Re: 1/4 wave theory

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

Original poster: "Jim Lux by way of Terry Fritz <twftesla-at-qwest-dot-net>" <jimlux-at-earthlink-dot-net>

>
> >> > Is it advantageous to design a coil such that the linear feet of
> >>>wire in the secondary is equal to 1/4 of the operating wavelength?
>
> >         Simple answer is NO!
>
> Tend to concur.
> But.
> I suggest that is only half the question.
> The other half is:
>
> Should the secondary resonate as an electrical
> 1/4 wave?

Easy to predict numerically, given sufficient time and computer resources...

However, given that most tc secondaries have this big old capacitor on the
end (topload), there is no particular reason to expect that the
current/voltage distribution would look like that on a resonant wire.

I think that Terry has made measurements showing about 30 degrees of phase
shift from top to bottom of a typical coil*, and, of course, there are actual
numerical models from Paul and others showing the voltage distribution.

What would be difficult is coming up with an analytical model (i.e. an
equation, as opposed to a simulation).


*I saw practically zero phase shift.
http://hot-streamer-dot-com/TeslaCoils/MyPapers/topsync/topsync.html
 - terry


>
> (Note that THIS is a separate question.  And exceeding hard
> to predict numerically, as it depends among other things,
> on the aspect ration (length/dia) of the coil. ).
>