KLUDGE@AGCB1.LARC.NASA.GOV (08/13/90)
Just got in a nifty new Sun Sparcstation SLC, and discovered I didn't have enough RG-58 in my desk to reach the nearest cheapernet connection. So I went into [orchestral flourish] The Back Room in search of cable. I found lots of RG-59... miles of the stuff. And I also found a reel of something mysterious, that I thought at first was RG-58. It was marked "R. Gillian-- Low Noise 1-conductor cable." Mr. Gillian was working on a couple of instrumentation projects in the early seventies, including strain guages, accelerometers, and other microvolt-range low-hertz range sensors. And he wasn't around, so he probably didn't need this cable, marked "Amphenol No. 21-537." So, rather than let taxpayers' dollars go to waste, I made up some stereo interconnects. It's interesting stuff. The center conductor has a large number of very fine conductors, elliptical in cross-section, covered by a clear plastic dialectric slightly smaller than that used in RG-58. The center conductor strands seem to be silver-solder-plated. Over the insulator is a coat of powdered graphite under a tightly-woven mesh. And then the ouer jacket. It has a higher impedance than RG-58 (my pulse generator is broken so I don't know exactly what the value is), and much lower triboelectric noise. Triboelectric noise (or handling noise) is a problem with stage mikes and guitar cables, because of the amount of movement. It's not much a problem for stereo interconnects, and I can't hear any difference between this stuff and RG-58 really. But it's still good cable. You might look into this stuff for stage microphones or guitar cables (this is not to be taken as a statement by the author condoning use of stage microphones or electric guitars... one look at Mick Jagger's face easily demonstrates the ravages of these evils... but merely a recommendation to those who may use them), or look into the Belden low-tribo cables. The Belden cables have a special dielectric which generates less static charge when compressed, but tends to breakdown at RF frequencies. I don't know if this cable has a similar dielectric but I am interested in finding out. --scott