In article ,
C. J. Clegg wrote:

Actually, what I mean is that some, including me, will be using 5-watt
radios (Yaesu FT-817). If the option of pouring 100W into any hank of
wire was available to all, the issue wouldn't be critical. It's not,
so it is. :-)

There's another approach to the antenna that you might want to
consider, _if_ the ALE ranges are limited to a few (say, no more than
four or five) and aren't too wide (say, no more than perhaps 5% of the
center frequency).

If your usage pattern fits this model, then you could construct a
multi-wire "fan" dipole array... simply a set of individual wire
half-wavelength dipoles, each cut for the center frequency of a given
ALE range, spread apart physically, and fed from a single coax at a
single feedpoint. They can be spread vertically (e.g. hang the
longest one as a flat-top from a convenient set of trees, suspend the
next-shortest beneath it on 6" spreaders, hang the next-shortest on
another set of spreaders, etc.) or horizontally (run one north/south,
another east/west, etc.).

There will be some amount of coupling/loading between them, so you'll
need to trim them for lowest SWR once they're installed, and you may
find the SWR bandwidth less than you'd get from individual dipoles.
Coupling/loading is greater for the vertically-stacked case, and less
for a star-like horizontal pattern (which takes more space and more
trees or etc., of course).

The nice thing about this approach, if it's suitable for your needs,
is that the losses are quite low. The wire which is resonant on the
band in question loads up and radiates, and the other wires (which
will typically have high, reactive impedances) accept very little
current. No lossy termination resistor is needed.

I've been using a three-wire fan dipole (5" vertical spacing) cut for
40/20/10 for several years, with very satisfactory results.

This approach won't give you continuous coverage of your 4:9 range...
unfortunately I can't suggest any which would, which don't require an
agile tuner/transmatch and which don't introduce high losses in some
portions of the band.

--
Dave Platt AE6EO
Hosting the Jade Warrior home page: http://www.radagast.org/jade-warrior
I do _not_ wish to receive unsolicited commercial email, and I will
boycott any company which has the gall to send me such ads!