Re: Over-coupled or under-insulated?

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Paul Nicholson by way of Terry Fritz <teslalist-at-qwest-dot-net>" <paul-at-abelian.demon.co.uk>

Chris Roberts wrote:
 > the secondary is grounded ... to a sink drain pipe. The sink is
 > about 20 feet away.

While in some sense it could be said that the sink is grounded, what
really matters from the secondary coil's point of view is that it
readily catches all the E-field coming off the coil and topload.

It's likely that the sink makes a small target at that range :)

Try using a mesh groundplane directly beneath the secondary.  Forget
the sink - keep the RF contained within the direct vicinity of the
coil.   Efficiency will be higher, interference lower, and less of
a fire and safety hazard.

Without some sort of groundplane below the coil, the potential of
the secondary base with respect to its immediate surroundings
(including the primary) will not be so well defined.  Its potential
with respect to the sink is currently guaranteed, but that's not
really what you want :)

--
Paul Nicholson
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