Tim Duffy K3LR <k3lr@k3lr.com> wrote:I am curious if there are directional
improvements to be gained with Beverage antennas with respect to height above
ground? What changes at 6 ft, 8 ft or 10 ft? How important is it to have the
height consistent over the entire length of the Beverage?
....
Over the 35 years or so I have been building and using Beverages, I've paid
attention to what works and what does not work. The following observations are
consistent and reproducible over many years and several different locations:
1) Lower is better (generally speaking)
2) Short Bev's (under 300 feet) are worthless if made 10 feet high.
3) Short Bev's (under 300 feet) out perform computer predictions if laid on the
ground or at least not more than 30 inches above it.
4) The closer to the dirt, the less interaction there is with surrounding
structures.
5) Longer Bev's (over 600 feet) are worthless if laid on the ground.
6) There is some evidence (but not conclusive) that very long Bev's work better
if higher, say 10 feet or a little more. If I have the opportunity, I would
like to look at this again.
7) Raising and lowering the wire height (for instance over a driveway) of
moderate to long length Bev's does not seem to adversely affect performance.
8) I have some results that indicate it is better to follow the terrain than to
suspend over low areas like dry washes and gulleys. I have not been able to
verify this observation in enough different locations to be certain it is
always true.
9) Every Bev I've installed with height above ground of between 24 and 36
inches and lengths between 200 feet and 1200 feet has met or exceeded
performance expectations. Wires installed at heights between 8 feet and 10 feet
above ground consistently disappoint me.
I offer no theories about the above observations. I only care what works in
practice and what doesn't. Local conditions and availability of materials have
more of an effect on the results than do all the computer simulations in the
world. You pays your nickel and you takes your chances!
73,
Larry - W7IUV
DN07dg - central WA
http://w7iuv.com
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