In article , philo wrote:
On 03/27/2016 11:49 PM, Hank wrote:

I've always felt that deForest's history was another exercise in
alchemical strangeness. It seems fairly clear that he did not have any
real understanding of why or how his tubes worked, or what they might be
capable of actually doing. Nor did he ever devise any practical
circuitry for using them. A much larger contributor to circuitry was
Armstrong, whose patents were overturned in favor of deForest later
on---generally regarded as a travesty of justice. Development of the
high-vacuum triode with a scientific understanding of what the control
grid was doing to the electron stream---and development of a concomitant
technology for series production of the devices was more an AT&T/Bell
Labs effort. Also, the first major use of these devices was as
telephony repeater amplifiers.

Hank




And of course superheterodyne and FM...he really knew what he was doing.

Armstrong was a major contributor---but whether he actually "invented"
the superhet seems to be in doubt, as there was considerable French work
in frequency conversion during WWI. No question that Armstrong brought
the superhet to the home entertainment market with the RCA Radiolas of
the early 1920's. These were really strange beasts, as they used a
reflex circuit to reduce tube count. Add to that the "catacombs"
construction---a wax-filled can with V99 tube sockets. I had one of
these (a "portable") from 1924 as a teenager, and really went through
fits to get it to work, after melting all the wax out of the catacomb.
That portable had a "loudspeaker" (a headhone-type driver into a horn)
and an extra v99 to drive it.

Armstrong's FM was really his baby. All the theoreticians said it
wouldn't work, but it did. I once worked with an old-timer who'd been
involved in setting up the original NTSC TV standard in 1941. They
purposely put a hook into RCA's condemnation of FM by specifying FM for
TV audio (said he).

Hank

Hank