RF ground in an apartment.

May 21, 2007 20 Replies

I put a few pictures from my coiling days on alt.binaries.schematics.electronic Along with a bipolar coil which would be more suitable for an apartment

The induction coil was from the 1910 book "The Tesla High Frequency Coil," by Haller and Cunningham. It was a lot of fun to build.

The book is pretty amazing. These guys didn't go out and buy much - they made it from scratch. They give instructions on making the Induction coil to excite the Tesla coil, a magnetic gap, the laminations to be cut for a home made shaded pole induction motor to drive a rotary gap, electrolytic rectifier to use with a DC motor, etc.

Not having gutta percha wire, double cotton covered wire, hard rubber, etc.. I adapted it to what I did have.

I made the bigger of the two induction coils and wound it for use as an induction coil (3-4" sparks) running from 20 VDC. The turns ratio is about 1:60 and I was eating up condensors across the points of my interrupter because the peak was well over 400 volts. I tried it on all frequencies between 9 HZ and 200 HZ and found the best sparks at

88 HZ with a 30 uf condenser. (a car auto coil takes about 1/2 uf)

With three or (four) primary windings in series, I could operated it as a transformer running from 120 VAC with 7,660 (5,800) volts out and operating at 1KVA.

The secondary has about 13 miles of wire in it and if the resistance is correct, I nailed the calculated length of wire to within 300 feet! My turns counter was coming up short with each layer I wound, so I increased the number of layers per bobbin to compensate.

Total project took me 3 months winding the secondary only took a week.

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