Modulation

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

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