I am about to configure antennas for my 3rd Topband season here in WV. The
terrain is very irregular. My house sits atop a conical shaped hill, with
sides which slope off steeply in all directions. All of my transmit antennas
are on top of the hill, overlooking the steep slopes including the 160 inverted
L's, which are configured with the vertical portion of the radiator right at or
just over the cusp of the hill, with the ground falling away steeply in the
desired direction. Last year, I used four of these L's, each positioned to
cover a direction favored by sloping ground. Switching between them exhibited
noticable directivity on rx and tx, so I am convinced we are on the right track
with the tx antennas.
I am not sure what to do about the rx antennas. They can't be placed on the
high ground, due to space and driveway constraints. The first season, we tried
several short beverages and last year we added four dual flag antennas. There
are not many options for the beverages. To cover desired directions with my
property layout and the terrain, these must be placed on the sides of the hill,
some running upslope, some downslope and some sideslope. They seem to work OK,
some directions better than others. Generally, I found that an upslope
beverage is the poorest performer.
My real question regards the best way to orient the flags in relation to the
sloping ground. I have some choices. In some cases, we can go sideslope, so
the antenna is both level and parallel to the ground surface in the primary
target direction. In other cases, I am faced with the choice of either making
the antenna array level, which puts one end significantly higher above ground
surface than the other or placing the antenna array parallel with the earth
surface, which makes the whole array tilt downhill in relation to the horizon.
The flags I am using are 21' high by 30' long, thus making the double flag
array about 63' long.
My intuition with these antennas says to avoid putting one upslope entirely,
and when possible to make it sideslope. However there are some directions
where we must go downslope, and my instinct is to follow the earth surface and
have the array tilt down in relation to the horizon. Anyone got any experience
with this, or any thoughts about it making any difference in the real world?
73 Chas N8RR
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UR RST IS ... ... ..9 QSB QSB - hw? BK
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