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Re: Counterpoise?
In a message dated 12/4/98 1:26:36 AM Pacific Standard Time, tesla-at-pupman-dot-com
writes:
<<
Thanks to everyone that helped with my previous really long post. :)
I ran into another question....
I have been reading the archives and there was mention of using a
counterpoise instead of an earth ground for a coil.
This is of interest to me since I am currently building this for use in
schools and such where I may not have a good RF ground set up. I will
build one for my home, but I may not be able to guarante a good one
elsewhere. The first run away from home is scheduled in late January and
it gets real cold arround here that time of year. Any sugestions? I have
asked to be located near an exit from the building to I can attempt to get
a ground.. I may be able to get access to a water pipe as well.
My first thought is to use some more flashing or screening laid out in the
snow with maybe some rock salt thrown on it to help conduct (melt the
snow a bit). Or see if I can get a decent ground from a water pipe.
Any help appreacted, driving ground rods into frozen ground doesn't sound
like fun to me.
Travis
>>
Travis,
A counterpoise is a good alternative to an earth ground for a small coil. You
did not say how much power you are running. If the supply is 12 or 15 kv at
30 or 60 ma, I would think a counterpoise would work well, especially for a
portable, indoor type coil. A couple of chunks of mesh metal screen or
fencing maybe 5 ' x 5 ' each should work well. Just lay them on the floor off
to one side or directly under the coil, connected together and to the base of
the secondary. Someone should be able to calculate just how many square feet
of conductor is required for this based on the power supply size, but I would
not know how to do it. Sounds like a good math project for someone.
Ed Sonderman