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Old November 17th 07, 07:39 PM posted to rec.radio.amateur.antenna
Richard Clark Richard Clark is offline
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First recorded activity by RadioBanter: Jul 2006
Posts: 2,951
Default Low Noise receiving Loop antenna

On Sat, 17 Nov 2007 09:07:58 -1000, Tony Giacometti
wrote:

Let me guess. It is a shielded loop. You forgot to leave a gap in
the shield.


it is a shielded loop and no the gap is there, thats why I am wondering why
its not doing what I thought it would do.


Hi Tony,

It is working perfectly! It is working exactly as it was constructed.

You got your plans from the wrong source (or misread them, or failed
to follow directions).

There are several ways to construct one correctly, so I won't go into
those variations. There is probably a fix to the one you have, but
that is shooting in the dark.

Let's simply investigate the quality you seek. Low Noise comes only
from the antenna's quality of yielding the best dipole performance
possible under the circumstances. As these circumstances often
involve use in the low frequencies, the traditional high elevation
long-wire dipole is usually not an option. Further, if it is, it
rarely allows for rotation. What is usually within the user's skill
or available space renders a dipole that suffers from the proximity of
"things." These "things" disrupt the balance, and hence the
directionality of the dipole; thus noise sensitivity rises (noise
fills in through what should have been nulls in the dipole pattern).
The user still cannot turn the dipole and thus the long-wire in the
garden is a mediocre performer at best, and is usually a
disappointment all around.

Enter the loop.

The traditional loop for low frequency use is in fact quite small. By
being small it suffers less in relation to the proximity of "things."
This, of course, is if you erect it in the same place as that
long-wire disappointment you tugged down. That is, the loop improves
only in comparison; fortunately, it also brings the virtue of being
rotatable. That would be enough, but the snake oil salesmen like to
guild the Lily.

Enter the shielded loop.

The shielded loop solves a problem, certainly. That is the problem of
balance. However, if you use careful crafting of a simple loop, you
don't have any problem to solve.

There are many other details to sort out. That can be left to other
correspondence.

73's
Richard Clark, KB7QHC