• Install and arrange the system as it will be used. Break the secondary ground connection at the base. Characterize the system from the connection of the top of the secondary and base of the extra coil. Two resonances close to frequency “F” should be seen now. The higher frequency is the extra coil. Now add top capacitance to the extra coil until its dip merges to form one dip with the secondary. The system is now tuned close enough to fire it. Make sure to reconnect the base of the secondary to ground!
• The primary is usually tuned to a point around (.707 X “F”). Tune the primary to achieve the maximum spark off of the extra coil. It is important to minimize losses in the connection of the secondary and extra coil. I use a 3/4" by 6' piece of copper pipe to make this connection. If you use just a piece of wire, corona losses can be seen. Remember, that the current density in this wire is very high, even in a small magnifier, and losses are also higher in a smaller high frequency magnifier, so hold them down with a solid large surface area connection here.

We are still experimenting and already have a larger magnifier planned. We have found that magnifiers with couplings of .2 are easy to make by the average amateur but the voltage output is not much more than could be achieved by an ultra well designed Tesla coil! We find that for dramatic results, more power and tighter coupling are required. This requirement may stop all but the advanced amatuer from assembling large high power systems. More physical space is required also, but a small magnifier might be assembled in the center of a garage floor.

This article is meant to stimulate interest in and among amateur coil builders to construct and investigate magnifier type Tesla coils. Many of us have sat on the sidelines too long! We would like to hear from anyone constructing a magnifier system. We have tried to avoid a rigid inch for inch description of our system in order to inspire others to create their own system and not just copy a blue print. To assist the amateur builder or serve as a reference point to start construction, we are offering a condensed VHS video tape of our work in “free resonance” and magnifier systems for $25.00 ppd. (priority mail). This tape documents our early work and explains a lot of small details not able to be included in this short article. Send correspondence to: Richard Hull, 7103 Hermitage Road, Richmond, Virginia 23228.

Extra Reading and Magnifier Data Sources we Found Useful

1. TESLA TRANSFORMER CHARACTERIZATION Peterson, TCBA NEWS vol. 6, #2
2. COEFFECIENT OF COUPLING Cox, TCBA NEWS vol. 3, #2
3. REPRODUCING TESLA'S COLORADO SPRINGS COIL Corums, TCBA NEWS vol 7, #2.
4. TRANSMISSION LINE THEORY Corums, TCBA NEWS vol. 8, #4
5. LIGHTNING IN COLORADO Wysock, TCBA NEWS vol. 2, #3
6. TECHNICAL ANALYSIS OF THE EXTRA COIL AS A SLOW WAVE HELICAL RESONATOR

Kenneth and James Corum, Proceedings of the 1986 Colorado Springs Tesla Symposium.