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Re: Solid-state TC - transformer design



>   Has anyone tried using a counterpoise ground instead of grounding the
>opposite side of the output transformer(the end not connected the base
>of the secondary) to earth ground? I have Duane A. Bylunds book and
>there is a section on counterpoise grounds.
>   I would like to use this method instead so I can operate the coil
>indoors. His book leaves a few questions unanswered. Like can the
>opposite side of the output transformer be connected to ONLY the
>counterpoise?

No

The counterpoise will reduce the currents in the earth wire by up to
50% according to Duane. But if you have no connection to earth ground
then your counter poise / coil system will be at an extremely high
voltage compared to the electronics - like 200 kV accross the output
transformer - ZAP!  The counterpoise is floating but it is still connnected
by capacitance to ground. 
If you then connect the electronics also to the counterpoise
the voltages will then appear accross the mains transformer - ZAP :)

I've got away with using the electrical ground but then I've lots of earthed
metal pipes going underground.

Ground connection is essential but a counterpoise will reduce the ground
currents. A pair of electronic magnifiers driven out of phase would also 
significantly reduce the earth currents. 

The only system that I can see possibly working without a ground
connection is the "Oudin" type coil. A long horizontal seconday coil with a
toriod on each end, driven by a conventional primary around the middle.
Or of course a coil operating inside a large metal box :)
The best counterpoise suggested for your appartment was of course
the battleship Missouri but this totally ignored the practical dificulty of 
drillinga hole in steel armour deck plate for the earth connection ;)

Counterpoises are on a my long to do list of experiments. I missed out
on picking up some really cheap copper clad board at a recent ham fest.
I could have etched a fine tree like structure on it - retaining 90% of the 
copper, all electricaly connected but no paths for eddy currents. And
arranged them in an umberella shape around the coil base.

Have fun,

Alan Sharp (UK)