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Re: Topband: 160 Receiving Loops source?

To: Eric Rosenberg <ericrosenberg.dc@gmail.com>, topband@contesting.com
Subject: Re: Topband: 160 Receiving Loops source?
From: "Richard (Rick) Karlquist" <richard@karlquist.com>
Date: Thu, 4 Feb 2021 16:41:09 -0800
List-post: <mailto:topband@contesting.com>

On 2/4/2021 11:27 AM, Eric Rosenberg wrote:
With my antenna supports gone and living on a small city lot (Washington, DC), I'd like to try an 80/160 loop.

I have some physical limitations that make mechanical skills mediocre at best for building one, and am looking for an affordable source for a built one.


Thanks & 73,
Eric W3DQ
_________________


Here is a loop design I published over 11 years ago:

http://www.n6rk.com/loopantennas/NCJ_loop_antenna_N6RK.pdf

This is a loop that is remotely tunable from below 160 meters
to above 75 meters, and it has a loop with a 20 foot perimeter.
This gives you plenty of signal so that no preamp (other than
the one in your radio) is necessary.  There was a group in India
building these a few years back, but I don't know the current status of
that effort. The contact person was Prasad VU2PTT (vu2ptt@gmail.com).

For marketing reasons, commercially available loops are:

1.  Untuned
2.  Cover 0.5 to 30 MHz
3.  Have a circumference of 10 feet
and
4.  Use a preamp

The need for the preamp drives up the cost considerably.
I purchased a Pixel loop like this to compare it to my design.
It turns out that the signal out of the 10 ft untuned loop is
so low on 160 meters that the sensitivity is limited by the
noise figure of the preamp, unlike my tuned design.

I realize I haven't given you a turnkey answer to your request,
but I at least wanted to give you the lay of the land.

At the 20 acre N6RK QTH, I have moved on from the loop and just
completed a 9 element, 290 foot diameter, circular receiving
array.

BTW, thanks for the DC mult in the recent CQWW160.  You
obviously heard well enough to go coast to coast, but
then, people tell me I have one of the louder signals from this region.

73
Rick N6RK
_________________
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