There ain't no such animal.
But if there was, it might just look like this:
(For government work, consider 1m (1 meter) to equal about 3 ft.)
Background: Here in Germany, the powers that be decided years ago to create
a Field Day class for "Limited", meaning limited antennas (i.e., no beam).
Specifically they stated only ONE antenna, and only two elevated supports,
maximum 15m high.
Initially, most people began with a Windom. Well, it worked - but that's
about it.
Our FD contest covers the ham bands 160/80/40/20/15/10 meters.
We designed the following antenna:
A double dipole, fed with openwire, consisting of two radiators fed in
parallel.
The top radiator was 60m long (2x 30m) and was primarily foreseen for 160m
and 80m work.
Each side of this dipole had a jumper placed at 17m.
For daylight work, we opened the jumper, creating 2x 17m.
At night we closed it, creating 2x 30m.
The lower radiator was 18m long (2x 9m).
This antenna gave us excellent results on ALL bands, and you can forget
about those strange radiation lobes that Wes was talking about.
In his previous post, Wes, N5WA cautioned (correctly so) us to model the
antenna before installing a second antenna at 90 degrees.
His argument about the strange lobes we could obtain at higher frequencies
is justified.
Wes, you can install two of my antennas at 90 degrees and forget your
modeling software. It's gonna work.
Just switch between the two antennas and one of them will bring in a great
signal.
Unfortunately we haven't found a way to avoid manually setting the tap on
these so you do need to run outside and adjust the tap, but this is only
twice a day, once in the morning and once in the evening.
Now feed this beast with openwire and an automatic tuner and you're in
business!
By the way, the Field Day class in question here has been won every year
(except the first) using the antenna I just described. Twice, I was
personally on the winning team.
Hope you guys found this interesting and maybe it's food for thought for
your own invention.
73
Rick
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