[Prev][Next][Index][Thread]

Re: Reading List


Quoting msr7-at-po.cwru.edu (Mark S. Rzeszotarski, Ph.D.):
Quoting Richard Quick:

MR>My question to you is this:  I am trying to gain better
MR> insight into the understanding of the extra coil.  I understand
MR> the Corum brothers have written some on this, as well as some 
MR> others.  Can you point me to which Corum (and other) 
MR> publications discuss quarter wave helical resonator theory and
MR> extra coil math?  At this point I have been reading as much as
MR> I can, as I like to understand the theory behind the machine 
MR> before I spend too much time constructing one.

RQ>I have been around on this one. You are not the first to ask this
RQ>exact same question: 

RQ>VACUUM TUBE TESLA COILS

RQ>Probably contains the best available mathmatical explanation of
RQ>extra coil functions in Tesla RF power processing systems. If you
RQ>don't have a copy, I would get one.

Vacuum Tube Tesla Coils certainly contains a lot of equations, but I
think if you want to understand better some of the mathematics, other
references are more likely to help. 

The Corums introduce, with no explaination, some equations which give the
1/4 wave resonant frequency of an unloaded helix. These equations appear
in "Reference Data for Radio Engineers - 4th ed" with more infromation on
their specific applicability for use as normal mode helical antennas. These
equations were adapted from a paper on travelling-wave tubes: "Theory of 
the Beam-type Travelling-Wave Tube" by JR Pierce in Proceeedings of the 
Institiute of Radio Engineers, vol 35, Feb 1947 p 111. ( In fact this paper 
was predated 20 years by a German paper....)

For other general information of helical resonators, check out IEEE 
Transactions on Antennas and Propegation. The tesla coil falls roughly 
under the Normal Mode (Not Axial) of operation in a helix. Most of the 
formulas derived for the resonant frequency will work for unloaded (no 
terminal capacitance) Tesla coils, but beware of any Q formulas. They will 
generally not be applicable to tesla coils since they were derived in the 
limit of much higher frequencies. One of the problems in finding useful 
formulas for Tesla Coils is that there is not much current theoretical 
interest in these systems in the professional antennas community. In the 
100-400kHz frequency range, Tesla coils make very poor radiators of radio 
waves! However, I have not yet followed up on theoretical advances in 
travelling-wave tubes....


-Ed Harris