[TowerTalk] 75 to 50 ohm connection question

Jim Brown jim at audiosystemsgroup.com
Fri Mar 16 21:52:15 EST 2007


On Fri, 16 Mar 2007 12:55:52 -0500, Bill Gillenwater wrote:

>I have a run of RG 6 quad shield

The mismatch between 75 ohm cable and a 50 ohm load is no big deal, 
except to the extent that the somewhat higher SWR might cause your 
transmitter to be a bit unhappy and pull back the power. This is 
easily solved with an antenna tuner. The loss in the feedline due to 
the mismatch is negigible, and the cable you describe will easily 
handle FAR more than 100 watts.

>From a practical point of view, the most important thing you can do 
is provide the best practical "ground plane" (radials) for the 
vertical you describe. Don't worry about textbook, just remember 
that more is better. The ARRL Antenna Book has an EXCELLENT 
discussion of this.

Jim Brown K9YC





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