Peter-
I had an almost identical semi-horizontal loop at my last QTH for years. Fed
with W7FG true ladder line, running right into the basement shack, thru a gap
in an aluminum window frame. Tuned with a Johnson Viking Matchbox. My loop
wire was about 274 feet, and the old JVM tuned it on all bands except 160M. The
ladder line was tied up near the ceiling, passing within inches of cast iron
Drain pipes, and steel heating/cooling ducts. I had 19 acres, and some nice
TALL trees, and hung MANY different wire antennas over time we lived there,
INCLUDING an 80M EDZ, and Jamaica, and Shirley arrays. From MY experience, the
loop I described was the best overall antenna I ever had in the air, for MY
operation style. NOT a DX chaser, although I worked a bunch. NOT a contester,
although I participated in a few to hand out some contacts. Most of my time was
on SSB NTS traffic nets on 40 and 80M SSB. I finally gave up trying to improve
on that antenna. MY experience. I suggest you just build that thing and get it
in the air. You WILL make contacts. If you are going to be a DX hound, I would
suggest a vertical, of some kind. For contacts inside 600-800 miles on 40 and
80, NO vertical will work as well as a cloud burner, overall.
You will notice MANY problems with my described setup. Some will probably
crucify it, in fact. Fact is, it WORKED. There were conditions at that property
I always wondered if, somehow, they made the loop work so well there. The water
table was quite near the surface, and our water had a very high iron content.
Wonder if it acted as some sort of "built in" ground plane, or reflector?!!???
My favourite quote on antenna "theory":
"Those who say it can not be done, should not interrupt those doing it."
Get that wire in the air, and report back!!!!
73-
Greg, KC8HXO
--------------------------------------------
On Mon, 7/18/16, Peter Klein <pklein@threshinc.com> wrote:
Subject: Re: [TenTec] OT: Simple antenna software w/impedance
To: "Discussion of Ten-Tec Equipment" <tentec@contesting.com>
Date: Monday, July 18, 2016, 5:38 PM
With all the discussion
of optimum antennas and transmatches, here's a
much more simple but related question:
Can someone recommend a
(preferably) free and reasonably simple program
where I could do some "what-if-ing"
with a horizontal loop?
Background: I want to set up a decent
multiband antenna. I used to
have a tree
in which I could hang a nice 80m inverted vee at 60 feet.
It worked well. Then the tree tried to
kill my house (fortunately, it
missed).
So the tree is now gone. I don't have anything higher
than
about 30 feet now. It seems like the
best antenna for me will be a
horizontal
loop fed with 450 or 300 ohm line. Maximum circumference
will be about 220-240 feet around my
backyard. Probably 30 feet high on
one
side and 10 feet high at the back fence. Before I start
buying
wire, poles, etc., I want to model a
loop at the various possible
lengths/heights and get an idea of what the
impedances, reactances and
angles of
radiation will be on the various ham bands.
I was fooling with 4Nec2, but
found it too difficult to use--it seems to
assume that you know everything about the
minutiae of advanced, complex
antenna
design before you start. And trying things out led to long
slowdowns on my relatively recent PC. I
just want to be able to tell
the program,
"here are the lengths of the sides, the heights, the
frequency, maybe the transmission line.
Now tell me the impedance,
reactance,
angles of radiation, losses are on 80m. Now how about on
40m, 30m, 20m, etc.?"
Thanks and 73,
--Peter, KD7MW
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