>I think the characteristics of so-called WD-1 surplus phone line varies.
> FWIW, the two short samples of WD-1 that I have here are as follows:
>
> 115 ohms impedance, calculated from the following: .033 diameter
> (averaged), .0685 spacing. The dielectric constant of the insulation
> (polyethylene) is 2.2.
By sweeping it with a carbon 250 ohm pot on one end, and a SWR meter on the
other, we can find a resistance value that results in minimal SWR change.
Then, by measuring pot resistance with a ohmmeter, we know one thing about
it.
An impedance error of 20 ohms on a 100 ohm line is as meaningful as an 80
ohm error on 400 ohm line.
By measuring attenuation of a reasonable length on several HF frequencies,
we could know loss. That would take minimal work and equipment, but a good
method.
The problem probably is there are so many types it might change between
types. I just wonder why no one has ever measured anything.
_______________________________________________
UR RST IS ... ... ..9 QSB QSB - hw? BK
|