Original poster: Mddeming@xxxxxxx
In a message dated 10/9/06 1:27:38 P.M. Eastern Daylight Time,
tesla@xxxxxxxxxx writes:
Original poster: John <guipenguin@xxxxxxxxx>
If I cant drive a grounding rod for RF ground, what is this counter
pose under the coil I hear people mention?
Thanks,
John.
Hi John,
A counterpoise is a type of "virtual ground". consisting of
foil, wire mesh (chicken wire etc.) or radial wires arranged in a
daisy wheel at least as long and broad as the coil is high or the
topload diameter, whichever is greater. This is placed underneath
the unit with RF ground end of secondary attached to it. The
topload "sees this as ground and all works. A foil one is cheapest
and easiest, but wastes somewhat more power in eddy currents.
Radial wires are the most efficient, but hardest to do and keep
straight. a large square or circle of wire mesh is a good
compromise. NOTE: During operation, the counterpoise is floating at
unknown high potential with respect to earth ground. DO NOT TOUCH!!!!!