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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
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.
----- Original Message -----
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
> reception? I can't recall having heard mention of anything like that
> 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
> 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
> Bill K3UJ
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