Re: Tube Type Tesla Coils

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Hi John,
         You wrote....

> I have noticed lately that sometimes over 50% of the Tesla List postings
> refer to tube type TC's. It should be noted that tube type TC's are not true
> Tesla coils.

Actually Tesla was after a goal of high breaks and CW operation in a 
number of cases. It was difficult for him to physically realize with 
the equipment he had at the time. I'd suggest that classifying tube 
coils like this is largely semantics. 

> Tube TC's operate with continuous sine waves from a radio transmitter type
> of power supply. The load on the transmitter is not the usual resistive
> antenna type load but a reactive coil circuit load.

I beg to differ. Once loaded by spark they are loaded like an 
antenna, albeit with a non-linear resistance. VSWR is high until 
sparks are emitted, then it drops drastically and tends to stay low 
as loading is more or less continuous.
     I don't think a separate list is needed at all.

> This device uses coils
> and capacitors in a much different manner than the way they are used in
> standard Tesla coils. There is no charging of a primary capacitor to create
> dampened sine waves like the typical classical TC, etc. This type of
> operation produces brush type sparks and sometimes disruptive sparks
> depending on the adjustments.
> The tube operation and the classical coil TC (or magnifier) operation are
> two completely different methods of producing sparks. The standard classical
> TC operates with a VSWR of about 10 to 1000 while the tube TC operates with
> a VSWR of about 1 to 3 like most radio transmitters. I show a graph of these
> two types of operation in the Tesla Coil Notebook. Has anyone tried to
> measure the VSWR of their classical or tube coils? The Corum's said they had
> made these measurements but gave no details. I have tried to make these
> tests but did not have much success.
> At one time I started to add a chapter to one of my books that would cover
> tube TC's. I soon realized that I could not find enough information on these
> devices to develop a method of engineering design criteria that was possible
> with the typical classical TC's. 
> It appears that now there are several coilers that have enough information
> to write a tube TC book and publish it for other coilers interested in this
> type of device.
> My question is " Should tube TC's be on a separate Tesla List of it's own?".
> Coilers who are interested in tube types will then not have to scan thru
> classical coil (or magnifier) postings to find the information they need.
> John C. 

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