[600MRG] Lightweight coil construction

[Dick Bingham]

Sounds like a great idea BUT I am having a hard time envisioning
how one is going to route 16 * pi * D inches of wire between dowels
without tangling/kinking such a long length of wire unless the top of
each dowel is open.

If the top is open then it would seem that as you dress the wire from
dowel-to-dowel they will begin to pinch inward to make a tapered
coil.

Am I missing something here ?

Dick/w7wkr and xsh-26

On Thu, Jan 22, 2015 at 8:12 AM, Pat Hamel <pehamel at cableone.net> wrote:

> Some of you may remember that I used a suspended coil made of one layer of
> boat-building fiberglass and flat copper tape on 600 meters for many years.
> I used weed-eater line to take the weight of the lower part of the antenna.
>
> Building a coil that can be suspended and lighter than mine just jumped out
> at me when I was re-reading the first ARRL Handbook (which came with the
> regular hardcover handbook I got a few years ago.)
> The technique is called basket-weave, and should scale up to 630 meters
> easily.
>
> First calculate the ballpark inductance you need and the size of the coil.
> The length and diameter should be the same for best "Q".
> Mine was 16 inches in diameter and ended up slightly less than 16 inches
> long.
> Get your insulated wire and some tarred or otherwise UV-resistant tie cord
> (net making cord is fine).
> Get a board and a bunch of rods or dowels. Drill a circle of holes (an odd
> number) on the board to hold the rods or dowels upright.
> Fasten one end of the wire and wind wire in-and-out of the rods for two
> turns. The wires should cross between rods. Tie them together where they
> cross.
> Weave your way up the number of turns that you need, tying them as you go.
> Remove the dowels and you have a self-supporting, lightweight, low-loss
> coil.
> Spray paint to match foliage and set the knots, and hang it.
> My primary duty as caregiver has kept me from building the 600 meter SSB
> exciter, but I still monitor and hope to be back on the air
> I hope this helps,
> 73,
> Pat W5THT & WD2XSH/6
>
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