Yes but he presumably meant dab and FM, presumably the latter as the
modulation type on digital is more complex and a lot more powerful due to
the duty cycle.
After all you are just sending a movable blank carrier on fm, more or less.
I think they probably my use travelling wave tubes at uhf though not sure
about the dab as that is band 3.
With regard to Long wave, there are whole transmitters around I think that
could be used at those low frequencies, but its true, the more specialist
the valve, the less likely it is to be available against when everyone was
using them. I'd imagine the low end of Medium wave type transmitters use
similar devices but the current Long wave transmitter is much higher power
than most of the medium wave outlets.


Brian

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"Chris Green" wrote in message
...
Chris Holmes wrote:

One for Brian???

I was wondering back when men were men and Libby Purves worked on the
other
side of the mic, radio transmitters used valves.

Are there now solid state devices (big MOSFETs??) capable of producing
the
necessary output power? Or are valves still used?

There are big semiconductor devices capable.

However old transmitters are expensive to convert to new devices. I
seem to remember that the Radio 4 transmitter on 198kHz is still a
valve and that they only have one more spare.

--
Chris Green
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