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30MHz Spark Gap Testing - Is this real??
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From: D.C. Cox [SMTP:DR.RESONANCE-at-next-wave-dot-net]
Sent: Tuesday, April 07, 1998 12:09 PM
To: Tesla List
Subject: Re: 30MHz Spark Gap Testing - Is this real??
to: Terry
Your work is very clever and quite timely. I would urge you to consider
forwarding a copy to Harry Goldman for publication in a future edition of
TCBA News. We have always used a xmfr / SG parallel configuration with the
cap in series downstream. This seems to provide optimum life for NST and
potential xmfrs when operated as a power source for Tesla oscillators. If
you test setup is still active you might repeat your experiments adding the
secondary coil and setting its discharge path to a short 3-4 inches. It
would be interesting to see what effect this extra "load" has on the data.
Please keep us on the list posted.
DR.RESONANCE-at-next-wave-dot-net
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> From: Tesla List <tesla-at-pupman-dot-com>
> To: 'Tesla List' <tesla-at-pupman-dot-com>
> Subject: 30MHz Spark Gap Testing - Is this real??
> Date: Monday, April 06, 1998 8:02 AM
>
>
> ----------
> From: terryf-at-verinet-dot-com [SMTP:terryf-at-verinet-dot-com]
> Sent: Sunday, April 05, 1998 11:44 PM
> To: Tesla List
> Subject: 30MHz Spark Gap Testing - Is this real??
>
> Hi All,
> I believe that I have made a new and significant discovery regarding
spark
> gap operation. My experiments, which deal with the measurements of
voltages
> and currents in the primary circuit, have shown that the operation of the
> spark gap is not that of a simple switch.
> It is generally believed that when the voltage across the spark gap
reaches
> a certain level that current passes through the gap and super heats the
air
> creating a virtual short across the gap. This short remains in place
until
> the primary circuit losses energy and the super heated air region can no
> longer be maintained. At this point, the resistance is believed to rise
and
> the gap "quenches" and the resistance returns to a very high level.
Typical
> measurements performed with relatively low bandwidth equipment more or
less
> have demonstrated this phenomena. Once the gap has closed, the current
> through the gap is assumed to be a simple decaying sine wave.
> When equipment capable of much higher bandwidth is employed this picture
> seems to change dramatically. When one terminates a quality antenna into
> the proper 50 ohm impedance the fundamental signal seems overwhelmed by
> heavy noise spikes. This explains why a simple wire is often used as a
> scope probe to receive primary waveforms as opposed to a higher quality
> antenna system. The simple wire and its very poor impedance matching to
the
> input of an oscilloscope attenuate these noise signals so that only a
nice
> clean signal is left.
> If one uses a high bandwidth properly terminated antenna, a series of
noise
> spikes are seen (my testing was done without the secondary inductor in
> place). Careful examination will show these spikes appear as a series of
> noise bursts that occur at the peaks of the fundamental frequency. The
> power of these noise bursts is vastly higher than the fundamental
waveform.
> In my testing, I have found that these burst consist of ~50MHz signal
bursts
> that persist for about 100nS and then fall off to a much lower level.
The
> power of these bursts is remarkable. Early testing has shown that, even
at
> low voltage levels, these bursts may reach many hundreds of amps at the
> ~50MHz frequency. By far the most powerful burst is the very first one.
> Typical scope photos often show this as a vertical line that occurs just
at
> the beginning of conduction. My equipment has not been able to measure
the
> level of this spike with great accuracy but it appears to be around 400
amps
> which is remarkable considering the relatively low 2000 volt spark gap
> setting. What is even more remarkable is that the current outside this
> burst appears to be close to zero. In other words the full current in
the
> primary seems to be conducted only in these short bursts.
> Others and I have measured nice sine wave currents in the primary system
> before. So how can the preceding be true? I fear we have been tricked
by
> the low frequency response of the equipment we used and the classical
> impulse response of those systems. These energy bursts can easily act as
> pure impulses which will excite a low bandwidth system producing sine
waves.
> We may have only been seeing the heavily damped response of these current
> bursts.
> What are the implications if this is true? If the primary circuit is
doing
> all of its work at ~50MHz and at hundreds, if not thousands, of amps at
that
> frequency, everything changes! The conductors must be short, wide,
copper
> strips. The capacitors must be able to withstand even greater stresses
than
> we ever imagined. And the spark gaps... who knows? This would imply
that a
> much better spark gap or other switching system may give much better
> performance. EMI becomes a major concern. At 200KHz it is easy to
> disregard EMI. At 50MHz all kinds of problems can arise.
> I have written a paper on all this. It is available in Word 97 format
and
> as an HTML web document at:
>
> http://www.peakpeak-dot-com/~terryf/tesla/experiments/experiments.html
>
> Look at the 30MHz Primary Circuit Measurements section. You may want to
> save the graphics and view them with a viewer to get the highest
resolution.
> The main page is:
>
> http://www.peakpeak-dot-com/~terryf/tesla/main.html
>
> I realize this is a rather dramatic change in the way we all look at
> primary circuits. I have tried my best to confirm this. Unfortunately,
I
> seem to be rather alone in my ability to probe into these regions so
> independent confirmation is difficult. However, I am confident that the
> truth will be determined quickly. As far as I can tell everything
appears
> to be working properly and all the results I have seen make sense and
appear
> very real.
>
> Thanks
>
> Comments are very welcome.
>
> terryf-at-peakpeak-dot-com
> or
> terryf-at-verinet-dot-com
>
>
> Terry
>