Marv talked about:
"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"."
73 & Good evening,
Marv WC6W
Hello Marv,
The early DX-100s used a honeycomb-wound 160 M inductor on a ceramic
tube form. I think the wire gauge was #14, cotton covered and doped
heavily. It was very compact. Now a days, I'd consider using a powdered
iron toroid for the 160 M portion of the pi net.
73, Roy K6XK
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