At 1:56 PM -0400 4/7/03, K3BU@aol.com wrote:
>Use plastic soft drink bottles....
For best Q, the coil should have a single-layer winding, be as large
as possible dimensionally subject to the requirement that its
self-resonant frequency be well above the operating frequency, and
its length should be between 50% and 100% of its diameter. The
conductor should be as thick as the length of the coil, the number of
turns, and safe interturn spacing allow. (Thus, you may be using
copper tubing rather than wire.) A 40-meter loading coil may be too
big to fit inside a soft-drink bottle.
Spreadsheets are available for designing coils. IIRC, QEX had an
article about this last year.
73 de Chuck, W1HIS
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