Radio Direction Finding

Background

After reading "Secret Weapon" by Kathleen Broome Williams (ISBN: 1-55750-935-2) about shipboard High Frequency Direction Finding (HFDF) and it's impact on sinking German U-boats I wanted to have a look at the patents relating to direction finding.

There are different flavors of Radio Direction Finding (RDF). In navigation systems the transmitter is at a known frequency and transmits pretty much all the time. But in the case of a distress transmission the frequency is known (was 500 kHz) but the duration is short. And in the case of a German sub in W.W. II the frequency is sort of known and the transmission time is very short (under one second).

Model Numbers

SE950

1918 Navy aircraft LW direction finder

Patents

984108 Apparatus for Determining the Direction of Space Telegraph signals, Oscar C. Roos, Feb 14 1911, [Secret Weapon pg 76] 342/439

System using two whip antennas along the centerline of a ship

1590346 Radio Direction Finding, L.M. Clement (WE), Jun 29 1926,

Bellini-Tosi principle

1606476 Radio Signaling System, J.O. Mauborgne & G. Hill, Nov 9 1926,

Includes loop antenna on with azimuth and elevation adjustments

1717674 Aerial System for Wireless Signaling, C.S. Franklin (RCA), Jun 18 1929

Combines two crossed loop antennas seperated by a wavelength and adds a sense antenna

2083495 Electrical Indicating or Measuring System, H.S. Black, E&J Edison, (Bell Labs),Jun 8, 1937 [Secret Weapon pg 81, 251]

CRT indication of relative phase or amplitude of two same frequency singals
2423437 Direction Finder, H.T. Budenbom (Bell Labs), filled: Aug 25, 1934, issued: Jul 8 1947, 342/369
Short Wave DF receiver with CRT readout of difference between signals (not bearing)

2208209 Radio Direction Finder, Henri Gaston Busignies (Intl Std Elec Corp), Filed: Dec 17, 1937, Issued: Jly 16 1940, [Secret Weapon pg 81, 251] 342/428 ; 324/121R; 348/116

Rotating CRT gives beraring to SW transmitter

2314029 SELF-ORIENTING RADIO DIRECTION FINDER, Donald S. Bond, W.L. Carson (RCA), Mar 16 1943,
2360810 SELF-ORIENTING RADIO DIRECTION FINDER, Donald S. Bond, W.L. Carson (RCA), Mar 16 1943,
2234331 Ultra High Frequency Radio Direction Finding, D.S. Bond (RCA), Mar 11 1941, [Secret Weapon pg 82, 251]

Vertical half wave dipoles, drives a L -center-R meter output

2454768 Direction FInding Antenna System, G.S. Burrroughs (Fed Tel & Radio Corp), Nov 30 1948

""H" Adcock type system with sense antenna
Calls:
2174016
2182950
2234331

2468064 Radiogoniometer, R. Hardy (Intl Std Ele Corp), Apr 26 1949, 342/429 ; 342/431; 342/436; 342/440

Neon lamps for Left or Right, manualy turned antenna array. "H" Addock with sense ant

2365347 Radio Direction Finding System, W.P. Lear (Lear Avia Inc), Dec 19 1944,

Manually or motor turned loop, sense antenna, for aircraft LF and MF.
Ref:
2317922
2308521

My Related Web Pages

PRD-1 Army HF Direction Finding Reveiver
AN/ARN-89 & other Aircraft Direction Finders

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