K7ITM wrote:

A good web site for calculating the inductance of a cylindrical helix
is http://hamwaves.com/antennas/inductance.html. There's an
inductance calculator for cylindrical helix coils and toroid coils in
the RFSim99 package which you should be able to find for free
download. It may well be useful to you for other things, too.
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Tnx Tom for the above 'excellent' comprehensive web site reference.

Frank GM0CSZ / KN6WH