>However there are instances, for whatever reason, that a resistive material
solves the problem.<
Very definitely. There's a book now out of print called 'Radio Transmitters' by
Brown of Marconi. He has quite a lot on parasitic suppression in big
transmitters - and points out that the box can be a VHF resonant cavity (we're
talking 50 -100kW transmitters or more) and resistive loading by having such a
thing as an 80 ohm carbon resistor - Globar type, 12 inches long, 1 inch
diameter - with one end connected to the anode and the otehr in free space can
privide enough resistive loading to kill a VHF parasitic. Or even several of
them at various angles.
Rather out of our legal power levels.......
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