turns through the core. > > Speaker cables are a very common antenna. Another excellent move is to > replace parallel wire loudspeaker cables (zip cord, no matter how > exotic) by twisted pair. #12 copper makes excellent speaker cable > (there's a classic AES Paper by Prof. R. A Greiner, Dept of EE at U Wis > about this), and twisting strongly rejects RF coupling. I have solved > MANY cases of RFI by doing this. > > RFI causes and solutions are covered in considerable detail in > > http://audiosystemsgroup.com/RFI-Ham.pdf > > 73, Jim K9YC > <snip> -- View this message in context: http://elecraft.365791.n2.nabble.com/OT-RFI-Issue-tp7571483p7571594.html Sent from the Elecraft mailing list archive at Nabble.com. ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
