August 1931 Radio-Craft
[Table of Contents]
Wax nostalgic about and learn from the history of early electronics.
See articles from Radio-Craft,
published 1929 - 1953. All copyrights are hereby acknowledged.
Stenode tubes were a big deal
in the early 1930s, and were deemed capable of changing fundamentally the way high
selectivity receivers and transmitter preamplifiers would be designed. History had
other plans for RF circuit design. Note that both advertisements include the signature
of Stenode tube inventor Dr. James Robinson. The Stenode's success was dependent
upon being able to design a receiver circuit with the ability to "recreate" sidebands
from the carrier. That presents a dilemma mathematically since the information in
an ideal AM scheme is contained entirely in its sidebands. If the sidebands are
removed, that information is lost forever unless it is present somewhere else, like
on the carrier itself, which means pure amplitude modulation is not occurring. It
is commonplace to recover a suppressed carrier from the sideband(s), but recovering
the sidebands from a pure sinewave carrier is impossible. See articles
Stenode's Selectivity Revolutionary and
Stenode Radiostat System.
Stenode Corporation of America Advertisements
Stenode Corp. of America Ad on Page 109
Stenode Corp. of America Ad on Page 113
Posted August 7, 2023
(updated from original post on 11/18/2015)