[TenTec] OT: Simple antenna software w/impedance

[Greg S]

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 at threshinc.com> wrote:

 Subject: Re: [TenTec] OT: Simple antenna software w/impedance
 To: "Discussion of Ten-Tec Equipment" <tentec at 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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