Barry - In response to your query;
>What would you suggest in it's place given:
>
>1. Less than 100 feet long.
>2. Covers 1.8 - 30 Mhz.
>3. No antenna tuner.
>4. Feed it with coax.
>5. Put it up in an afternoon with a couple of poles.
>6. $200 or less.
>
A miracle! :^) No, make that several miracles!
Seriously, if you look at your objectives you must realize that you are
asking an awful lot of an antenna. I would like to suggest that you add
another criteria;
0. High efficiency
Multi band antennas are by nature compromises with a few exceptions. You
need to identify which compormises you wish to make. In chosing the B&W
antenna one loses efficiency, which in my opinion is one of the most
important criteria.
I know it is easy when answering "what do I want in an antenna" to reply
"the whole lot", but it is far better to sit down and consider the type of
operating you like to do before choosing an antenna; what bands you like to
operate on, whether you like to work DX or local, do you like to work
contests, and so on.
Big question; Do you really want a good antenna for 1.8 to 30 MHz
comprehensive coverage, or do you just want to work the Ham bands??
If you just want to work the hambands I can help. You will have to give up
one or more of the criteria you suggest though.
As a good general purpose multiband antenna I would suggest a 135 ft (more
or less) long wire end fed with an L network tuner, with a good
radial/counterpoise/ground system. This antenna is roughly an integer
multiple of a half wave on all ham bands above 80 M, and is a quarter wave
on 160 M. Erected as an inverted L with an vertical section of 35 feet or
more, this antenna meets all your criteria except 3. no tuner. It will
perform well on all bands, although you could erect an antenna as simple or
simpler for each band that would perform better.
If you still insist on no tuner, I would suggest that you purchase, either
built or as a kit, the LDG autotuner, or similar automatic antenna tuner to
use with this antenna. It is as close to a
"Inexpensive-tuneless-multiple-band-reasonably efficient Antenna" as you
are likely to get. A "Zipless Antenna" if you will.
The same tuner can be used with a ladder line center fed Zepp to accomplish
the same objectives, but the efficiency of a 100 ft wire will suffer on 160
M and a lot on 80M. On these bands it is better to tie the feeders together
and feed as a vertical T against a good ground. Also you have to deal with
tuning a balanced feeder with an unbalanced tuner, which can work, but is
not the best way to do things.
In my opinion, If you are willing to put up more than one antenna and deal
with the switching, you will have a better antenna system.
Vertically polarized rectangular loops are good performers at moderate
height for 80 M and 40 M. A loop 14 feet high and 56 feet long will give an
excellent account of itself on 40 M and equal most ground mounted verticals
and best dipoles erected below a half wavelength for DX. Double the
dimensions for 80M. You can squeeze the long portion a bit (take up the
excess in the vertical legs) to get the dimension under 100 ft for 80M.
These antennas will load up OK on other bands, but the radiation pattern
can leave a lot to be desired.
Parallel dipoles are good performers and are relatively easy to tune if the
bands are restricted to those that are harmonically related, 80, 40, 20,
10. If these are erected at less than a half wavelength they will have a
high angle of radiation and be mostly useful for close in contacts. You can
pull the same trick of tying the feeders together and feeding it as a
vertical against a good ground system for DX though.
Loops (in the vertical plane) fed with ladder line and a tuner are nice
multiple band antennas as long as the circumference does not go above about
7/4 wavelengths or below about 3/4 wavelengths.
If you like DX, consider a wire yagi for your favorite band pointed at
South America, Europe, or the South Pacific for lots of fun cheap. This
should be easy on 10 M, and you will have a ball, particularly during the
10 M contest.
A two element Yagi for 10 M and 20 M can be made rather easily if parallel
dipoles are used for the feed and separate reflectors used.
Many rigs have band information on the rear that can be brought out and
used to automatically switching antenna, again allowing several antennas
to appear as a single one.
There are other ideas as well. Look in the Handbook or on W4RNL's web page
for more ideas.
I hope that this has been useful enough to you (and maybe Dave) to justify
its length. There is no free lunch. - Dr. Megacycle KK6MC/5.
James R. Duffey KK6MC/5 DM65tc <jamesd1@flash.net>
30 Casa Loma Road
Cedar Crest NM 87008
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