[Antennas] Inductors

[Chris BONDE]

Info needed for inductors or loading coils.

If a have a cylindrical form (say 1in dia by 12 in+ long) and wrap wire around the 
circumference of the form with so many turns per inch ( 8 per in). Then I would have 

L = 2 * pie * r * l * t/in  = 2 * 3.14159* 1 *12 *8 = 50.25 ft

Inductance = a**2 * n**2 /  (9a + 10 b) = 1* (12*8)**2/ (9 + 10*12) = 71.44 uh.

Now, if instead of wrapping the wire around the circumference, I loop the wire from 
one end to the other then back to the first end, then down to the second end, etc 
working around the circumference spacing the wire at 8 stands per in, I will use the 
same amount of wire.  What would the inductance be?

Breaking the form open and making a flat coil would give a preposterous 
inductance.  How would the inductance be calculated?  Maybe easily measured.

Anyone know?

Chris opr VE7HCB