Re: Tesla's Radio Circuit (was tuning more accurately than 5%) (fwd)

---------- Forwarded message ----------
Date: Fri, 24 Jul 1998 11:06:55 -0600
From: "D.C. Cox" <DR.RESONANCE-at-next-wave-dot-net>
To: Tesla List <tesla-at-pupman-dot-com>
Subject: Re: Tesla's Radio Circuit (was tuning more accurately than 5%) (fwd)

to: John, List

I think Tesla did at first start with the induction coil.  He had recently
developed the high frequency alternator capable of 10,000 cycles per
second, and it would be only logical that he would grab an antique
induction coil to see the effects of the higher frequency currents at high
potentials.  He probably first noted that the high frequency currents, due
to their capacitive coupling natures, quickly broke down the insulation and
destroyed the induction coil.  He then probably tried different types of
insulations to solve these problems and somewhere along the line discovered
that he could completely remove the iron core from the coil and it would
still work.  Tesla was quite aware of the fact that higher frequencies
required less iron because he had a long standing dispute with Westinghouse
engineers over which standard would be more efficient vs. less costly with
regard to 50 Hz vs. 60 Hz currents in motors and distribution transformer
systems. He would realize that as the frequency increased less and less
iron would be necessary for an efficient transfer of energy from primary to
secondary inductors in an induction coil.  As he used larger and larger
induction coils in his experiments and used less or no iron in their cores
to obtain higher and higher potentials a point would be reached wherein the
actual mechanical case work of the induction coil would present a target
for the high secondary potentials.  Remove the case, turn the assembly 90
degrees to vertical, and now you have a system that has no targets --- no
internal iron core to arc to, no multiple layer secondary windings to arc
to, and no enclosing case to arc to.  It would seem to me that this
progression is quite logical and would most certainly start with the
materials immediately on hand as the high frequency alternator experiments
progressed --- the nearby standard laboratory induction coil would be a
quick first choice.  In published experiments conducted by Tesla before the
IEEE there are several photos and sketches that show Tesla using a high
frequency alternator driving a standard induction coil with an iron core.  

Later, another interesting progression of the evolution of the Tesla coil
also takes place.  Tesla noted the standard cylinder shape of the secondary
coil presented capacitance problems with arcing and corona off the last
turn.  He then developed the pyramid shaped coil which eliminated this
problem.  This pyramid then shrinks downward to become a completely flat
spiral coil (Archemedian spiral).  Oher experimenters, notably David Sloan
in the 1930's, placed the coil into a tank, and with its large capacitive
effects, became a coaxial resonator and transmission line system that
operated at 150 kilowatts to produce over 1,000,000 volts at 100 kilowatts
output.  This system was used to drive high power x-ray tubes for cancer

> From: Tesla List <tesla-at-pupman-dot-com>
> To: tesla-at-pupman-dot-com
> Subject: Re: Tesla's Radio Circuit (was tuning more accurately than 5%)
> Date: Thursday, July 23, 1998 9:50 PM
> ---------- Forwarded message ----------
> Date: Thu, 23 Jul 1998 05:13:18 +0000
> From: "John H. Couture" <couturejh-at-worldnet.att-dot-net>
> To: Tesla List <tesla-at-pupman-dot-com>
> Subject: Re: Tesla's Radio Circuit (was tuning more accurately than 5%)
>   Richard, All -
>   I disagree about Tesla having "honed what was first just a glorified
> induction coil system". The induction coil and the Tesla coil are two
> completely different electrical concepts.
>   The induction coil stores electricity in a coil and produces a high
> voltage (inductive kick) when the circuit is OPENED. The Tesla coil
> electricity in a capacitor and produces a high voltage (in the secondary)
> when the circuit is CLOSED. There is much more.
>   However, this is not the important radio aspect of the Tesla coil that
> Marconi stole from Tesla. Up until the time of Tesla's "Tesla coil"
> invention it was impossible to transmit more than microwatts using
> circuits and radio waves. Tesla's invention was a dual RCL circuit that
> it possible to go from microwatts to megawatts in radio transmitters.
> is the concept that Marconi stole from Tesla. The US patent department
> conned by Marconi into believing Marconi's circuit was a different
> Even today the radio concept of Tesla's invention is not well known or
> understood.
>     John Couture
> -----------------------------------------------------
> At 09:33 PM 7/21/98 -0600, you wrote:
> >
> >
> >---------- Forwarded message ----------
> >Date: Tue, 21 Jul 1998 00:58:30 -0400
> >From: Richard Hull <rhull-at-richmond.infi-dot-net>
> >To: Tesla List <tesla-at-pupman-dot-com>
> >Subject: Re: tuning more accurately than 5% (fwd)
> >
> >
> >
> >Tesla List wrote:
> >
> >> ---------- Forwarded message ----------
> >> Date: Sat, 18 Jul 1998 23:20:06 -0700 (PDT)
> >> From: Michael Nolley <mhnolley-at-willamette.edu>
> >> To: Tesla List <tesla-at-pupman-dot-com>
> >> Cc: tesla-at-pupman-dot-com
> >> Subject: Re: tuning more accurately than 5% (fwd)
> >
> >
> >
> >>  how did Tesla himself
> >> conceive of the Tesla coil first, theory or experimentation?  There
> >> accounts of him recieving a "vision" about the operation of the AC
> >> in Prague in 1896-- was Tesla primarily a theoretical or an
> >> genius?  I don't know much about his handbooks/ journals etc.  Perhaps
> >> one of you could enlighten me.
> >>                         --Mike
> >
> >  There is no single recorded lightbulb event for the Tesla coil.
> Certainly not
> >like the much repeated rotating magnetic field illumination.  Tesla
> into
> >the thought of the tesla coil sometime between 1890 and 1892.  Probably
> >noting and studing the writings and work of Kelvin and Lodge.  He honed
> what was
> >at first just a glorified induction coil system into the air core system
over a
> >period of time.  He never published much of anything and it is only
through the
> >efforts of Thomas Commerford Martin, that any thing exists of the period
> between
> >the induction motor and his showing up with working air core Tesla coils
> >1893-1894.
> >
> >Richard Hull
> >
> >