[TowerTalk] [Bulk] Re: Perpendicular Delta Loops

[Grant Saviers]

I did a lot of modeling a few years ago and found the tower interacts 
with the vertical polarization. If the loop is about 5 ft out from the 
tower then the pattern is improved.  A feedpoint about 20% up (from 
bottom) either leg yields a good low angle pattern and a near 1:1swr 70 
ohm resonance Z (apex at 77', bottom 118' long at 26')  There is about 
4db front to side and about 1db lower gain on the tower side of the 
loop.  2.33dbi peak gain at 20 deg which is pretty nice for a low no 
radial single support antenna on 80m. However, with the apex up it is a 
real cloud warmer on 40m.  If you have two supports, and have the apex 
down, the 40m performance is very good.  I've not modeled perpendicular 
loops but spent a lot of time modeling a phased pair, but gave that up 
with the tower interaction issues.  Others have built phased ones hung 
on a tower and reported poor results.

Grant KZ1W

On 8/23/2015 12:11 PM, Robert Harmon wrote:
> I would like to hear how your 80M Delta loop performs for you.
> I had one strung form my tower at 80 feet fed as Dennis said 1/4 wave from the apex.  I could work any DX that I could hear but it picked up
> much more noise (local electrical) than my inverted L I had up previously.   I was feeding with 450 ohm ladder line.  I am thinking of stringing it
> up again and this time feed with coax and see if it is better.  I suspect the ladder line was the culprit, not sure.
>
> Bob
> K6UJ
>
>
>
>> On Aug 23, 2015, at 11:34 AM, Dennis W0JX via TowerTalk <towertalk at contesting.com> wrote:
>>
>> Rich:
>> Check the patterns for an 80 meter Delta Loop hanging from a 78 foot tower. If you feed it at the bottom center for horizontal polarization, you will have a sensational cloud warmer and a poor DX antenna. This antenna should be feed 1/4 wave from the apex for vertical polarization.In that manner, the pattern is almost circular with about 1 to 2 db favoring the plane of the wires,
>>
>> You don't need the second delta loop.
>>
>> Dennis W0JX
>> Milan, OH
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