On the night of 30 January 1914, Edwin Howard Armstrong, accompanied by Professor Morecroft from Columbia University, demonstrated his regenerative receiver to David Sarnoff and Roy Weagant of The American Marconi Company at the Belmar receiving station then under construction.
|Marconi Operations Building and antenna masts from the Shark River side.||Op's building under construction in 1913-14. The Armstrong demo is believed to have occured in the construction shack visible here. The building still stands, but is in need of restoration.|
2014 marks the 101st anniversary of this historic event. The Marconi site morphed several time over the years, becoming the U.S. Army's secret radar laboratory in 1941, and is now the home of the InfoAge Science History Learning Center and the New Jersey Antique Radio Club’s Radio Technology Museum.
|OK, we don't know what the original regenerative receiver looked like when Armstrong made the initial discovery, but we're going to guess.|
|Armstrong's receiver was compared to the American Marconi Type 101, a sophisticated crystals set, and probably one of the best receivers then in use.|
|The IP-501 was the U.S. Navy's first receiver with the vacuum tube inside the cabinet. This regenerative design was the work of Alan Hazeltine. We'll use this as a standin for the 101.|
From David Sarnoff's report to his superiors:
Dear Sir: - February 2nd, 1914.
On January 30th I met Mr. Armstrong , Professor Morecroft
and Mr. Wiegant, with whom I proceeded to our high power station at
Belmar, N. J. to test Mr. Armstrong's receiving system.
Two aerials were erected, one about 1600 ft. long and the
other the entire length of the masts erected at Belmar.
Signals were heard from Clifden at about 4:00 p.m. (New
York time) and from this time until we finished experimenting, which
was about 5:00 A.M/. (New York time ) January 31st, no appreciable
variation of the intensity of Clifden signals was noticeable .....
Armstrong's receiver was compared with our standard 101
navy type tuner together with the cerusite and carborundum detectors.
Speaking relatively of received signals means of course, very little
since the human ear is not to be depended up on, but an idea of the
difference may be obtained when it is stated that signals from
Clifden on Armstrong's receiver could be read with ease with telephones
on the table when signals on our receiver were barely readable
with the telephones on the ears......
The Armstrong receiver proved its greatest value when used
in conjunction with continuous waves.
Signals from the Poulsen Station at Frisco, which I understand
is about 35 K.W'. having an approximate overall efficiency of
25% thus radiating from the antenna about 9 K.W. we rereceived at
Belmar at about 8:00 p.m. (New York time). The received signals
from Frisco were about 100% stronger than the loudest signals received
At about midnight ( New York time ) I heard "HU" - Poulsen
Station at Honolulu - trying to work with the Poulsen Station at
Signals received from Honolulu were sufficiently strong
to be read with the telephones on the table.....
In conclusion I would state that the results obtained
with Mr. Armstrong's receiver are sufficiently convincing to
warrant our most careful investigation of his patents and circuits,
etc., for I believe that his device has tremendous advantages, and
unless there be other systems of equal merits which are unknown
to me, I am of the opinion that he has the most remarkable
receiving system in existence.
Yours very truly,
Join us Feburary 8th or 9th to celebrate this historic event.