Topband: Radial length

EP Swynar gswynar at
Thu Nov 30 16:07:51 EST 2006

On Thursday 30th November Peter wrote...

> Here's a question: If I bunch let's say 10 or 15 radials together to go
'round the back of the garage, then spread their ends out on the other side,
would that be effective or a waste of copper?

Hi Peter et al,

Back in December 1976's issue of QST magazine, a fellow named John O.
Stanley (K4ERO/HC1) wrote a very informative discourse on this very subject,
entitled, "Optimum Ground Systems For Vertical Antennas" (pp. 13-15). If
your collection of QSTs doesn't quite go back that far, look at the newest
edition of the ARR:'s Antenna Handbook for a table summary therein...

In a nutshell, actual radial *length* is optimized by actual radial
*number*, specifically:

-For 16 radials, 0.1-wavelengths long is optimal;
-For 24 radials, 0.125-wavelengths long is optimal;
-For 36 radials, 0.15-wavelengths long is optimal;
-For 60 radials, 0.2-wavelengths long is optimal;
-For 90 radials, 0.25-wavelengths long is optimal, and,
-For 120 radials, 0.4 wavelengths long is optimal.

The writer did some historical research to support these claims, & I think
his presentation is about as good a summary as any I've seen around--- 
certainly far superior to the generalized, blanket statement of, "...the
more radials, the merrier" that one hears on so many occasions.

Obviously the technical staff at ARRL agrees, too, as they've incorporated a
30 year old paper into a 2006 book...and that's certainly good enough for
me! Hi

~73~ Eddy VE3CUI - VE3XZ

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