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Re: How to tune? (fwd)
---------- Forwarded message ----------
Date: Sun, 1 Jul 2007 14:06:35 -0500
From: Drake Schutt <drake89@xxxxxxxxx>
To: Tesla list <tesla@xxxxxxxxxx>
Subject: Re: How to tune? (fwd)
Thanks a lot guys! That's the site I was looking for and I also got some
other good advice from Bart and Dr. R. Although- I don't really think I can
afford a signal generator or O-scope at the moment.
On 7/1/07, Tesla list <tesla@xxxxxxxxxx> wrote:
> ---------- Forwarded message ----------
> Date: Sat, 30 Jun 2007 23:19:48 -0700
> From: Barton B. Anderson <bartb@xxxxxxxxxxxxxxxx>
> To: Tesla list <tesla@xxxxxxxxxx>
> Subject: Re: How to tune? (fwd)
> Well, silly me! Your right. I remembered the photo, but for some reason
> associated Terry. Sorry Gary and Terry (if he's still listening). Ok,
> how can I talk my way out of the this one, um, both names have two
> Tesla list wrote:
> >---------- Forwarded message ----------
> >Date: Sun, 1 Jul 2007 07:26:06 -0600 (MDT)
> >From: Chip Atkinson <chip@xxxxxxxxxx>
> >To: Tesla list <tesla@xxxxxxxxxx>
> >Subject: Re: How to tune? (fwd)
> >I think that's Gary Lau. It's his web site and says "yours truly". That
> >and it doesn't look like Terry either. :-)
> >This is the website I'm talking about:
> >On Sun, 1 Jul 2007, Tesla list wrote:
> >>---------- Forwarded message ----------
> >>Date: Sat, 30 Jun 2007 22:47:26 -0700
> >>From: Barton B. Anderson <bartb@xxxxxxxxxxxxxxxx>
> >>To: Tesla list <tesla@xxxxxxxxxx>
> >>Subject: Re: How to tune? (fwd)
> >>Hello Drake,
> >>The guy sitting in the statue of Tesla at Niagara Falls is our
> >>illustrious ex-moderator, the famous Terry Fritz! You also gave a
> >>half-name (Gary Lashus?), I can only imagine is intended to read Gary
> >>Lau. It's very possible Gary or Terry had a document with a step by step
> >>tuning procedure, but I can't seem to find it.
> >>With that said, there are various methods. There is of program
> >>prediction where you insert your coil dimensions and out pops the
> >>primary tune tap position for your coil.
> >>There are also tuning via measurement of signals and trial and error
> >>(which is actually quite good).
> >>Here is a method noted by Antonio Carlos M. de Queiroz:
> >>The method that I use is:
> >>Connect a 1 Ohm resistor across the output of the signal generator, to
> >>have a low-impedance signal.
> >>Connect the signal generator where the spark gap would be, with a
> >>low-frequency (1-10 kHz) square wave of maximum amplitude.
> >>The secondary coil and top load shall be in place. Ground can be at the
> >>oscilloscope ground.
> >>Look at the voltage over the primary capacitor, or over the primary
> >>inductor, at the transitions of the square wave.
> >>Tune the system until you see full notches, like in this photo:
> >>This is the ideal tuning without breakout. To account for streamer load,
> >>connect a wire to the top load with the length of a reasonable streamer
> >>and tune
> >>in the same way. Mark the two positions found. The best point will be
> >>somewhere between these.
> >>Note that the waveform shows also the resonance frequency of the two
> >>tanks, and allows the measurement of the coupling coefficient.
> >>You can also tune by trial and error. This typically indicates that you
> >>tap a bare wire primary at various positions along the winding of the
> >>primary which changes it's inductance and thus, the fundamental
> >>frequency of the primary coil to math the fundamental frequency of the
> >>secondary resonator. When this procedure is used (the trial and error
> >>procedure), the cap is usually a fixed value and only the primary is
> >>varied (because it is mechanically the easiest variable).
> >>There are a couple setup procedures which help this process. First,
> >>place a breakout point on your topload so that you can identify leader
> >>length visually (your tuning for the longest leader). You also should
> >>run the coil at about half power. There are two easy ways to do this:
> >>1) Using a variac, adjust the variac to 1/2 power.
> >>2) Use 1/2 the number of gaps in the static gap setup to lower the
> >>voltage to about 1/2.
> >>As you tap the primary winding (if your other parameters are now way off
> >>base), you'll find the longest spark lengths near the optimal tap
> >>position. Some coils (small L primarys) are more finicky than others
> >>(large L primarys). You'll find out how finicky your coil is by tuning
> >>So, lets say you've tuned to the long spark length. Now you need to
> >>observe the coil running. If your getting any arcs along the secondary
> >>or from primary to secondary, there are problems. If primary to
> >>secondary, you'll need to increase the proximity between coils. If
> >>racing arcs, you'll need to raise the secondary (or lower the primary)
> >>to again increase the proximity in that particular direction of the two
> >>If it's running fine without those pesky problems, you may want to lower
> >>the secondary down into the primary until you "see" those problems
> >>occur, and then raise the secondary to just get outside the racing
> >>sparks. Once you've done that, your tuned for low power.
> >>Yes, I said "low" power. Now you'll need give the coil all it's got
> >>without limiting the power. You may find that the coil is having racing
> >>arcs at high power. So, definitely go through the tuning process one
> >>more time regardless. The low power tuning helps us in the long run. If
> >>something is connected wrong, or whatever, it may prevent the coil from
> >>serious damage.
> >>Longer sparks often load the coil causing a frequency shift during
> >>normal running and likely the primary will require a little added
> >>inductance to offset the frequency shift. This can be often times termed
> >>as running "high on inductance" a few percent (maybe 5% to 8%, sometimes
> >>more if the primary coil is several turns). What this means is that from
> >>a "calculated" standpoint without spark loading, the coil runs better
> >>when it is detuned high on inductance to offset streamer loading. You
> >>might be surprised at the number of coilers that actually run high on Lp
> >>(and some without realizing it). But, many do realize this. I was very
> >>surprised to find out during some TSSP testing that everyone else
> >>testing was also tuning the coil high on inductance for "best coil
> >>output" and "a nice running coil". I'm not even sure if they all
> >>realized it. It was eye opening to me. Following this realization, I
> >>threw into Javatc a detuned output in the primary table to identify if
> >>the coil is high or low on inductance and how much via a percentage.
> >>Not sure if any of this will help. Hopefully someone will post the page
> >>you lost.
> >>Take care,
> >>Tesla list wrote:
> >>>---------- Forwarded message ----------
> >>>Date: Fri, 29 Jun 2007 22:03:22 -0500
> >>>From: Drake Schutt <drake89@xxxxxxxxx>
> >>>To: Tesla list <tesla@xxxxxxxxxx>
> >>>Subject: How to tune?
> >>>Hey everyone- I'm getting to the point where my coil is almost done and
> >>>realized that I lost a very important webpage link. It was a tutorial
> >>>how to set up and properly tune your coil and it was great! now it's
> >>>:( If anyone knows where I can find this or a similar step by step
> >>>to setting up my coil I would be obliged. I think it might have been
> >>>gary lashus' (can't really remember his name) page but I really can't
> >>>it. All I remember is the first page on his site was him sitting on
> >>>huge statue.
> >>>thanks a million