WWI Era U.S. Navy Receivers

Last update:  31 July 2020.

lot of this material was extracted from:
History of Communications-Electronics in the United States Navy
Captain L. S. Howeth, USN (Retired)
Available at: https://archive.org/details/historyofcommuni00howe


Radio communications attracted the interest of the Navy, for obvious reasons, very early on.  For the moment, I'm going to ignore everything before about 1909 when crystal detectors replace coherers, magnetic detectors, etc.

In the beginning receivers were just coherer detectors connected directly to the antenna-ground system.  There was no tuning except for the resonance of the antenna system.

Oliver Lodge assisted Marconi in the development of the syntonic (tuned) system covered by the  "Four Sevens" patent.

Lodge's receiver  incorporated two tuned circuits.  The "open circuit" achieves a conjugated match to the antenna, allowing maximum energy transfer.  The "closed circuit" adds additional selectivity and matching to the detector

This would become the standard architecture for most communications receivers of the wireless era.

The response of cascades tuned circuits adds algebraically.

IP 76

  • Double-Tuned Crystal Set
  • Pickard Mineral Detectors
  • Widely used 1909-1914

The Continuous-Wave Revolution



Th DeForest  "Ultraudion" circuit, inspired by Armstrong's regenerative patent provided a means of heterodyne detection for CW reception.  Various external audion control boxes would be used until the development of the SE-1420 receiver.

Much of the following development work was carried on at the Washington (DC) Navy Yard.  This facility was responsible for receivers, detectors, amplifiers, frequency-meters, and transformers.

Navy Type A, B, and C Receivers
Origin of the tickler coil in regenerative receivers

Dr. Louis Cohen who, while associated with the National Electric Signaling Co., had worked with Dr. Austin in the formulation of the Austin-Cohen empirical formula, had devised a new means of coupling, utilizing condensers in lieu of the induction coils used by Marconi. The Navy obtained the right to the use of the Cohen patents, and procured his temporary services to assist in the design of receivers.'

Howeth, Chapter XVII, p213-214

The Navy was attempting to stay clear of some of the existing regenarative patents. "The Cohen method was used. This consisted of coupling and a modified type of feedback circuit, with a coil in the plate circuit for the purpose of making the vacuum tube oscillate. To avoid the use of the term "feed-back," Clark termed it "a 'tickler' because it tickles the audion and makes it quiver."

Even though the tickler feedback circuit is often called the Armstrong oscillator, it does not appear in Armstrong's patents in this exact form.

  • Double-Tuned Crystal Set
  • Cohen Circuit
  • Connections for external "Audion" for regenerative operation, allowing reception of continuous-wave (CW) signals.
  • Design completed in early 1915, and placed in production at the Washington Navy Yard in the same year
  • Frequency Range:
    • Type "A" (60-600 kc.)
    • Type "B" (30-300 kc)
    • Type "C" (1,200-3,000 kc.)
  • Type A, only 40 produced.
  • Type B, never reached production.

SE-95 and SE-143 (IP-500)

Excellent pix here: http://online.sfsu.edu/hl/IP500.html

  • Early 1916 redesign of Type A and B receivers
  • SE-95 (CN-239 is similar)
    • 30-300 kcs
  • SE-143 (CN-208 is similar)
    • 100-1,200 kcs
    • Navy's WWI utility set.

Development of SE 143  Howeth, Chapter XX
"Receiving Equipment" p 254

SE 143 Manual

Personal tie-in:  I work at The Radio Technology Museum  located at the former Marconi Belmar Station, and we have some of this equipment on display.


  • Interim design, late 1918
  • Frequency range:  45-1000 kcs
  • First Navy design to use inductive coupling
  • Quickly superceeded by SE-1420
SE 1220 Manual

Untuned secondary provides a "standby" function for quick, broad tuning.

SE-1420 (IP-501)

  • Sophisticated design by L.A. Hazeltine of Neutrodyne fame, but, contrary to some sources, it does not incorporate a Neutrodyne circuit.
  • First Navy receiver with the vacuum tube inside.
  • Frequency range 40-1275 kcs
  • Became the standard navy receiver for many years.
  • Some interesting VIDEOS of the set in action.
  • Also see:  http://www.radioblvd.com/ip501.htm
SE 1420 Manual

SE 143 Manual

SE 1220 Manual

SE 1420 Manual

IP 501A Manual

Also, take a look at Nick Englands "
Navy Pre-war SE (Steam Engineering) Receivers"

Communications Receivers

Skywaves Homepage