Re: New to the group

Tesla List wrote:
> >From julian-at-kbss.bt.co.ukThu Aug  8 14:01:07 1996
> Date: Thu, 8 Aug 96 15:19:32 BST
> From: Julian Green <julian-at-kbss.bt.co.uk>
> To: tesla-at-pupman-dot-com
> Subject: New to the group
> Hello,
> I'm Julian Green and am new to this group.  I am interested in TCs
> having read all about it from Richard Quicks mail archive (rqmsgs.txt).
>  I have built my own coil and for a first attempt was very pleased
> with the results (22" streamers).
> Having read a message in my first batch of mail from this group I
> noticed that soneone was wondering why more input power does not
> increase the spark length by a similar amount.   I have a theory:
> By observing my own coil running on a variac, I have noticed that
> an increase in input power does not produce longer sparks, but more
> of them.  (The sparks do get longer but not a much as expected).
> I have put this down the the output frequency of the
> coil.   As the frequency of the coil increaces the capacitance of
> the air becomes more significant and discharge can occur at shorter
> distances.   Without a toroid the resonant frequency is even higher,
> the spark length shorter, but the cloud of crona around the top
> very much larger.
> My coil resonates at 220 KHz with 12" toroid.
> So if you want longer sparks, lower the frequency of the coil
> (add a huge toroid, or add more turns).  When you have a lower
> resonant frequency and the number of parallel sparks reduced
> increacing input power should yeild longer sparks.
> Please correct me if I am wrong.
> Julian Green.


I have left your message in tact.  It is a good post.  You are 
undoubtedly correct in all your assumptions, save one.  As you note, it 
would be very difficult to ever get long sparks out of a 1Mhz coil!  The 
air load is just too great.  The ones I have made and other systems I 
have seen all look like a natural gas burner on low!  The enery that 
doesn't go into Rf is turned almost 100% into Ozone production! All spark 
goes to loading the air capacitance, again, as you say, but the ion cloud 
probably SHRINKS instead of expands.  Shorter sparks, remember!  The ion 
cloud is actually the supporter of spark.  The high frequency coils are 
better RF emitters than spark emitters.  More of the energy can be 
readily converted in such a high frequency system to RF radiation. 

It would be incredibly interesting to see a 10KW, 1MHZ, spark excited, 
coil in action!!  Better put on your oxygen masks!

Lower frequency coils require incredibly massive metallic terminal 
loadings to suppress spark and thereby radiate a significant amount of 
their power input out as Rf energy.  Thus, they make natural spark 
emitters.  The best small coils are all below 500Khz and the best really 
big coils are all below 100Khz.

Richard Hull, TCBOR