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Re: How to tune? (fwd)
---------- 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)
>>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
>>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
>>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 it.
>>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
>>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
>>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 on
>>>how to set up and properly tune your coil and it was great! now it's lost
>>>:( If anyone knows where I can find this or a similar step by step guide
>>>to setting up my coil I would be obliged. I think it might have been on
>>>gary lashus' (can't really remember his name) page but I really can't find
>>>it. All I remember is the first page on his site was him sitting on some
>>>thanks a million