Topband: Measuring ground screen resistance

[rick@area.com]

There was some recent discussion about chicken wire ground screens
vs conventional radials.  What I would like to know is:  how do
you measure any proposed ground screen to determine its ground losses?
You can measure the driving point impedance of a vertical antenna
and subtract 36.5 ohms to get "ground resistance".  HOWEVER, it isn't
necessarily true that the impedance of your particular vertical is
36.5 ohms (that number is for a zero radius wire).  Should the vertical
be a physical 1/4 wave long, or shortened to resonance?  Should the
test vertical be a piece of thin magnet wire held up by a string?

Remember:  if you can't measure it, you can't optimize it, as the
saying goes. 

Rick Karlquist N6RK
rick@area.com



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