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[TCML] New Resonator
Between work and other pursuits, I've been beavering away at a new resonator. Pics here <http://img576.yfrog.com/gal.php?g=hjv.jpg>
The secondary is mounted on 6" PVC (O.D. 6.5") and it's the one I wound a month ago. Now coated with 8 layers of Dolphs-AC3 and glowing beautifully.
The wife helped me with the primary today. It's 12 turns of spring copper interleaved with foam weatherstripping - exactly the same materials used by Terry Blake on his webpage for his "Huge Coil". Frankly, the closeness of the turns scares me, but Terry's power supply is much larger than mine and it works, so I guess as long as we're tuned correctly and don't overcouple, we should be fine.
My woman and I wound the primary on a 1" thick, 12" diameter circle of UHMW Polyethylene that I cut into a circle with the Jasper jig and my router. I'm learning how to handle that beast - basically to cut plastic you have to turn the speed down to about 1/2 way. Also, don't use a spiral bit that forces the material down. You have to have it spraying up into your face or the chips melt into a blob in the groove you're trying to cut.
The UHMW is bolted concentrically via nylon machine screw to a 25" diameter, 1/4" thick disk of polycarbonate - same as I used for my last primary. I cut a hole in the very start of the spring copper and the side of the UHMW disk, and tapped it for a 10-32 machine screw. Then I bolted the end of the spring copper to the disk with a nylon flat-head bolt. This prevented it running away, which it really did want to . They don't call it "spring" copper for nothing.
With the UHMW on the polycarbonate circle, and the end of the spring copper bolted on, it was simply a matter of controlling the foam weatherstripping and the copper and winding horizontally (winding axis vertical), by spinning the polycarbonate disk . Turns out the head of the nylon bolt acted as a pivot about which we could easily rotate the whole thing like a record (or a CD, depending on your generational proclivities).
After the winding was complete, I wrapped it with two interconnected 53" oversized "cable ties" I got from U.S. Plastics. Then I covered it with an 18" polycarbonate disk.
JavaTC says that the correct coupling for what I am trying to do is to have the base of the coil at about the top of the primary ribbon. I've found in my past construction that JavaTC tends to be a bit "optimistic" on its coupling calculations. On my previous tries, I had to undercouple just a bit further from what Java TC said. This arrangement will put the bottom turn of my secondary about 1.25 inches above the primary. If it needs to be lowered, well, it's a reasonably simple task to cut a 6.75" circle away the upper polycarbonate circle, or I'll remove the upper disk all together.
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