Contemplating putting up three of these; with four wires out,
it would appear I could get 3 V-beams covering
a lot of azimuth, or nearly the entire compass as
a V-beam is bidirectional (no F/B advantage). With some
effort via bow & arrow, and grief, can probably get about
4 wavelengths of 40 meter band wire out, or about
560 foot legs. These would soar across a deep
ravine behind us, and tie to ropes strung out from tall
plantation wind break trees to our South. The wires must
clear tree tops which are growing down on the sides of
the ravine, thus the grief of stringing the wires! Idea is
to stand on my roof, and fire the tow tine carrying arrows
out 150 yards or so across the deep ravine in which trees up
to 70 feet tall are growing, and some how pull the wire
across, without it becoming entangled in the intervening
tree tops! A helicopter would get the job done in no time,
Anyway few questions I have of the wire antenna fans:
1. What type of wire should be used for such long spans?
The regular hard drawn #14 stranded antenna wire, or
something else; maybe the very flexible 126 strand antenna
wire. The hard drawn is something like $60 per thousand
feet, while the super flexible is about $80 per thousand feet.
I read somewhere that if there is a chance your
very long wire antenna would intermingle with tree limbs/
leaves, was a good idea to use insulated wire -- regular
#12 or so stranded house electrical wire? Seems
to me this would be too heavy. Stranded #14 copper wire
weighs around 18 lbs for 500 feet, I think.
2. Appears it will take some kind of "at the feed point" switching
to switch among 3 V's. They would be fed with a 600 ohm, home
made ladder line. It seems the ladder line must be switched from
wire to wire, to select which of the four wires, running out at
about 50 degree angles to one another, would form the particular
beam wanted at the moment. Not sure how to do this.
Without some switching set up, it looks as if two more long
wires would be needed to form three completely separated
V's, each with its own ladder line down to the shack area where
the desired ladder line could be selected.
Have been told 1/2 inch PVC pipe would make excellent
ladder line spreaders, about 6 inch long pieces. Is this good
3 Is the Amidon 50ohm:600ohm balun the best way to get from
my 50 ohm antenna tuner to the V's, or build a special balanced tuner?
The balun is priced at about $200. Unfortunately, the ARRL Antenna
Book is a bit thin on info about ladder lines, balanced tuners, and
V-beam info these days.
4. What is the best sort of tow line that an arrow could carry, and then
later be used to pull several pounds of copper wire? Probably have to
be a series of lines first, until at last a rope has cleared the needed
path. Feb. '97 CQ has a nice article by AD4UA about sling shot and
cross-bow use for antennas in, over and above tree tops. Herb mentions
a gadget the archers use during hunting called a Game Tracker. This
device mounts on the hunter's bow, attaches a light line to an arrow,
and out it goes. The idea is that the hunter then follows the line to
wherever the game has wandered and, at last fallen. No one on Kauai
ever heard of such a device. Wonder how long and heavy the line
within/from the Game Tracker might be? Herb's piece does not
mention this detail.
Obviously I will only put up one V to start; this will demonstrate
if it is even possible in the situation here. This will be pretty much
a North-South antenna. Much of the world of interest to Hawaiian
DXers is to Asia and Europe across the Northern area; however, most
of us have learned that the best path for nearly all the world within
the Northern Hemisphere is the Long path, all over water to the
South, not across the North pole area. With all three V's, the gain
on all the HF bands, even 160 using 560 or so foot long legs would
be a lot of fun to try; even just fed Zep style to single long wires
could be interesting.
Anyway, appreciate any comments and advice from those who have
already put up and used long (multi-wave) wire and V-beam antennas.
Mahalo and 73 from the Garden Island of Kauai
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