Topband: elevated radials

Tom Rauch w8ji at contesting.com
Sat Aug 5 21:08:14 EDT 2006


Tom, heretofore, a buried radial system under 1/4wL vertical 
was evaluated based on how close the actual impedance was to 
the 36 ohm R of the classic monopole.  If I understand your 
last comment correctly, you indicate that the R value fails 
to predict field strength?  Can you describe what you mean? 
Or better yet, what you are observing?  Possibly more 
importantly, how you measured it?>>

Any time I've measured base impedance it has been with a 
calibrated piece of equipment right at the antenna.

I've seen cases in the past where base impedance hung around 
the same value while FS increased with more radials, and 
other cases where a ground that provided a low impedance 
wasn't as good as one that provided higher impedance. Based 
on that,  base impedance even on a simple 1/4 wl monopole 
isn't always a reliable indicator of efficiency.

If you want to know field strength change it is best to 
measure field strength, and not something else.

73 Tom 




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