Re: tuning primary and harmonics

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

Original poster: "Rob Judd by way of Terry Fritz <teslalist-at-qwest-dot-net>" <canska-at-a5-dot-com>

I would like to know the answer to your question as well!

I've observed the same thing on my coil, there seem to be several spots on
my primary that result in a large signal on the scope. And each spot is
actually a rather large range where there does not seem to be any
perceptible difference in the output. These ranges are typically about half
to 3/4 of a turn. From the info I've seen online I always thought the tuning
point would be a very narrow range, not half a turn or more. Anyhow, I've
run the coil from each of these ranges and the output is always about the
same.

I know only one of these spots is actually the true resonant point, and the
rest are harmonics, but I've never figured out how to identify (with the
scope, not by calculation) which is the correct spot. In theory, the signal
should be weaker at the harmonics than at the correct tap point?

Rob Judd - canska-at-a5-dot-com



 > >As I tuned the primary by moving the tap around, I found the amplitude
 > >on the scope rising and falling at different tap points.  I guessed
 > >these were harmonic frequencies?
 > >
 > >Anyway, I found a tap point that made the highest single on the cro and
 > >used than.  It was at 9.5 turns.  The coil works fine with this.
 > >
 > >When I later keyed in the figures into WinTesla, it reported the tap
 > >point as being just over 11 turns.
 > >
 > >I didn't try this far out when tuning the primary, so I am wondering if
 > >I had just found another harmonic at 9.5 turns.
 > >
 > >Are there a lot of places around the primary that will create a large
 > >signal on the scope?  Has anyone else found multiple tap points that
 > >make a coil work ok?