Topband: QST Jun 06 RX Loop

Raoul Coetzee raoulc at
Thu May 18 13:32:19 EDT 2006

Tom wrote:


>I'm not going to debate the shield issue on this reflector.
>It is well past worn out, and it is very old established
>technology that no field (electric or magnetic) penetrates a
>conductive wall that is more than several skin depths thick.

Dear Tom: I agree fully.

>If you look at this page
>you'll see an explanation of fields.

I have looked (many a time!)and agree.

>The largest single problem is balance and feedline
>radiation. Tiny antennas have very small area and a very low
>radiation resistance.

Yes, again I agree.

>The largest single problem with a K9AY, Flag, the K6STI
>antenna, or even a small loop is that feedline connection.
>The K9AY works against ground, and if the feedline is
>"pumping" the ground at the antenna up and down with noise
>voltage that noise voltage will get into the antenna. It
>will with a small loop also....but not as bad.

>The key to a good receiving antenna in a limited space next
>to noise is having the antenna be the antenna, and keeping
>anything on the feedline isolated from the antenna.

Tom, I agree once again,therefore my second post stating that my
installation/grounding of the feedline  is suspect.

>There isn't any magic in what you see and it does not have
>to violate Maxwell's equations or the laws Faraday, Lentz,
>and others discovered.

Tom, under no circumstances did I try to argue with the  views of the
respected scientists/inventors mentioned in your post.
I keep the laws of physics  in high regard and were merely stating what I am
observing. This was in no way intended as some 'magical effect' observed by
me, in fact, I strongly object to the use of that term! I was merely
stating/asking what I am observing  in the context of the thread, and not
expecting to be reminded
of the fact that it was old school. :)

 >Odds are a dozen different antennas
>would work just as well if you decoupled the feeder properly
>at the antenna. The key is balance, and a bit of luck if you
>are trying to mismatch field impedance to a low or high
>impedance VERY local noise source.

Dear Tom, your last comment was all that was needed, confirming my
suspicions of poor balance in my own installation and trouble with my
attempts to have a reasonable station in a property of 40 x 20 metres!
Hope to work u again!


Please note my new email :raoulc at

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