"nick" wrote in message
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If a (let's say 12v) relay is rated for 10 amps @ 110 volts,
it will take 1100 watts. Will it take 1000 watts of RF?

I would think not, but I don't know why.

There are two parameters specified, but you are reducing them to one. The
first is the current, the second is the voltage. With a non-reactive 50-ohm
load, the rf current at 1000 watts is about 4.5 amps, and the rf voltage is
70.7 V. These formulae are in every edition of the ARRL Handbook. See also
the Handbook discussion of skin effect. At higher frequencies, ac tends to
travel near the surface of a conductor. If the relay contacts are silver
plated, this may not be a problem. The contacts in the old Dow-Key coax
relays weren't very large; it doesn't take a fat relay to switch
non-reactive 50-ohm loads. If you want to switch high-impedance or badly
mismatched antennas, you may exceed the capability of the relay. Another
consideration is whether you will actually be hot-switching the rf. If the
contacts are closed before rf is applied, there is less likelihood of arcing
and damaging the contacts.

Relays designed for rf use are mechanically constructed to minimize
impedance variation through the contacts, to maintain the non-reactive
50-ohm impedance of the system. At HF, a slight impedance 'bump' is not a
big deal. For amateur HF use, this relay will probably do the job.

"PM"