H/D Aspect Ratio . . . How much does it matter ? ? ?

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Original poster: "Mccauley, Daniel H by way of Terry Fritz <twftesla-at-qwest-dot-net>" <daniel.h.mccauley-at-lmco-dot-com>



I'm currently designing my next secondary coil using 12" PVC pipe.  However
I've heard quite a bit recently regarding
what the best Aspect Ratio should be for this sized coil.  I hear some say
3:1 and then others are saying 4.5:1.

My question is what are the physics behind these numbers or has it been
found out experimentally.  Also, if I don't follow the rules, say build a
12" coil with a 3.7 or 4.0 H/D Aspect Ratio, would I expect my coil a
significant drop in performance (say greater than 25%) than if i built using
a 3.0 or 4.5 Aspect ratio.

Basically, does H/D Aspect Ratio *really" matter, or is it just one of those
things that if done properlyl increases performance only slightly.

Thanks again.

"Captain Corona"