Loop size vs gain - question

dave-h

Newbie
Joined
Mar 15, 2021
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Is there a general rule for determining loop gain versus the size? I have an untuned 3 metre diameter octagonal shape moebius loop used for medium wave DX and I'd like to estimate the approximate gain I could expect if I increased the area.

The approximate area of the 3m loop is 7 sq. metres and a new triangular shape loop I'm building will be 47 sq. metres. I thought I saw references on the internet to somewhere between 12 and 15 dB every time you double the area of a loop but I cannot locate that information again after extensive searching. This no doubt referred to a tuned loop so untuned loops may well be different.

If this is true then could I expect something in the region of 30 to 40 dB increase in signal? Personally it sounds a little on the high side but I thought I'd ask here to see if anybody has experience with this.

Many thanks.
Dave
 

ka3jjz

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Jul 22, 2002
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Bowie, Md.
Dave this reflector on the popular groups.io listserver seems a very busy place, and maybe somewhere you can get some answers


This ain't Yahoo. I belong to several groups on this server and very little scam junk gets through. It depends much on the moderator, of course

Mike
 

devicelab

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Nowhere in WA
Is there a general rule for determining loop gain versus the size? I have an untuned 3 metre diameter octagonal shape moebius loop used for medium wave DX and I'd like to estimate the approximate gain I could expect if I increased the area. The approximate area of the 3m loop is 7 sq. metres and a new triangular shape loop I'm building will be 47 sq. metres. I thought I saw references on the internet to somewhere between 12 and 15 dB every time you double the area of a loop...
That seems pretty large but I guess it depends on the specific frequency range you're working. I have a fairly large delta-loop-like antenna that is about 200ft of 14ga wire into the Wellbrook ALA-100LN.

I tried the recommended loop size of 10-15m a few years ago. The difference between the two was quite significant; however, I wasn't looking at MW frequencies. On general shortwave frequencies (3.5-20Mhz), it was pretty incredible.

Shortly after, the noise appeared... and conquered all. :mad:
 
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