On 03/30/2016 09:35 PM, Hank wrote:



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).




Thanks for the info, I did not know that.