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[Amps] Hi-Q RF Coils

To: <amps@contesting.com>
Subject: [Amps] Hi-Q RF Coils
From: EVonvaltie@aol.com (EVonvaltie@aol.com)
Date: Thu, 28 Nov 2002 14:28:57 EST
I am trying to find the best way to build RF inductors in the range of 5-50 
uH and the lowest possible losses. They are for use at KW+ power levels, such 
as might be found in tank circuits and antenna matching networks.

I would like to hear any opinions. enlightened or otherwise, in response to 
the following question. For a particular inductor, for use at 3.5MHZ, the 
nominal required coil data is 12turns of #12 wire on a 1.5" form, close wound 
(about +j100 at 3.5). What would be the difference between winding with #12 
magnet wire vs. a Litz weave having the same copper cross section, using 
conductors of approx. 10% of the DIAMETER of the #12 (about .052"). I would 
like to know approx. how much difference there would be in the RF resistance, 
since the coil carries the full antenna current+. Any loss in the coils 
(there are several) subtracts directly from overall antenna gain so it is not 
a trivial issue.

I have found a way to make the Litz wire to my own specs as needed, but don't 
have much to go on for its theoretical performance. I don't recall ever 
seeing any of any value. Have you??

Eric von Valtier K8LV


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