Re: 3/4 wavelength secondaries

Tesla List wrote:
> >From sgreiner-at-wwnet-dot-comThu Jul 18 22:44:31 1996
> Date: Thu, 18 Jul 1996 16:29:39 -0700
> From: Skip Greiner <sgreiner-at-wwnet-dot-com>
> To: tesla list <tesla-at-pupman-dot-com>
> Subject: 3/4 wavelength secondaries
> Hi everyone
> I wonder if anyone has ever tried to wind a secondary at 3/4 wavelength
> rather than 1/4 wavelength.
> It appears that it may not be possibe to wind a 1/4 wavelength coil that
> will resonate at the correct frequency without using the large terminal
> capacitance. Perhaps a 3/4 wave coil could be made.
> I would appreciate any comments.
> Skip


Absoluetly!  It'll work... for a little while.  You see, at the 1/4 wave 
point, 1/3 the way up the coil, you would get an arc flashing across the 
windings. (Resonant rise)  At 2/3 the way up, you could put you hand on 
the coil.  (1/2 wave point- zero volts)  Then at the top you would have 
the same voltage as at the 1/3 point (another 1/4 wave node).

Actually all coils (any coil) are 1/4 wave, 1/2 wave, 3/4 wave and full 
wave!!!!  (for some specific frequency!)

This is why a mistuned or grossly over-coupled coil arcs up and down its 
length!  Various other frequencies are also present and find their 
natural resonant rise points (1/4 wave points)along the coil and arc 

You don't need a toroid to make a coil oscillate at its natural 1/4 point 
you only need to dump in a quantity of magnetic or directly coupled 
energy at its natural frequency.

No coil will ever oscillate at the quarter wave point predicted by the 
wire length equation.  (due to inductance and self capacitance.)

Richard Hull, TCBOR