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Random Wire Antenna

Darryl J Kelly
 

I have a 70' end fed wire, 10' at feed end up to a tree at 25', last
20' sloping down, 9:1 unun, 50' of coax on ground, 26' counterpoise
sloping down to and on ground. High SWR 6.7 at 6 meters, most much
lower, high impedance 110, also most much lower. Tuneable on 80
through 6 meters with LDG AT-200 Pro II tuner. I have very good SWR
measurements with different random lengths from 40' to 115'. Just my
experience.
Darryl, KK5IB

Ronald Morrison
 

Just because an antenna can be matched doesn't mean that it is a good radiator.  For one thing, the radiation pattern gets very complex at higher freq.  Height above ground has a major impact on the vertical angle of radiation, etc.  Also, you have high loss in the coax due to the high SWR on it.  A single counterpoise will have the same problem with a reactive impedance as the "random wire" has, so it is best to have at least one 1/4 wave radial for each band. In addition, radials are lossy on the ground.  Even one foot above ground is more efficient.

Ron, K5DUZ

On Sunday, June 14, 2020, 01:35:40 PM CDT, Darryl J Kelly <kk5ib01@...> wrote:


I have a 70' end fed wire, 10' at feed end up to a tree at 25', last
20' sloping down, 9:1 unun, 50' of coax on ground, 26' counterpoise
sloping down to and on ground. High SWR 6.7 at 6 meters, most much
lower, high impedance 110, also most much lower. Tuneable on 80
through 6 meters with LDG AT-200 Pro II tuner. I have very good SWR
measurements with different random lengths from 40' to 115'. Just my
experience.
Darryl, KK5IB