[Amps] 160M PI network Toroidal Coil

Bill Turner dezrat1242 at yahoo.com
Sat Oct 5 12:23:00 EDT 2013


ORIGINAL MESSAGE:          (may be snipped)

On Sat, 5 Oct 2013 11:28:13 -0400 (EDT), Louis wrote:

>Why not use a close wound wire coil. 

REPLY:

If you use either #4 or #6 solid bare copper wire it will be basically
self-supporting without the need of a core. Mount it with a ceramic standoff
at each end and possibly another in the center to give it a little more
rigidity. 

Wind it on a piece of 3 inch diameter pipe under as much tension as you can
and you will have a strong, stiff coil with plenty of current carrying
capacity. It will have essentially zero loss and none of the insulation
problems of a toroid, nor the cost of the toroid. 

According to K6STI's inductance calculator, a coil of #4 wire, 22 turns, 3.5
inch diameter and 6 inches long will give you about 22 uH which should be
about right. Wound on a 3 inch pipe, it will spring out to about 3.5 inches
when removed from the pipe. It will take about 20 feet of wire. 

The wire should be available at your local hardware or electrical store. 

The only question is will it fit inside your amp? I don't have one so I
can't help you there. 

73, Bill W6WRT


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