If only I had (or could get access to) a digital camera, this page would be a lot more interesting. As it stands, text will have to suffice for the time being… Update (February 9, 2002): Scrub that, now I've got one :-)
On the first run (with the tank circuit way out of tune and running with only six of the ten gaps), there was only a faint glow of corona from a breakout point I attached to the topload, and a fluorescent globe would light faintly at a few feet. As I brought it into tune, I eventually achieved a single frantic, but fairly thin purple streamer about 8" - 9" long, with the fluorescent globe lighting even brighter at the same distance I had it before. As I opened the gap up to eight gaps, the streamer length increased a little bit more. With the widest gap spacing of ten gaps (0.28" total), the best streamers were about 10" - 11" long, but the safety gap, previously quiet, was now firing every few seconds. Not wanting to risk blowing the transformer, I closed the main gap down a bit to nine gaps, which gave little decrease in streamer length. However, it cured the problem with my safety gap. I tried drawing the streamer to a grounded wire in an attempt to get longer and hotter sparks, but this didn't really work too well.
I also found that the coil doesn't break out at all without the breakout point, suggesting to me that the topload was too big for my coil (which I wasn't expecting). I am planning to try a smaller 6" diameter sphere as a topload.
Conclusion: I am pleased that my coil worked first go, even though the streamers are a bit on the short side for a 15/30 NST. I suspect that some of the energy that should be going into the streamers is being lost in my lossy saltwater tank cap, but that's OK for the time being.
Update (October 7, 2001): New pictures of the coil running at 900VA…
Still a bit short (my record is 14" to a grounded ladder)… I think that humidity has quite an effect on coil performance. At some point in the distant future, when I am able to afford an MMC and maybe a triggered gap, I hope to extract even longer streamers out of my coil…
Update (February 9, 2002): Here's some time exposures of the coil running with the saltwater cap:
Time exposures of the coil running with the new MMC will be up at a later date.
Update (April 5, 2002): Here is a shot of the coil running with the new ducting toroid, the MMC, and the RQ gap. It will be interesting to see how changing the RQ gap for a vac gap will affect performance.
Update (April 19, 2002): This is the coil running with the new vacuum gap:
Update (June 1, 2002): Another shot of the coil running with the vac gap. The streamers are brighter and more distinct in this shot, as they are hitting a grounded ladder. Click on the image to get a larger photo (approximately 305K):
Update (February 8, 2003): A similar shot from a recent run. Again, click on the image for the full-size picture (approximately 280K):
Update (March 22, 2003): An .AVI clip of the coil doing its best to fry the ladder can be downloaded here (2.9MB DivX, 320x240, 30 seconds, no sound)
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