>From: David M. French, dmfrench@flash.net
>
Dave,
Your situation sounds very similar to my own - small lot with few or no
trees.
>While looking for a minimum-cost option multiband antennas, I found article
>in the 1988 ARRL Antenna Book in Chapter 5 on Loop Antennas entitled "Loop
>Skywire." The article references 1985 QST information from Dave Fischer,
>W0MHS. It describes what sounds like a very effective antenna. It is a
>horizontal loop, multi-band (3.5-28Mhz), coax fed (no balun nor special
>matching was recommended), 272' square, and supposedly very effective if
>operated at 40' in height above ground.
For several years at my old Stone Mountain location, I used this very
antenna for all bands 80-10m. Mine was mounted somewhat low, at 15-20
feet.
My impressions? This is NOT a DX antenna at this height. For 80m, the
main lobe appears to be straight up, so you hear a lot of close-in stuff.
It does listen well, due to some rejection of common-mode noise. (Seems I
could always hear everyone when monitoring the 3905 WAS net)
>I realize this will be a poor second to any tower plus yagi antenna station;
>yet it sounds like a great improvement over dipoles, relatively easy to
>assemble, and not overly obtrusive (would be largely undetectable view from
>street in front, but clearly visible from sides and rear). Has anyone had
>any experience with or knowledge of others about such an antenna?
I used this antenna for about 3 years. I replaced it with a 125 foot
doublet, fed with open wire. Why? Like most horizontal antennas
relatively close to the ground (in wavelengths), the loop skywire is
more effective if it is higher. The higher the better, and the height is
more critical than any other dimension. The skywire took 4 supports, a
dipole only 2. I managed to get a dipole at 45 feet. I found it much more
effective than the skywire on both 80 and 40m.
My advise. Forget the skywire. Put up a dipole at the same height. If you
have one or two supports high enough, consider a delta loop (which is a
loop skywire mounted vertically).
(I'm currently using a 125 foot doublet, 15 feet up. Two tribanders are
in the garage. Disassembled)
Bill Coleman, AA4LR Mail: aa4lr@radio.org
Quote: "Not in a thousand years will man ever fly!"
-- Wilbur Wright, 1901
--
FAQ on WWW: http://www.contesting.com/towertalkfaq.html
Submissions: towertalk@contesting.com
Administrative requests: towertalk-REQUEST@contesting.com
Problems: K7LXC@contesting.com
Sponsored by Akorn Access, Inc & KM9P
|