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[antennaware] Feeding cable lenght

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Subject: [antennaware] Feeding cable lenght
From: (K4SB)
Date: Wed, 04 Aug 1999 00:46:34 +0100
Serge wrote 

>     But SWR in any point of this line will be 600/50=12:1.
> And attenuation in line will be bigger then when SWR 1:1.
> SWR never depends of line length.
> (It will be only better on trx side because of losses in line).
> 73 de Serge UT2IO.

No, that is not correct. Remember that SWR is Voltage Standing
Wave Ratio, and on a 1/2 electrical line, both the forward and
reflected voltages are 180 degrees out of phase. It matters not
that the SWR might be 12:1 ( or any other number, and that well
may be true at other points on the line ), but ONLY the condition
which exists at the input and output ends of the coax. The line
will repeat the load impedence at the other end.

You are correct that the attenuation of the coax will slightly
diminish the true reading because coax ( or any other ) is not a
perfect lossless line. However, good quality coax will only
introduce less than 1 db of loss through 28 mHz, depending on the
frequency. CATV cable will have even less that loss.


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