[Elecraft] grounding and counterpoise

[Augie Hansen]

Hi Ron,

You gave a nice summary of the antennas used on boats and aircraft in
response to the question asked by "mc". I especially enjoyed your
description of the Zepp, an excellent but often misunderstood antenna.

There are a few other antennas that have been and are used on airplanes that
I have learned about over the years. In the late 1970s I was working at Bell
Labs in NJ and got to work with AT&T's "air force" regarding flight
operations manuals and such. They flew a number airplanes including some
Gulfstream 4s and several smaller corporate-type jets. In discussions with
the pilots, some of whom had been pilots for the commercial airlines, these
additional designs came to light.

1. The leading edge of the vertical stabilizer is typically an insulating
strip that either contains a wire or metal bar that is used as a short
vertical fed by a wide-range ATU that covers HF and/or VHF frequencies.

2. The insulated leading edge can instead be used to form a tunable slot
antenna. The gap so formed is effectively embedded is a large, although not
infinite, metal surface. The length of the slot and the position at which
the slot is fed can be varied to adjust the resonant frequency and matching
condition.

3. Just yesterday I was having lunch with a corporate pilot and a few other
ham friends. He said another technique is to run a wire from near the front
of the plane to the vertical stabilizer tip to form a loop consisting of the
body of the plane and the wire. I presume the loop is fed by an ATU,
probably installed inside the vertical stab or near the nose with one side
tied to the plane's metal shell and the other to the wire.

I'm sure there are many other ways to put an antenna on a boat or plane that
we haven't mentioned yet, and others yet to be dreamed up.

Cheers,
Gus Hansen / KB0YH