[Amps] High SWR on 15 mtrs for SB220 - Follow-up

Vic Rosenthal vic at rakefet.com
Fri Mar 19 07:45:29 EST 2004


Bill Spickler wrote:

> One last thought was to try a different length of coax
> between the 940 and the amp.  I was using a 44.5" piece of RG8U.  I
> added another short coax of the same length (kept the original in
> series as a test to see if it was bad) and guess what..... SWR 1.3:1,
> no tuner.  I then tried another jumper, RG8X 60".... SWR 1.2:1.

Although changing the length of a transmission line will change the 
impedance seen by the source, it does not change the SWR on the line. 
It doesn't matter whether the load is an amplifier or an antenna.

Therefore, something else is going on.  Perhaps the 940's SWR indicator 
was misled by a large amount of RF flowing on the shield of the coax, RF 
picked up from the antenna?

-- 
73,
Vic, K2VCO
Fresno CA
http://www.qsl.net/k2vco



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