Q. If you haven't taken the plunge, I strongly suggest that you get on the Internet and at least tap into the Tesla list. The discussions are great and the amount of knowledge available is fantastic.

A. I agree that this new form of communication is the way to go. The problem I face is time. The newsletter takes up so much of it that I have been forced to give up several enjoyable avocations. What I see in the Internet is just another way for cutting into what little time I have left each day for attending to other life functions. In addition, the Internet is a sedentary activity. What I need is more exercise as a means for maintaining an acceptable level of health. Lastly, if the information is so “fantastic,” why not share it with our readers?

Q. I'm having my transformer rewound and want to immerse it in mineral oil. The man at the electrical repair shop said that mineral oil was not the right kind of oil to use for this purpose and that only commercial grade transformer oil would work well.

A. I've never made a comparison test between the two insulating liquids. However, I have used mineral oil as an electrical insulation on several occasions and found it to be most suitable for the purpose. In addition, mineral oil has been used by coilers for years without reporting any negative results. And I may even have an old transformer catalog which advertises “Insulated with mineral oil.” Perhaps, others with more experience in this matter will offer information based upon their experiences.

Q. I ordered a copy of the National Tesla Coil Parts Source Directory from Jeff Baker...I was wondering if you had seen this directory before allowing the advertising...Mr. Baker did little more than go thru an electronics industry directory and write down the names and numbers of companies that made generic components, with no specialization on high voltage or Tesla coils. I feel his advertising flyer was misleading in this respect.

A. It is a general practice for advertisers to forward a copy of the publication they are offering for sale. Jeff Baker did not provide this courtesy so I was unaware of the contents. I have had few complaints from readers regarding other advertisements and must say that most are reliable and provide a product as advertised.

Q. You mentioned that you preferred to tune a coil by using a variable cap at lower power to get the best tune point, then substitute a fixed cap for higher power. It seems that final tuning adjustments would have to be made at full power to compensate for spark and ion cloud loading effects.

A. Yours is a good and correct observation. How much of a final adjustment would have to be made would be dependent upon the size of the coil and the power involved. The need for final adjustment might not be required in small systems. Anyway, a variable cap tuning system would not apt to be used with very large systems because of the need for a sizable variable capacitor to make significant effects in the tuning process.

I might add that the resonant point of a coil can be sensitive to other effects such as changes in position in a room (toward or away from a wall or other surfaces having capacitive characteristics). And this can even show up in small systems. One of my coils was so sensitive that I could bring it in and out of resonance by merely changing my distance from it (or making a motion with my arm). Just goes to show that there are many complexities involved with Tesla coils.

Q. In regard to your preference to tune coils using a variable capacitor, what about variable coupling?

A. There's no better way to tune your coil's mutual inductance coupling than by using a continuously variable system. You are not only getting the most effective mutual inductance but at the same time will be tuning your mutual inductance to the characteristics of the spark gap.

Q. In some of the photos of Tesla's Colorado Springs magnifier, there is a strand of wire on insulators at the top of the secondary coil. One can detect a corona coming off of the wire. What was the purpose of this extra turn?

A. Many coilers interpreted it as a protection system used to prevent discharges from striking the secondary. The wire would absorb the strike first and then carry the currents to ground. But there appears to be more to it than that. Some researchers suggest that the top turn was actually carrying a current at audible frequencies (some guess at about 5 kHz). At this writing, the purpose of the coil remains a mystery.

Q. Nikola Tesla sporting a straw boater? Help, somebody.

A. I assume you are referring to the sketch at the bottom of the Volume 15, #3 cover. See our cover for Volume 10, #3 as well as the photo section of Margaret Cheney's MAN OUT OF TIME. Tesla, did indeed wear a straw hat.