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materials questions

 * Carbons Sent to: usa-tesla-at-usa-dot-net
                    chip-at-grendel.objinc-dot-com

Quoting tesla-at-grendel.objinc-dot-com (Chip Atkinson)

> I have a couple of questions that others could help me with.

Glad to help! I hope your recently completed coil project has
progressed to your satisfaction.

> 1) I have a bit of 18 ga. wire and was wondering if it would
> be suitable for a 6" or 8" coil.  Would it be better to get
> some 20 ga. wire instead? (I believe that 20 ga. was the 
> generally recommended size).

22 AWG seems to be the best balance of wire diameter to coil
inductance in 6 - 8 inch diameter secondaries. At nine or ten
inches you can go up to a 21 AWG, twelve inch diameter coils
scope out pretty decently with 20 AWG, and 18 AWG winds a perfect
aspect ratio 14 inch diameter secondary coil. Richard Hull's old
1/4 wave coil, Nemesis, was wound with 18 AWG magnet wire on a
14.4 inch diameter PVC thin wall "flume duct" coil form. The
aspect ratio was right about 3.0 with around 1000 turns on the
coil. Nemesis is one of the hottest 1/4 wave coil systems I have
ever had the pleasure to observe in person, they don't get much
better.

> 2) Am I better off with HDPE coil forms that are .33" thick 
> or acrylic forms that are .125" thick?  The HDPE will 
> be about 1/2 the cost of acrylic.

There really is no definative answer here I believe. Personally I
would go with the acrylic because it is easy to work with
(accepts a variety of adhesives) and it looks very nice. I feel
you would be hard pressed to measure a significant difference in
Q factors between identical windings on these particular coil
forms.

Richard Quick


... If all else fails... Throw another megavolt across it!
___ Blue Wave/QWK v2.12