We need to develop the Ideal Antenna!

[Mike Morrow-3]

Bob/AB5N wrote of an antenna for the KX1:
>I believe the criteria for an excellent antenna will be as follows:
> 1. Will match up well using the internal tuner on all four bands.
> 2. Has enough metal in the air to provide adequate microvolts to
>    the RX - to make it function well without being overloaded.
> 3. Provides some gain - or at least a clean predictable pattern
> 4. Is light, compact and easy to deploy.

Don/W3FPR replied:
>Some like the Carolina Windom, but I don't like any unbalanced
>antennas, and have a high preference for center fed antennas...

It sounds as if Bob is describing an antenna for portable use, such
as at a campsite or pic-nic area.  Regardless, I have played around
with antennas to use in such situations for more than 30 years and
wholeheartedly agree about both the generally unsatisfactory nature
of unbalanced antennas (especially for multi-band use), and the
ease-of-use plus very satisfactory performance of center-fed antennas.
I long ago settled on a resonant dipole as the ideal radiator for
this application.

>I would suggest a trap antenna with traps for 40 and 20 meters.
>Feed it with balanced feedline cut a half wavelength (or multiple)
>on 80 meters...

I dislike traps on my dipoles because of the way they narrow the
the range of acceptable VSWR, the complexity they introduce, the
weight and bulk they add to the radiator, and (when used with
simple QRP rigs that may have marginal harmonic suppression) the
manner in which they can be effective harmonic radiators.

>...build a coax fed trap antenna for 40, 30 and 20 meters (traps
>for 30 and 20), and carry along 2 33 foot lengths of wire -
>insulators on one end and an alligator clip on the other -
>add the wires to each end of the radiator.  ...carry that concept
>a bit further, and build the antenna for 20 meters with no traps
>and then add a set wires for use on 30 meters, another set of
>wires for 40, and yet another set for 80.

The approach that I found worked best for me was an antenna that
was a full-length 40m dipole (66 feet), with each leg broken in
six places with a home-made PCV tubing insulator with integral
jumper and clip so that the appropriate length dipole can be
established for all seven HF bands between 10m and 40m.  I built
the antenna for all these bands for use with any rig, not just the
limited coverage of a K1 or KX1.  It works better than any other
antenna I've ever used in a field environment.  It typically takes
less than a minute to alter insulator jumper configuration to
switch to another band.  It meets *all* of the desired criteria
listed by Bob, to which I would add "5.  Is very inexpensive and
quick to home-brew."  (I have a pdf file with construction details,
diagrams, and photos that I'll e-mail to anyone on request.)  I use
the technique that you suggest of attaching a 33-foot segment to
each leg for 80m operation, which is rare for me.

Mike / KK5F
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