[geeks] T-3 Coax as Audio Cable

[Jochen Kunz]

On Fri, 5 Oct 2007 12:42:57 -0400 (EDT)
der Mouse <mouse at Rodents.Montreal.QC.CA> wrote:

> >> hams run 2kw through coax all the time.
> But, don't forget, hams use substantially higher frequencies.
And different impedances, i.e. 50 Ohm. Higher impedance => higer voltage
=> lower current. The higher the voltage and the lower the current the
more power can be carried by a wire.

> Does this matter?  I don't know, but it is at least plausible to me
> that it could.  I'm no transmission-line theorist.  I do, however,
> know that high frequency in wires travels more by skin effect than by
> the bulk movement of electrons that low frequencies use....
Yes, there is also the skin effect. And there is dielectric loss, that
will heat the dielectric of the cable. (The dielectric is the
"insulation" between the inner wire and the shild.)

At audio frequencies things are quite different. There is almost no skin
effect and no dielectic loss. The resistance of the copper is way more
important at these near DC frequencies. But coax cables like AIRCOM PLUS
or even RG213 have quite low DC resistance. So there is no problem
pushing a few amps through them.
--


tsch|_,
       Jochen

Homepage: http://www.unixag-kl.fh-kl.de/~jkunz/