22 Jun
2004
22 Jun
'04
6:20 a.m.
AFAIK they are. I remember reading an article in (I
think)
one of the IEE rags some time ago that described some new
generation of semiconductors that could handle the combination
of power and frequency, but they were only being used in
specialised applications because of the cost. I assume that
your average TV transmitter mast will stay with valves for
a while yet.
Don't bet on tubes being used in broadcast use for long - the
semiconductor has made serious inroads into the field (as in 50 kW). Same
with radar (although tubes probably have more life in radar than in radio
or TV).
William Donzelli
aw288(a)osfn.org