[Elecraft] Re: I^2*R Losses and Coax Impedance (Was Random Wire)

Sat Jan 11 00:54:00 2003

I have just purchased Kraus Antennas and Kraus Electromagnetics and have not
got far with them as yet, however, I question Stuart's assertion that with
respect to coax feeders, "... the higher the impedance the lower the I
squared R losses of a feeder."

Surely the I^2*R losses have to do with the resistive losses of  the copper
conductor and the parallel conductance of the dielectric.  At low
frequencies these are practically negligible unless you have a very long
cable and are running high powers.  A coax cable would still have a
characteristic impedance even if the conductors had zero resistance.

Somebody with more knowledge will no doubt correct me for which I would be
grateful.

73
Kevin
VK3DAP

----- Original Message -----
From: "Stuart Rohre" <[email protected]>
To: "Peter Halpin" <[email protected]>; <[email protected]>; "Steve
Lawrence" <[email protected]>
Sent: Saturday, January 11, 2003 1:59 PM
Subject: Re: [Elecraft] Random Wire???

> Ahhh, the global marketplace makes it mark on coax.  Too bad,
> Video Coax in USA is still 75; and of course the higher the impedance the
> lower the I squared R losses of a feeder.  At the time the referenced G
> antenna book was written 75 seemed to be much quoted in it.  Good book
none
> the less, for not having the most current coax impedance of UK.
> 72,
> Stuart K5KVH
>
>
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