If you have a limited number of radials, as in 2,
you will definitely have favored directions.
In fact, even with 4 or more, you have to consider
that the mean vertical angle of the lowest lobe will
vary....being lower where the radials are present, and
higher in between, as Dale observes, below:
-0-
When I was a kid living in Whittier, CA, I had a roof-mounted 14avq with the
requisite pair of radials cut for each band. The radials were strung out
the length of our house roof -- North-South. I'm sure the years have
obscured/warped my perception of what I may have experienced, but it seems
like I worked a truckload more stations in the pacific NW/VE7/KL7/JA/UA than
to the east and west. So, are there directional effects by the placement of
a pair of radials? Or did I just imagine it?
73,
dale, kg5u
-0-
For the record, I still like the idea of the "halfwave" vertical...as in the
Cushcraft R7k or R8 design, where it can go on top of a tower, without the
spiderweb of radials. Neat, clean, decent pattern, reasonable efficiency.
Is it the ultimate in performance? Not compared to a single band vertical.
Is it pretty close? On 40 and higher, yes. On lower bands, a properly
installed
quarter wave vertical with in-ground radial system is preferred. But if you
can't
DO that...and have big trees....an elevated GP will work amazingly well,
over most
soil.
N2EA
jimjarvis@ieee.org
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Stations", and lot's more. Call Toll Free, 1-800-333-9041 with any questions
and ask for Sherman, W2FLA.
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