On Wed, 2 Dec 2015, whit3rd wrote:

On Tuesday, December 1, 2015 at 5:23:03 PM UTC-8, Michael Black wrote:
On Tue, 1 Dec 2015, Ian Field wrote:


Apparently there was a time that most remote garage door openers had a
Nuvistor of some description.

I've never heard of that, but it's possible. There were those subminiature
tubes (the leads were generally laid out in parallel with each other, and
the leads were relatively low gauge wire) seen in hearing aids and some
portable radios.

I've heard those called 'pencil tubes'; the ones in hybrid walkie-talkies
(for the transmitter) didn't get replaced with semiconductors until mid-to-late
seventies.
I dont' think anything much new got released after a certain point. But
those tubes did offer the chance to make equipment smaller, and certainly
in the early days of transistors, the tubes had better high frequency
response. I had one of those hybrid lunch box walkie talkies, never used
it, and if I recall properly the transmitter was all tube, the receiver
had a diode mixer (no rf stage ahead of it) and a tube oscillator and
multiplier chain, with the transistors in the IF strip and audio.

But by the end of the sixties, you could get Motorola handie talkies like
the HT-200, which were all solid state. Hearing aids must have made the
transition to transistors by then, and you could get portable radios that
used transistors.


Nuvistors were ceramic-metal base, metal envelope tubes, very rugged,
and much less microphonic than other vacuum tubes. There was a long
period when they were the best fast-slewing amplifiers around, and for
HV handling (like electrostatic deflection in CRTs) very hard to replace
with silicon.

But at the time, top end test equipment wasn't as well known to the
hobbyist. It was only later that I learned the Tek 454? (the mostly solid
state one, not the one from 1959 with the plugins) used nuvistors.

Michael