Tuning the tesla coil

I've completely constructed the tesla coil, and now I'm at the hardest stage of all, tuning it. To be honest, it's even harder than I thought. I succeeded in measuring the frequency of the primary and secondary coils. The primary seems to be around 700-800kHz, while the second around 1,1mHz. However, when I add a toroid-like dish or something to the secondary, it's frequency drops since I'm increasing the capacitance. The two frequencies almost match, but it still keeps giving me sparks of around 50kV, i.e. 5-6cm long. This is not how it's supposed to be... The coils are both very close to meet the same resonance, but there is still something that prevents the sparks from reaching long distances. One reason might be, that I'm using a fly-back transformer from an old TV. I'm using a 555 timer and power N-Mos transistor, to drive the transformer (there are more components, but they are irrelevant in this case, so I'm not going to mention them now). I also reduced the turns in the primary coil of the transformer and added a diode rectifier. So overall I get roughly 5kV, which is reasonable. Anyways, the spark gap is very well construced, I've made it, so that it can be easily adjusted with a screws. What I've noticed, is even if both of the 5nF, 6kV capacitors are connected in series, giving me a 2,5nF, 12kV capacitor, it still takes alot of time to fill up (judging from the slow frequency of the spark gap switching). I think thats also a reason, why my TC still gives me such weak sparks. One thing I might do, is increase the frequency of the flyback transformer, that will increase the current, therefore the capacitor will fill up more quickly. But then there's a chance that the transistor might blow (not that I didn't blow up 6-7 IRF730 transistors already, still wondering how this one is kept in one piece). Another reason for this awful appearence, might be that I'm using 28 gauge wire for the secondary coil (i.e. around 0.3mm). In the end I might be forced to rewind the secondary coil with thicker wire of around 27 gauge. Too many considerations, but I have alot of time, I'll do whatever is necessary for my TC to work. So, if you have any suggestions, share them with me, that may ease my work greatly :)

Back again

So I haven't posted anything for more than 3 months maybe, again because of the things I had to do at home, at school, etc. But now that I have finished this year of painful and boring studying in my ... well lets just say that my school is shitty, I'm free to start on my projects again. Really, the worst part was, that I couldn't concentrate alot on my projects, although I surely did some neat things, like a PC remote control (well not controlling anything yet tbh), some mind boggling game, I even made a primitive oscilloscope. I'm desperately trying to learn how the USB works, so I'll pretty much concentrate on that during the vacation. But just to get a nice "kickstart" on things, I decided to make something fun and not that useful or complex. A Tesla Coil - a device I always wanted to posses since I first started playing Red Alert 1. Classics never die ;) I'm still playing that shit. So I spent 2 days to find the proper materials. I found a nice plastic tube 12" high, 2" wide, just the right size of around 750-900 turns of 28 gauge copper wire for the secondary coil, and 15 gauge for the primary, 10-12 turns with 4" diameter. I also found 3 ceramic 5nF 6kV capacitors which I'll connect in series for a maximum of 18kV rating. I also found two 4kV microwave oven HV transformers. Now... all I need is to setup the coil, tune it and in the end I'll make myself a nice HV lightning show. Oooh can't wait, if you have any suggestions about the tuning, please post them here, would really appreciate it! ;)