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Re: super cheap capacitance/inductance Tesla coil metering



Original poster: Terry Fritz <vardin@xxxxxxxxxxxxxxxxxxxxxxx>

Hi Dmitry,

I am not sure exactly what you are trying to measure or what signals you are looking for. If say 1MHz will work for you, then frequency modulation and all should be fine. I think LEDs go to like 150MHz now. I have wondered about using a laser diode or super bright LED too.

In my case, I was concerned about all the 25MHz stuff where modulation and all would be difficult. It is fairly simple with high speed analog LEDs to transmit directly anyway. 95% of all the good stuff is below 2MHz so that should be fine.

You could also perhaps use radio. A very low powered wide bandwidth transmitter and receiver might be interesting.

Cheers,

        Terry


At 07:54 AM 12/14/2005, you wrote:
> Original poster: Terry Fritz <vardin@xxxxxxxxxxxxxxxxxxxxxxx>

>> > Hi Dmitry,
>>
>> > The current to the streamer tends to be made of high frequencies
>> > along with the streamer's fundamental frequency current.  So you need
>> > to measure with a high bandwidth like 2Mhz to "see" much.
>>
>>how much frequency deviation shall i use to transmit such signal
>>undistorted?

> About 4X the fundamental frequency for air streamers for the basic
> signals.  There is some stuff up to about 25MHz.  Here are scope
> pictures of Greg's big Electrum coil:

i see from the waveforms, that "stuff up to about 25MHz" has miserable
amplitude, most "stuff" is in rage to about 5MHz max, so like you said
earlier "bandwidth like 2MHz" is probably all that i really need.
"4X the fundamental frequency" is only about 260Khz for my coil, so
what`s the problem that you see with frequency modulation of this
signal? even if you assume Fmax=2MHz - what`s the problem you see, but
constantly failing to explain here?
even if you take the modulation index m=5 as in stereo broadcasting,
this only means carrier frequency about 10-12MHz, and Fmax would be
about 22MHZ max - what`s the problem again?

as i see here:

http://hot-streamer.com/TeslaCoils/Misc/Project_color.pdf

your LEDs was happy with "40+ MHz" - so why my LEDs should be unhappy
with only 22MHz?

-----
I have never heard of a coiler blowing up a pole pig!  A pole pig can
easily blow up a coiler, however.  You could also be hit by a bus though.
27-08-96 (c) Richard Hull, TCBOR