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From: "Ashlock,William" <William.Ashlock@edwards.boc.com>
To: rsgb_lf_group@blacksheep.org
Subject: LF: RE: Re: RE: Re: loops
Date: Thu, 7 Mar 2002 13:16:08 -0500
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Hi Dave,

>This sounds interesting. Are you able to model the "gain" of the loop
>against a 350ft inverted L fed against a 350ft counterpoise? Same amount of
>wire but not joined up...

I assume your 350ft is the length of the horizontal section? In other words:
the inverted L that would fit on my land, assuming I cut down all the trees?
:(   The length of the vertical portion is all-important at LF since the
signal is nearly 100% vertically polarized. Assuming 50ft, the loop could
beat the inverted L by at least 10db. I'm basing this on the basic 50ft
monopole (with long top 'capacitor') beating the 50/50 loop by the, pretty
much accepted, 6db. Then I'm adding 16 db to the loop for the stretched
horizontal dimension. 

(BTW: I'm not too keen on computer modeling for basic antenna comparisons.
My feeling is that good intuitive thinking is often lost) Modeling is great
for the +/- 1db details. 

>I just remember the great fashion of using loops on 160 years ago,

Oh, jeez, I first thought you were talking about loops 160 years ago! You
Brits aren't THAT far ahead of us! :)

>these were in small gardens and were about 60ft long and 25 - 30ft high,
small but
>still better in terms of wavelength than what you're proposing. These never
seemed to work any
>better than the equivalent inverted L.

Most likely 100% true. LF is a bit different. Because of the very strong
dependency on the complete system Q (ground loss, coil loss, and yes - tree
loss) the loop can come out the winner, particularly if your lot is a forest
of trees like mine. In which case, I just planted a wire or two over the
tops of them, and now, enjoy their presence! 

Bill A

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