Dunno how accurate you need it to be "as wound", and dunno what sort
of form factor you want, but if an air-core coil will work for you,
here's one way: get about 18 inches of 18AWG wire, nice and straight,
and a 1/2"x13TPI bolt. Wind 11 turns of that wire into the threads of
the bolt, leaving 1" of wire on either end (or start with a longer
piece if you want longer leads), and unscrew the bolt. The result
should be a coil about 0.85 inches long and 0.424" ID, and 0.600uH.
When you get it mounted near other things, the inductance will go down
a bit, and you can adjust it down further by stretching it a bit. The
Q at 14MHz should be just over 200. Or you can use 10 turns of 16AWG,
done the same way, which will have a slightly larger ID, 0.434 inches,
and about 0.561uH nominal and very slightly higher Q.

In general, the L = (n*r)^2/(9*r+10*l) formula works well, where r and
l are radius and length in inches, n is number of turns, and the
inductance, L, is in uH. My numbers above come from a program that's
easy to use and that I've learned to trust from verified results.
It's convenient to use a bolt to get consistent spacing and diameter,
though for high stability, you'd want some sort of support. For
highest Q in a given volume, go for a coil with roughly equal length
and diameter, though that's not terribly critical.

Cheers,
Tom


"jim&julz" wrote in message ...
Greetings.

I have a pixie 2 xcvr currently set for 80m. I have been wanting to put it
on the 20m band, so I found that I require a .551uH.

I assume that this would be a terribly easy coil to wind, but I've never
wound a coil w/ intention of achieving a specific inductance. If anyone is
familiar w/ the number of turns/gauge etc... for a .551uH inductor, I would
really appreciate that info.

Thanks much.

James Shrum - KC9FFX