In article ,
NoSPAM wrote:
"Bob" wrote in message
...
anybody have any airdux (or similar) coil stock they wish to part with
(cheap)?
Looking for something #16 wire, about 2" diameter, maybe 3" long. Needs
to be about 10 turns per inch.
Actually, if is is 2" diameter and 10 TPI, I need a 2" chunk for the
13-ish uH needed.
It's for a 6146 homebrew transmitter final amp.
tnx,
Bob
kb8tl at yahoo dot com

Have you ever thought about winding your own? Find something of the right
diameter - PVC pipe, wood dowel, cardboard roll, etc. Wrap it with waxed
paper, then wind the wire on it tightly holding the ends down with tape.
Mix up some epoxy (24-hour cure will be stronger and more flexible, but
5-minute epoxy will also work). Apply the mixed epoxy to your coil in
lines about 1/4 inch wide. Use at least six lines to make a sturdy coil.
Let the epoxy cure for several hours to overnight depending on the epoxy
chosen. Carefully withdraw the form and unroll the waxed paper from the
inside of the coil. It's really simple to do and you have a real homebrew
rig.

Make sure you use bare copper or tinned copper wire if you have to tap the
coil. If you use bare copper, do not use polyester resin instead of the
epoxy as it will not cure properly. I won't say why, but instead leave
this as a mystery for the readers of this newsgroup.

suggestions.

1) Fiberglass perf board is drilled on .1 centers so you can cut a piece
down the middle of the holes, a bit of hacksaw work if needed, and use
it as a comb spacer glued from the outside.

2) just cut several .2 inch strips of perf board with a row of holes in
the middle, start at one end and feed a preformed slinky of the wire so
that the strips space and support it.

2 is less work than 1, but it's real hard to get it nice looking.

3) Another way is to wind with a second wire used as an interleave,
hot glue both wires and then pull out the second wire, (insulated
which doesn't take the glue as well as the bare wire and stranded for
flexability), from the inside after removed from the forming dowel.
For transmitters, you'd probably need to treat the hot glue as a
temporary scaffold and use a better glue for the final structure.

Mark Zenier
Googleproofaddress(account:mzenier provider:eskimo domain:com)