Coil Construction, was: [AMRadio] Fun with 4D32's...

Brett gazdzinski brett.gazdzinski at
Thu Jan 4 13:35:08 EST 2007

thanks mucho for the info!
I printed it out, and will attempt to make a coil
about 12 to 14 inches long, 4 inches diameter, out 
of about #10 buss wire.

The original design in the ARRL 65 handbook calls
for a 3 inch coil of #14 for 250 watts of AM,
and I can run up to 700 watts of carrier, so
will go with #10 I think and make it 4 inches
in diameter, although I expect a lot of cut and try.

The design calls for four coils on one form, the
two inner coils 4 turn links, should I wind the coil
then cut, or try making them separate from the start?
The original design used B+W coil stock with 1/2
a turn unwound for the links...

I may have to make the caps as well, they call for
two dual 100pf caps at 4500 volts, plus a single
250 pf cap at 2000 volts, and I figure I should 
double the voltage ratings.

Fun with all thread and spacers, both metal
and plastic, using my collection of end
bits, plates, etc.
The caps might be the hardest part of the deal...

I have some big RF switches, a big chassis and
front panel, etc, its just the huge coil and caps
a high power balanced tuner needs that I have
to make.

Funds are tight right now, so I need to hold off
doing anything but plans and rounding up of
on hand parts, plus I need to buy wire to make
the antenna with, new rope, make the open wire
line (I got loads of wire and spacers).

I also need to buy a table top drill press,
I have been wanting one for a while, and
the plastic for the coils.

Thanks for the info!


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