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Re: Primary Coil Topologies Part 2/2




Jim,

It is possible to build such a coil.  Use an iron core to get the inductance 
up quickly.  The number of turns would be horrendous.  I knew an old radio 
amateur who did this a few years back to "listen" to the Shumman resonance 
frequencies (with recording pen oscillogrph, of course).  I can't remember 
the old fellow's name, sorry.  I beleive he used about 37,000 turns of #44 
wire on a soft iron core of 2 " diameter.  This hummer is very directional!! 
 The final tune would be with rather large swicthed capacitors across the 
coil.  The Q of the circuit is low, but the received power levels are 
usually quite high at this frequency.  Dropping a modern 
Neodymium-Iron-Boron magnet on the floor at a thousand paces will take out 
the front end of a snesitive amp hooked to this thing!  This is for 
reception only.  To make a TC at this frequency..... well, you are on your 
own.

Richard Hull, TCBOR
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From: tesla
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yiorgos
Subject: Re: Primary Coil Topologies Part 2/2
Date: Friday, March 22, 1996 8:34AM