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Measure that frequency shift. (or, at least, change the subject) :-) (fwd)



---------- Forwarded message ----------
Date: Sat, 18 Jul 1998 17:04:50 -0600
From: terryf-at-verinet-dot-com
To: Tesla List <tesla-at-pupman-dot-com>
Subject: Measure that frequency shift.  (or, at least, change the  subject) :-)

John, Richard, and All
 
It is easy to measure all the frequencies or time intervals you want (ring
up, none breakout, streamers, etc).  It takes two items or their
equivalents.  Any good 50 ohm antenna with a 50 ohm load (to prevent ringing
between the scope and the antenna's impedance) and a digital storage scope.
If you have a steady signal perhaps a non-storage scope could be used with
skill. 

My plane antennas and a Tek 210 scope can measure all this with ease.  The
210 can measure the time intervals or instantaneous frequencies for you.

Apparently, with big streamers, we need to tune to a slightly lower (~5%)
frequency for best transfer.  The arcs seem to consist of a resistance in
the megaohm region and a roughly 5 pF of parallel streamer capacitance which
is switched in after the output voltage reaches its peak (at least that's
what this afternoon's model suggests.)  Richard points out that it is more
complicated, but on average, the models do predict real behavior fairly
well.  Antonio suggests we should tune the coupling to certain sweet spots
to help quenching also.  I think this is somewhat important but in practice
very difficult to control.  And there is the thought that the ring up may
occur before breakout and the original frequencies may be correct.  Then
there is the transformer effect.  We are getting to the point of splitting
hairs.... Which is good!

When it comes to big streamers, I find myself in the same dilemma as Tesla
did in New York.  I can't push big streamers without burning the place down.
Perhaps I need to find a lab in Colorado Springs to do my work? :-))

Of course, Tesla didn't have a computer, digital scopes, and a nice cushy
armchair :-))



Happy, in his armchair, in the basement, with his beer, in Colorado's 100+
summer temperatures.

        Terry Fritz 





At 01:45 PM 7/18/98 -0600, you wrote:
>
>
>---------- Forwarded message ----------
>Date: Sat, 18 Jul 1998 06:03:08 +0000
>From: "John H. Couture" <couturejh-at-worldnet.att-dot-net>
>To: Tesla List <tesla-at-pupman-dot-com>
>Subject: Re: How to rise the secondary? (fwd)
>
>
>  Richard -
>
>  How did you measure the frequency with and without streamers. Do you have
>any data on frequencies and streamer capacitances?  
>
>  John Couture
>
>---------------------------------------------------
>
>At 09:51 AM 7/17/98 -0600, you wrote:
>>
>>
>>---------- Forwarded message ----------
>>Date: Fri, 17 Jul 1998 01:56:41 -0400
>>From: Richard Hull <rhull-at-richmond.infi-dot-net>
>>To: Tesla List <tesla-at-pupman-dot-com>
>>Subject: Re: How to rise the secondary? (fwd)
>>
>~~~~~~~~~~~~~~~~~~~~  big snip
>
>>Rob is absolutely correct here and I have just such tests shown on one or
>two of our
>>old video report tapes.  A piece of #24 wire 6 feet long attached to a
>resonator will
>>really swing resonance on down the scale!  An flaming white hot arc is a
>much larger
>>ionic surface conductor than such a piece of wire.  Again, the old hands-on
>folks have
>>"been there....done that".  One need not be a rocket scientist to figure
>this out real
>>quick if observant around bigger running systems.
>>
>>Richard Hull, TCBOR
>>
>>
>>
>
>