Re: Tuning with two torids

Hi All,

	Of course, if you run a PVC tube down the center of the coil, one would
have to consider the possiblity of it drawing an arc.  You would probably
have to either build the coil large enough to overcome the field stresses
or put disks or rings along the tube (like HV power pole insulators) to
prevent arcs from tracking along the tube.

I liked the linear drive thing at the website basically because it had no
senstive electronics (unlike the ones with microprocessors :-)) and it
could be controlled with good rugged relays and such.  They showed much of
the internal contruction and there is little that can go wrong.

I thought about the laser pointer idea too but my aim is not that good and
I think it would be hard to aim with sparks and all.  A tripod may solve
this as Jeff suggests.  Adding fiber cable and the trivial switch/LED
ciruit to the other end of the cable is not that much more work, but to
each their own...  I have a rifle with laser sights and a scope that could
easily hit any target, but that type of 'laser pointer' is not "politically
correct" in most situations, although, the rifle does have a tripod
mounting nut.

At 09:38 AM 11/01/1999 -0800, you wrote:
>Terry & All,
>> > I would think the simplest way to move a top toroid up and down
>> >would be to run a plastic rod (like PVC) up the center of the
>> >primary, secondary, and first top terminal
>> Be careful doing this. I just had a spark go down the middle of my
>> secondary along a piece of pvc. It left a gouge and a burn mark all
>> the way down and then jumped to the ground connection. 
>This is a VERY common failure mode. Many builders employ
>interior baffles on their secondary coil forms to prevent
>internal flashover. Having a structure that violates the internal
>insulation of a secondary is not the way to go IMO.
>The linear drive device that Terry referenced might work
>if it is rigged so as to be self-powered, shielded and remote
>A simple up/down control can be made using photoresistors
>(yes, low tech CadSulfide) and a laser pointer. Located on the
>"toroid height adjuster" will be two targets: UP and DOWN.
>Hit either target with a laser pointer and Bob's your uncle. No
>tether (fiberoptic or otherwise) and no 5v logic. True, you'd
>have to have good aim but that's what tripods are for...
>(Here we go...TWO laser pointers mounted on a common
>tripod. Up and down controls at your fingertips...)
>Jeff Parisse