Re: Modulation

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Sundog by way of Terry Fritz <twftesla-at-qwest-dot-net>" <sundog-at-timeship-dot-net>

Hi Malcom!

Not a mathmetician (more of a simpleton!), to audio modulate a SGTC, you
simply need a triggered gap (Marc M. setup).  Put a *tiny* tank cap on you
coil, 1nf or so, charge it with DC to eliminate resonant problems,  and
trigger the IGN coil's driver with an audio signal.  I can't foresee
excellent audio response from it, as you'd be modulating the breakrate.  But
even half-decent response, triggered with a microphone, would be impressive.
If anything, it'd let me irritate the neighbors by playing the budweiser
"Wazzap!" yell via the TC.  They think I'm weird to begin with, so I might
as well reinforce the image!
Anywho!

Shad
----- Original Message -----
From: Tesla list <tesla-at-pupman-dot-com>
To: <tesla-at-pupman-dot-com>
Sent: Tuesday, July 17, 2001 7:19 PM
Subject: Modulation


> Original poster: "Malcolm Watts by way of Terry Fritz
<twftesla-at-qwest-dot-net>" <m.j.watts-at-massey.ac.nz>
>
> Hi all,
>          I've had this crazy idea kicking around for several years
> and done nothing about it so I thought I'd put it to the list before
> someone else did. It was sparked (npi) by my thinking about the
> sideband issue which I replied to the other day.
>
>      The nub of the idea is to audio modulate a sparkgap coil. Sounds
> crazy, right? (NY parlance ;)  Thinking about it resulted in this
> train of thought: we know that the coupling constant and resonant
> frequency of the coil sets the sideband frequencies. We also know
> that k is a pure function of geometry. That suggests that the only
> way to alter the sideband frequencies (by proxy the modulation
> frequency) is to alter k, in other words, mechanically alter the
> proximity/positioning of the secondary relative to the primary. That
> amounts to moving the secondary with some kind of voicecoil
> arrangement (possibly using turns on the secondary itself as the
> motor winding).
>      BUT, if there was some other way k could be altered that didn't
> involve moving one of the coils, the goal could be met. If it could
> be done, one would want air streamers only from the secondary to
> largely preserve the loaded Q of the system. Sort of a giant ion
> speaker. Inserting a third coil coupled to the pri-sec with its
> loading electronically controlled might do the trick although that
> would alter Ksys which wouldn't be terribly desirable. Question -
> does such an arrangement alter K or does it just alter M?
>
>      Any ideas from the mathematicians on the list?
>
> Malcolm
>
>
>
>