Posted by
Terry Conboy on
Dec 22, 2005; 1:28am
URL: http://elecraft.85.s1.nabble.com/Horizontal-Loop-Antenna-tp384747p384752.html
At 11:58 AM 2005-12-21, Kevin, N8IQ wrote:
>I've been thinking about what kind of antenna to put up. With my height and
>deed restrictions, I'm quite limited. I've thought about putting up a
>horizontal loop antenna. Basically I was planning to run some enameled
>magnet wire around the perimeter of the roof (I have no plans on running
>more than 10 watts). The wire would lay under the shingles so it can't be
>seen. The antenna will be 1 WL long on 80 meters. I'll run coax down to the
>K2 + ATU.
>
>This is similar to "The Loop Skywire" described in the November 1985 issue
>of QST. Anyone have experience (or see a problem) with this antenna?
Kevin,
Just be sure that the high voltage points on the antenna are well
insulated from your shingles. The voltages are maximum at 1/4
wavelength away from point on the loop which is opposite the
feedpoint (and every 1/2 wl from those points on 40m and higher
bands). Even with 10 watts, you could see about 200 volts (rms) RF present.
When the shingles are damp, you may see a bit of detuning from
increased capacitive loading (and a little extra loss).
I used a 30 foot high horizontal loop (1 wl on 80m) at my Seattle QTH
and was quite pleased with its performance on 80m-10m. One side ran
closely parallel to the aluminum gutter above the second story. The
remainder of the loop was stretched to trees across a small
creek. Feed was through a short length of 300 ohm line and a
link-coupled balanced tuner.
The loop was originally made from stealth #26 magnet wire, which was
fine for RF (100 watts), but was often trashed by falling tree
branches. It was later upgraded to bare #22 and the mechanical
problems were nearly nonexistent (and it was still nearly
invisible). When I started to get ice buildup, I connected the loop
to a low voltage DC supply which warmed the wire enough to melt the ice off.
ARL 61,
Terry N6RY
_______________________________________________
Elecraft mailing list
Post to:
[hidden email]
You must be a subscriber to post to the list.
Subscriber Info (Addr. Change, sub, unsub etc.):
http://mailman.qth.net/mailman/listinfo/elecraft
Help:
http://mailman.qth.net/subscribers.htmElecraft web page:
http://www.elecraft.com