22 Jun
2004
22 Jun
'04
6:40 a.m.
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).
I don't work in the field (no pun ...) so I have no idea
how soon it will be before new TV (and radio) transmitters
are built using semis. I just assume that the existing ones
won't be replaced any time soon (since they presumably work)
and that the natural replacement rate is relatively low.
I could be wrong about either of these things. I've not
heard that the new digital services require new transmitters
(just new ways of generating signals I guess) and it could be
that we all move to cable/satellite services and ditch
terrestrial anyway. I just don't think it will happen.
Semiconductors have advantages in many areas (power, speed,
robustness) but it may be that these do not apply (or do
not apply so much) in the high power, high frequency arena.
I do expect the main vacuum tube in most display devices will
be gone within the next ten years or so. I would have thought
the tubes at the middle of the chain (the final stages of
the transmitter) would be mostly still around by then.
Antonio
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Antonio Carlini arcarlini(a)iee.org