# Re: [TCML] Show and tell first SGTC

```Thanks to you guys that have checked out my post & photos.... Gary, Brian, Matthew, and Deano. I appreciate it.  Brian you are absolutely right! It's very exhilarating to have success after all the planning and construction of this project.

Question-  On my 15 turn primary coil, I'm tapped to the maximum of the length of the coil. Would it be worth a try to remove some turns from my secondary coil (de-tune?) to achieve a better output. Assuming this would hopefully achieve a closer match in resonance....
I have shortened the secondary coil from 23" to 20" now and haven't observed a noticeable difference, but it seems that most of the other coilers have their primary tapped somewhere closer towards the middle. The end just seems to be the best place to tap. I just don't want to keep shortening my secondary if it's not changing much.
Thanks again!

Here is some video of some of my first runs.... Hope u enjoy

https://youtu.be/W04DvEe8c5k

https://youtu.be/ke4lWN4o2xY
Sent from my iPhone

> On Aug 28, 2016, at 7:35 PM, Brian Hall <brianh4242@xxxxxxxxxxx> wrote:
>
> This brings up a general question I have, given what I've read here over the years on this list vs. what I have learned about LC resonance in a recent college circuit theory class.
>
> If the resonant frequency F = 1/(2pi(sqrt(LC))) then why does the capacitance of the primary circuit need to be matched to the transformer?
>
>
> Or is it that the primary capacitor has two attributes: voltage and capacitance.  The capacitor voltage needs to handle what the transformer voltage can deliver, (or 1.5 to 2x the transformer max out volts)  and the primary coil L and primary capacitance C need inductive and capacitivie values such that F = 1/(2pi(sqrt(LC)))   holds true, and match with the same resonant frequency F of the secondary LC circuit?    Is that all we need to change when we swap out a transformer in the primary circuit, just the voltage max on the capacitor?
>
> And Adam, yes I too would like to see a link to the video of your coil, always fun to demonstrate your first one!  So satisfying to see those sparks fly.
> ----------------------------------
> Brian Hall
>
>
>
> ________________________________
> From: Tesla <tesla-bounces@xxxxxxxxxx> on behalf of Jonathan Peakall <jpeakall@xxxxxxxxxxxx>
> Sent: Sunday, August 28, 2016 11:15 AM
> To: Tesla Coil Mailing List
> Subject: Re: [TCML] Show and tell first SGTC
>
> Adam, Not too surprising that you saw little improvement. The extra
> voltage isn't as helpful as more current would be. Try getting a match
> to any of the transformers you have and run them in parallel. You need
> to phase the outputs, plenty of info about that out there. Then of
> course you will need to change your tank cap value.
>
> Hope you have a safety gap set low enough that it dings your
> performance. And if you don't have a Terry filter I would recommend
> making one. NST's are pretty easy to fry.
>
> Jonathan
>
>
>> My name is Adam. I'm elated to be a new member. I was really captivated by the Tesla Coil by the you tube community and researching Nikola Tesla sparked my interest even more.
>> Around the beginning of 2016 I decided to try and build my own spark gap tesla coil. Before summer in May; I finally had success!!
>> Powered by a Transco 12,000 volt 30 mA NST into a homemade terry filter minus the MOVs. A tungsten rod static gap quenched with a vacuum pump and ceramic magnets. A homemade MMC; one string on Cornell Dubilier 942....-K connected in series. Primary coil is 1/4" soft copper tubing starting 5 & 1/2" inner diameter in a conical rise of 15-20 degrees approximately.... 50' of copper 15 turns tapped at the very end of the inner and outer turns. My secondary is a 4" PVC pipe 22" tall and the windings take 20" of the pipe. I used 28 AWG magnet wire and for a toroid I used the housing out of a ceiling fan which I sanded free of paint. It's about 14" in diameter and about 2 & 1/2" tall. It works well, but gets a lot of streamers due to the edge facing the bottom.
>>      I've recently swapped to a 15,000 volt 30 mA NST. France brand. Also added 3 more caps to my MMC for a new total of 18 in series. It has improved slightly from the 12kV NST, but only slightly. I will soon have another 15kV 30 mA NST; Transco brand. I anticipate a big improvement in output.... Anyway, just wanted to share with the community and ask for anybody willing to share thoughts/tips/advice etc... Any constructive criticism is welcome and I appreciate all feedback. Trust that I will take it in with an open mind. Here are some pics and video... Hope u enjoy:
>>
>>
>>
>>
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