Flat coils & undamped waves (was Wire Length)

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: "Lau, Gary" <Gary.Lau@xxxxxx>

Why is flat coil geometry significant in this or any other context?  Is
there any electrical or functional difference between using a flat
secondary and a helical secondary, beyond one being much more difficult
to fabricate?

Perhaps I'm not understanding something correctly, but my understanding
of an "undamped wave" is just a waveform that stays at a constant
amplitude, as is the voltage coming out of an AC socket, an RF
transmitter, or CW oscillator.  A "damped wave" is what you get in a
disruptive Tesla coil, where the amplitude begins at some peak value and
diminishes exponentially with time.  Aren't all of these references to
undamped waves just referring to the output of a very high frequency
mechanical CW alternator - a high frequency variant of what powers our
power grid?

Vacuum tube Tesla coils and some non-disruptive solid-state coils do
generate CW, or undamped waves, but Tesla lacked the technology to do
this using active devices.  Did he couple a mechanical high frequency
alternator into a matching resonant transformer, to boost the voltage
and produce a true CW Tesla coil?  Was resonant-rise involved?  While in
theory he had the technology to do this and could have built a CW coil,
the only coil topology he used that I'm familiar with is with disruptive
spark gap technology.  I can't figure out just what he was doing from
the text you cited.  Perhaps vagueness was his intent?

Gary Lau
MA, USA

> Original poster: "Gary Peterson" <g.peterson@xxxxxxxxxxxx>
>
> Ed, Bill, and Mike,
>
> It's good to know we are all in agreement that Tesla's 1898
> flat-spiral type transmitter is, in fact, a spread spectrum Tesla
> coil RF transmitter.  The unanswered questions are 1) is the
> transmitted energy spread out in the intervening portion of the RF
> spectrum between the upper and lower frequencies, and, if so, how
> much of the transmitters RF energy appears in this region?  2) If
> there is RF energy in the intervening portion of the band, does this
> energy contribute to the operation of the wave complex receiver?
>
> As for my comment about Tesla being able to "generate practically
> undamped waves," I was giving him benefit of the doubt in regards to
> one of his methods, which had been used, and still is, for creating
> damped waves.  A search for "undamped" in "NIKOLA TESLA ON HIS WORK
> WITH ALTERNATING CURRENTS and Their Application to Wireless
> Telegraphy, Telephony and Transmission of Power : An Extended
> Interview" produces results directly related to the 1898 flat-spiral
> transmitter.  For example,
>
>      "In the meantime, as I was developing all this, I had
> already struck a new line of effort toward producing vibra-
> tions; namely, I had developed a system permitting me
> to take the ordinary current of any main and transform it
> into any kind of vibrations I desired, either damped or
> undamped." [p. 11]

<massive snip (please see original post Subj: Re: Wire Length)>