# 1/4 Wave Theories - Trash Them!

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From:  Barton B. Anderson [SMTP:mopar-at-uswest-dot-net]
Sent:  Saturday, May 30, 1998 2:30 PM
To:  Tesla List
Subject:  Re: 1/4 Wave Theories - Trash Them!

Terry and All,
I'm not sold. I know I may get blasted on this, and I hope so if it will increase my
understanding. But my biggest problem is the definition of the measurements of current
at the bottom and top of the secondary. In my understanding, in any series *resonant*
LC circuit, the phase angle is always 0 degrees regardless of the length of the
winding, be it a 1/4 wave, 1/2 wave, or everything in between of the *inducing*
circuit. This is due to the *net* reactance of L and C cancelling, leaving only Re
(effective resistance), and current across a resistive circuit has *no* phase
variation. It seems from your measurements that you have proven this. But how does this
disprove a 1/4 wave effect?

Maybe, the defition of a 1/4 wave effect is what is mis-represented. All a 1/4 wave
effect says to me is that an ac signal has a wavelength (true?) and the ac signal is
generated from the primary tank circuit of L and C ringing following the current pulse
at the sparkgap (true?). ok, every ac signal has high's and low's. The first peak is
max voltage (true?) and this max voltage will produce max current across R (true?). ok,
the secondary coil has a wavelength (true?) and if that wavelength is equal to 1/2 the
wavelength of the inducing tank, then max voltage should be expected in the center of
the coil (true?). Then also a 1/4 wavelength applied secondary should have an expected
max voltage at one end (true?). Then if max voltage is at one end, there *must be* a
smaller voltage at the other end (true?) If we multiply the current x voltage at the
*smaller* voltage end of the secondary, we end up with a x number of watts. We all
know, power will not increase (for the same time frame) in any system. Then if we take
x number of watts and divide it by the voltage at the *high* voltage end of the
secondary, we have less current (true?).

With that said, comparing *phase* of current at the base and top of a coil with a net
reactance of 0, will *not* produce a phase variation. It should however, indicate a
resonant rise of voltage and current. When I look at the waveforms you captured, I see
a smaller current at the top than at the base of the coil. Exactly as it should be. Now
if you measure voltages instead of currents (if it were possible), you would see the
base at a smaller potential than the top (true?).

Conclusion:
Compare a 1/2 wave secondary current measurement to a 1/4 wave secondary. In both
circuits tuned to resonance, the net reactance should be 0 producing max current
limited only to Re and the Q of the coil. However, I'll bet you will see a decrease in
current (top to base comparison) on the 1/4 wave secondary and no current decrease on
the 1/2 wave secondary (again, top to bottom comparison). Move the top probe to measure
middle of the coil, and then you will see the current decrease on the 1/2 wave coil.

I realize that c-top changes the distributed capacity of the secondary, and given that
most coils these days run with a large c-top, the 1/4 wave design *may not* be
advantageous for maximum voltage, but I just don't see how these waveforms are telling
me that the 1/4 wave theory's are trash? In other words, why are you looking for a
phase variation? Did you expect to see one?

BTW Terry, I enjoy your page, postings, and work with TC's *very much!!!* This
particular posting I am having trouble understanding how, "what you are measuring has
anything to do with what you are saying".

Any and All comments *very* welcome,
Bart

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