What affect is there of vertical *resistance* variations are the common
4-square boxes?
N6LF’s QEX article shows quantitatively the performance hit associated with
using non-resonant elevated radials. Which is interesting because non-resonant
radial lengths reduce the sensitivity of individual elevated radial variations
from ideal. However, by altering the relative lengths of the vertical/radial,
the feedpoint R moves around.
I ran a simple test case pair in EZNEC. First was the resonant radial case
(length is the same as the vertical radiator). Second was shortened radials
(about 10%) with the vertical lengthened to restore the same X=0 frequency.
The feedpoint R moves from 32 ohms in the symmetric case to about 40 ohms in
the short-radials case.
The R has got to translate into a drive impedance shift - but I am wondering
what the expected impact to the array should be?
73/jeff/ac0c
www.ac0c.com
alpha-charlie-zero-charlie
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Topband Reflector
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