Armstrong Days at Infoage  
8-9 February 2014

Last Update 7 February 2014
We're on for this weeked!  Check here if there's any doubt due to weather.

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 Belmar, nj marconi Operations Building Belmar' NJ
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.

The New Jersey Antique Radio Club’s Radio Technology Museum will host an observance of the occasion at the InfoAge Science History Learning Center and Museum in Wall Township, NJ on February 8th and 9th  from 1 to 5 PM.  There will be a display and demonstration of vintage regenerative radio receivers with a formal presentation at 3 PM.  The other InfoAge museums will be open as well.  Admission is free.  A five-dollar donation to InfoAge is suggested.

GOOGLE MAPS  Street view gives you a look of the site as it is today.

Marconi Hotel

                                          InfoAge HQ in the Marconi Hotel

Working receivers on display will include a mock-up of Armstrong’s original circuit receiving a simulated spark radio-telegraph transmission and a WWI era naval receiver.  This receiver, a Wireless Speciality Apparatus Compant IP-501, can be operated both as a crystal set (passive receiver) similar to the Marconi 101 and as an Armstrong regenerative set using a vacuum tube to provide amplification, and will give us the feel for the receivers involved in the 1914 demostration.

Armstrong is arguably the greatest radio inventor since Marconi.  His regenerative receiver was followed in 1918 by the superheterodyne, the basis for nearly all modern radio receivers. During the 1930’s Armstrong developed high-fidelity FM broadcasting.  His FM technologies also found their way into two-way mobile radio, and radar during WWII.

"Audion" Control Box 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.
IP-501 Receiver 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

from Clifden.....   


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,

D. Sarnoff

Chief Inspector

Join us Feburary 8th or 9th to celebrate this historic event.

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