The "high resistance wire" is nichrome. As I recall its attenuation is around 20 dB/100ft at 2m. I built an attenuator using it about 35 years ago. It handled the maximum power rating of the coax as long as the first 10 ft from the input was well spread out to prevent build up of heat.
There is a more modern version of this cable with the designation of RG-221 or RG-222 (sorry I cannot find my Times cable handbook to verify the number). It's attenuation is approximately the same. Burt VE2BMQ Doug wrote: > At 09:26 PM 24/03/2010, you wrote: >> Doug, >> >> From what I have found, RG-21A/U cable is 53 ohm impedance, 0.339" outer >> diameter, double silver-plated copper braid shields, and a solid center >> conductor of "high resistance wire." The dielectric is solid polyethylene, >> and the jacket is black PVC. If you have a sample of this wire, please >> reveal what is printed lengthwise on the jacket. >> >> 73, Eric Lemmon WB6FLY > ---- > Hi Eric. Well it has Plastoid Corportation RG-21/AU on the black jacket. > It is stiff coax. You describe it very well. I sort of remember using > something like this to reduce the power of an old Prog line unit... Here > in Canada they didn't allow us to turn the power down, you had to use > an attenuator. > > Thanks Eric > > Doug > > > > > ------------------------------------ > > > > Yahoo! Groups Links > > > >
