On Jul 3, 2010, at 6:11 PM, Charles Moizeau wrote:
> At my QTH in NJ I have the capability to mount a 500-foot,
> two-line, reversible Beverage running NE-SW.
> However, I am hesitant to undertake this project because the antenna
> would be entirely in the woods.
> Because of the deer, the Beverage would have to be at least
> six feet high.
My Beverages (which are around 300 feet long) are 8 to 10 feet
high because of the _people_ who walk in my woods.
> Two questions:
> 1) Would the antenna, 500 feet
> long, still be reasonably effective at that height?
My Beverages -- though somewhat shorter -- are quite effective
compared to my 1-element omnidirectional vertical TX antenna.
> 2) Would it be able to
> receive an adequate signal in the described woods?
My Beverages do when connected to any reasonably modern (last 75 years)
MF/HF receiver.
> For the record, I already notice that 16 in-ground radials,
> each 160 feet long and running entirely in the woods, produced very little
> change in the performance of my vertical transmitting antenna when they were
> added to an existing field of 22 radials, 60-120 feet long, installed in an
> open lawn area.
Nor did mine consistently appear to when I augmented my existing 22 (plus or
minus two) radials with a "few" more (another dozen, roughly). The woods here
have
nothing to do with it; I'm into the region of "diminishing returns" and the
trees are
orthogonal to the radials (except after a wind storm). Also, I notice you
live only a few miles from the Atlantic, and you have the "Great Swamp National
Wildlife
Refuge" to the northeast. Have you tried removing _all_ your radials? Perhaps
your
ground is so good you don't even need any at all. If you had a water well on
your
property, would the water taste salty?
Besides, how did you determine the impact of the additional radials
so as to eliminate variations in propagation from minute to minute or day to
day?
Do you have a motorized system for repeatedly rolling up and unrolling the
extra
16 radials in less than a second or two so you can do A/B comparisons, or some
other technique that eliminates the effects of other variables as much as
possible?
> I have tentatively concluded that the woods to the north are
> absorbing the radiation from my transmit antenna, and therefore the same kind
> of woods, lying to the south and east but more than 100 feet away, will
> seriously diminish the signal reaching the Beverage.
I, too, suspect the woods on all sides of my transmit vertical
may well "sap" my signal of some of its vigor but, on the whole, I am
extremely pleased with the operation of my transmit vertical on
160 with a paltry 22 radials, even though it is not a
full quarter-wave element. Would I get out better if my vertical
weren't surrounded by trees? Perhaps. So...should I cut down the
trees? Or move to an ocean front cottage so
I can have salt water under my vertical? Or quit my job so I can
sleep during the day and listen for DX more hours of the night?
What are your objectives and what price are you willing to pay?
If your trees are aluminum or some other metal, perhaps you have a
problem; mine are sappy pines with a few hardwoods mixed in, and
I don't feel the extra loss they _might_ be creating on the low bands
is large enough to motivate me to do anything different than I am.
Of all the things that keep me from working all the DX and being
top dog in the pile-ups, my woods are pretty far down the list.
Bud, W2RU
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UR RST IS ... ... ..9 QSB QSB - hw? BK
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