[Amps] Re: compact coils...

[DF3KV]

>   "The 160 meter portion, even employing a reduced diameter
conductor,
> requires almost half the total space in a Pi-Coil.
>
>   Has anyone ever seen a multilayer approach to this portion of the
> coil?  For instance 3 layers spaced 1/4" apart radially.
>
>   Five turns of #8, space wound 5 TPI on each layer 1" wide at a
2.5"
> average (2" - 2.5" - 3" layers) diameter would provide something in
the
> vicinity of 17 uH.  This is approximately double the inductance of
the
> same amount of wire wound with at the same pitch in a single layer.
>
>   It might take a bit of creativity to wind but, with a suitable
form,
> it could be fabricated starting with the innermost layer at the
output
> end.
>
>   This approach would increase the interturn C somewhat but, I doubt
if
> that matters all that much on the "Topband"."

one approach reducing coil length could be this:

http://www.pbase.com/df3kv/image/34219012/large

73
Peter