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Re: Optimal Quenching Tests
In a message dated 97-01-13 01:00:26 EST, you write:
<< >Subject: Re: Optimal Quenching Tests
>
>"2) Did the old spark transmitter engineers really say that 1st notch
quench
>eliminated splitting, or did they say it eliminated beating? Maybe they
just
>looked at their secondary waveform and said, " look, a nice clean
>ringdown....no beats....just what we want!" Also, in Richard Hull's
>comments on the subject, was he refering to splitting, or to beating? Are
>we differing on our definitions of terms?
>" >>
> John Freau
>
Bert H,
I just spoke to Lou Balint who has completed some tests for 1st notch
quenching, using a spectrum analyzer. Bert, let me say that the news fully
supports your viewpoint. I was surprised, but glad, since it means that the
threat of racing sparks should be minimized--which is something we can all
rejoice about. Now we just need the gap that can do the job.
In Lou's first test, he used a loose coupling of k = .102, he obtained what
appeared to be a monochromatic output when "quenching" (actually he used a
transistor to simulate a spark gap) at anywhere from 12 uS to 70 uS. Center
freq. was 114 kHz.
The next two tests at a higher k value are intriguing. First a k value of
.573 was used, and he obtained a double humped spectrum when using long
quench times such as 10 uS, 25 uS, 50 uS, 100 uS , etc. As the quench time
was gradually reduced, the side frequencies weakened, and the center
frequency strengthened. By the way, the optimal quench time for this set up
was 5 uS. At 5 uS quench ONLY the center frequency was seen. It was not
until around 8 uS that the side frequencies began to appear. As the quench
time was increased, the side frequencies got stronger, and the center
frequency weakened. The center frequency in this set up was 92 kHz, when I
speak to Lou again, I'll ask him for the measured side frequency values.
Lou did a third test at k = .843, the center frequency was 64 kHz, and the
optimal quench time 1.2 uS. Again, the side frequencies appeared as the
quench times got longer in a similar manner to the above test.
The side frequencies seemed to gradually become stronger as the quench time
lengthened, this supports all of our observations that racing sparks
gradually increase as quenching gradually fails.
It is good to hear of actual real-world test results in this matter. Thanks
Lou for your speedy efforts in the matter. And thanks Bert for all your
info and for being persistent in the matter, and your PSPICE data seems
vindicated. And thanks to the other list members who commented on this
matter.
I was getting set up to do some spectrum analyzer tests, but I am being
delayed by an analyzer that is either insensitive, or faulty. I will however
continue to attempt to reproduce these happy results.
A good day in Tesla Land,
John Freau