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Re: [TenTec] Horizontal loop for 80m

To: "Discussion of Ten-Tec Equipment" <tentec@contesting.com>
Subject: Re: [TenTec] Horizontal loop for 80m
From: "Steve N4LQ" <n4lq@iglou.com>
Reply-to: Discussion of Ten-Tec Equipment <tentec@contesting.com>
Date: Fri, 3 Jun 2005 21:18:03 -0400
List-post: <mailto:tentec@contesting.com>
You will find references here:
You can view these only if you are an ARRL member.

My loop is cut for 80m at 3550. It is horizontal and 50' above ground at all 
points. It is supported at 3 points, thus a triangle. Made from 14ga 
insulated electrical wire.
At the corner feedpoint I have a 4:1 current balun. Either the Radio Works 
or W2DU version is fine since there are no really high voltages involved.
I feed it with about 75' of RG-8. SWR on the low end of 80m is 1:1. The 40m, 
20, 15 and 10m SWR is also 1:1.
30m is 5:1, 17m and 12m are 2:1. The internal tuner easily handles those low 
swrs on the WARC bands.
Modeling programs show that a triangle shaped horizontal loop has more lobes 
than the typical square loop thus this tends to make a better omni 
directional antenna on all the harmonics. Square loops have a rather strong 
lobe opposite the feedpoint which tends to dominate.
At 50', the radiation angle on 80m max is 90 degrees making it great for 
200-600 miles at night however I have worked some dx. On 40m, the max angle 
drops down to about 45 degrees making it a good all around antenna for both 
local and dx work in any direction.
On 14mhz and higher it becomes a great omni directional dx antenna with very 
low angles.
The same plan can be scaled to 160m although you can expect the swr to be 
higher on 160 due to the relatively low height. I have tried several 160m 
versions using various feed methods including open wire feed and performance 
is slightly poorer than a simple inverted vee on the top band. It's simply 
too low unless you can get it up to about 90' which would be a tall order. 
The 160m version when used on 80m does rather well for dx since the max 
angle resembles the 80m loop being used on 40m.
As for a multiturn loop with only 2 or 3 turns....I've never seen or read 
about anyone doing it. Keeping those wires spaced evenly could get 
interesting. What you could do is take a regular 80m dipole, feed it with 
open line and form it into a shape to fit the back yard. I somehow believe 
this would give you less trouble than doing the multiturn thing.
BTW: Lowes sells plastic pulleys for clothlines that are great for the 
corners. They last forever, make good insulators (no metal), and allow the 
loop to slide around as the trees sway.

Steve Ellington
----- Original Message ----- 
From: <Able2fly@aol.com>
To: <tentec@contesting.com>
Sent: Friday, June 03, 2005 7:01 PM
Subject: [TenTec] Horizontal loop for 80m

> Has anyone ever  tried a multi turn horizontal loop for HF  transmission 
> and
> reception? I can't recall having heard mention of anything like  that 
> being
> done. I'm talking about 2 or 3 closely spaced turns that resonate on 
> (say) 80
> meters, at a height of 25 ft or so. I guess if it were feasible, people 
> would
> be doing it. I know I could just give it a try, but thought I'd ask  here
> first in case I am considering trying  something previously proven not to 
> work...
> Thanks
> Bill  K3UJ
> _______________________________________________
> TenTec mailing list
> TenTec@contesting.com
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