There has been a recent thread regards putting a ground screen at the
base of the tower and extending (purportedly) for a modest distance
from the tower throughout a housing lot. There has been several statements
regarding the effect on the take-off angle that the wire screen might or
might not have. I would only like to add my personal experience in this
regard without comment on the effect of the below-the-antenna ground system
vs. the effect of distant reflection ground some thousands of feet or miles
While living in Tucson in 1966 and 1967, I constructed a 3 el 20, 4 el 15 &
10 meter quad at 60 feet (Feb 1967 issue of QST). The most pronounced
propagation phenomena I encountered was that when the soil was dry, I was
able to hear and to work Europeans with some success...... but when it rained,
I couldn't hear jack squat for 2-3 days afterward on any long haul DX. I
attributed this (albeit it may be in error - if it is, please explain how)
to the "virtual" rf ground being considerably below the literal ground when
the soil was dry and therefore the take-off angle was considerably lower on
transmit. The received rf angle appeared to have tracked with that as well.
When it rained, the conductive nature of the soil was enhanced and made the
antenna considerably closer to the ground and hence the take-off angle was
sufficiently higher enough to rule out long haul dx.
Don't know if it was far field reflection or the field close at hand that
might have caused that effect. There can be no doubt, tho, as to whether
it existed or not. I observed it many times. Any comments?
Remember! Unconstructive flames give me gas!
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