Re: [TCML] Tuning Questions

[futuret@xxxxxxx]

 Charlie,

Maybe the coupling wasn't all that tight to begin with?  It's true though
that a lower powered coil of a given size can tolerate a tighter coupling
than a higher powered coil of that same physical size (assuming
the same break rate).  Surely you'll get longer sparks if you parallel
another OBIT, but the coil may still benefit from tighter coupling,
after that.  It's difficult to say for sure in advance.  If you add another
OBIT and leave the spark gap spacing unchanged, the break rate will
increase, so the bang size may stay the same.  With an extra
OBIT, you may need a fan blowing on the spark gap for cooling
(if you're not already using a fan).  

I usually make my secondary coil adjustable in height.  First I lower
the secondary until l get racing sparks, then I raise it until they stop.

  http://futuret.110mb.com

Cheers,
John

 


 

 

-----Original Message-----
From: cbroring@xxxxxxx
To: tesla@xxxxxxxxxx
Sent: Sat, Feb 13, 2010 9:42 pm
Subject: Re: [TCML] Tuning Questions 


Matt, 
 
Thank you very much for replying to my questions. 
 
This evening I added the "off axis tuning" inductor and beefed up all the connections in the primary.   As probably everybody else knows chasing the optimum primary tuning is a bit like shooting at a moving target because the secondary tuning changes when streamers or arcs develop.  Anyway, I didn't find much improvement here. 
 
I tried a nice tidy "professional looking"  nail break out point on the top load toroid and it it doesn't work as well as the previous screwdriver hanging over the edge of the toroid. 
 
Then I had a Eureka moment.  I raised the primary 1.5 inches and the coil really woke up.  I guess it needed tighter coupling.  I need to redesign the primary and try even more coupling.  So, I have another question for those more experienced coil builders.  Is the need for close coupling a common characteristic of an under powered coil such as mine?  If I parallel a second OBIT will the extra available driving current lessen the need to tightly couple the primary and secondary? 
 
Thanks 
 
Charlie 
K3YA 
 


 
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