Topband: Shape and height of K9AY loops

[K9AY]

Pete,

1) Larger size increases the signal strength, but may reduce F/B on 80M. If your emphasis is 160M, the loop can be much larger, up to 1/4-wave of wire. The optimum terminating resistance will change a bit. 

2) Shape affects the elevation of the rear null. In general, a wider loop lowers the null. No problem if the bottom wire is horizontal. The loop can be almost any shape -- it's the enclosed area that matters most.

3) Height is not important, but you can raise the loop to clear clutter. Just keep the ground wire vertical.

So, if you go to 31 ft height, make the loop +/-20 ft wide. You'll be happy on 160M. May still be OK on 80M.

73, Gary
K9AY

____________________________________

I don't think I've ever read anything about this.? Just rechecked the 
Array Solutions manual and found nothing.? Reason for asking is that I 
have to replace my fiberglass mast, and while the old one was about 25 
feet tall, the new one is 31.? That raises the possibility that I can 
put the bottom of the loops 5 feet higher, or change the shape of the 
loops, which currently have their bottom legs more or less parallel to 
the ground.

Diagrams I have seen generally show included angles at the outer points 
of each loop to? be well under 90 degrees, and the lower segments almost 
parallel to the ground.? Has anyone experimented with this? What about 
the usual shape, but higher off the ground?? I have 4X30' radials plus a 
ground rod, with the radials laid under and in line with the elements

-- 
73, Pete N4ZR



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