Re: Stumped at first light

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Original poster: "J Dow by way of Terry Fritz <twftesla-at-qwest-dot-net>" <jdowphotography-at-hotmail-dot-com>




It sounds to me like you need a bigger primary. Your secondary coil will 
take a nock'n and keep on rock'n. It sounds like a champ. But I think you 
may need a bit more to play with (Or tune with) on the primary.
As for the cap size I would think the correct size for your trany is going 
to range form 10 to 20nf (at 15kv to 20kv to be safe). It has been my 
experience that a bigger cap goes well with a smaller primary.
If you can't get a large enough cap you can add more turns to your pri coil 
to compensate. For my first coil I used wine bottle capacitors. My TC was 
similar to yours
3.5" by 24" sec coil wound with 24 awg
16 turn pri .5 cu tubing
15/30 nst
8, wine bottle caps (eventually I used 15nf of doorknob caps this worked best)
2, electrode static vac gap (this thing is the best static gap. It was 
better than all the other things I tried and I tried them all.)
I used whatever for a top load. All sorts of things. Big top = more primary
Small top= less primary. You should play around and see what works.

Because the bottle caps aren't the best caps ever and have a small 
individual capacitance I hade to use lots of them. A commercial cap will do 
you better but if your just starting bottle caps are the way to go. There 
cheep and easy and expendable. you can add or subtract them as you need. 
(Not being soldered together like in an mmc).
You will find that your gap is adequate but it can be better. I think 
improving the spark gap in any TC is the most effective way to lengthen the 
sparks. As it stands I would expect 8" to 12" sparks.
Hope this helps
Interested in the results
Read you later
Josh