>From time to time I receive inquiries regarding
information on balloon supported antennas
for 160 meters. Here is a new resource.
In the 1996 issue of 73 Amateur Radio Today,
Stan Gibilisco, W1GV presents "a way to
really put out a big signal on 160 meters!" in
"A Kite/Balloon-Supported Zepp for 160 Meters"
He uses a 259 foot long antenna and connects it
via open-wire feed line to his transmatch. The
advantage is this antenna is less dependent
on radials to reduce ground loss. The disadvantage
is it can be hard to match the extremely high
impedance of the end fed half-wave antenna
to 50 ohms. The open-wire feed line adds
reactance at the feedpoint, according to Stan,
and allows him to match it, but "the bandwidth
is very narrow and the tuning of the transmatch
extremely sharp...If the operating frequency
is much different from the exact resonant
frequency of the antenna, the feedline will
become unbalanced and will radiate."
Stan presents useful info on how to attach
the balloon to the antenna wire- tether cord,
sources for balloons and helium (local
welding supply store), safety precautions,
applicable FAA regulations, and tips to
stabilize the balloon antenna in windy wx.
I use a 1/4 wavelength balloon supported wire
with 16 fifty ft. long radials on 160. It matches
directly to 50 ohm coax and is < 2:1 for 80 kHz.
With a decent radial system a 1/4 wave balloon
vertical performs well, and is a good choice for
a first balloon antenna on the TopBand.
- Jon NO0Y
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