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From: "Peter Martinez" <peter.martinez@btinternet.com>
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Date: Sat, 24 Jun 2006 11:54:15 -0000
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Subject: LF: Re: Top-fed LF antenna idea
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>From G3PLX:

I am sure Jim is right to say "it's not quite true..". As I suggested in my 
reply to Brian, if a lot of the field lines just 'short-circuit' back to the 
top of the tower, then there isn't going to be much contribution from these. 
But I think it's possible to believe that if we have a small monopole 
sitting in the middle of a square ground area which is the size of the top 
of the tower-block, initially at ground-level, and we then raise it by 
jacking-up the tower underneath it, our transmitted signal will increase as 
we do so.

It's well-known that you can work a lot further by taking a 2m handheld up a 
tower, but if you only think of surface-wave propagation theory, you would 
say that there wasn't any point in doing the same with a 136kHz 'hand-held'. 
If we can accept that the old Post Office work on the field-strength from 
ships is reliable (it's the height above the sea that counts, not the height 
above the transmitter), and we understand the mechanisms involved, we may 
gain quite a lot by taking, not just a small vertical monopole but any sort 
of metal object which can be deployed clear of the structure, to the top of 
something tall.

73
Peter