Last updated
WSR-1 – 4 [1]
WSR-1 radar and radiosonde dome North Omaha Airport.jpg
The upper air and radar (WSR-1) site, on the left, at the North Omaha Airport from 1954 to 1974.
Country of originUnited States
No. built82
Type Weather radar
Frequency3.3 GHz (S band)
PRF 325 and 650 Hz
Beamwidth 3.5°
Pulsewidth1 and 2μs excepted 1 and 4 μs on WSR-4
Rangemore than 100 kilometres (62 mi)
Diameter2 m
Azimuth 0 to 360º
Elevation-2 to 50º
Power50 kW

The WSR-1 or Weather Surveillance Radar-1 was one of the first weather radars and the first used by a civilian organization in the US. [2] The WSR-1 series was a modified version of the AN/APS-2F radar, which the Weather Bureau (now the National Weather Service) acquired from the Navy. The WSR-1A, WSR-3, and WSR-4 were also variants of this radar. [1] The first WSR-1 in the USA was at Washington National Airport in Washington, D.C. in 1947, [1] and the last WSR-3 was retired by 1978. [3]



In 1946, the US Weather Bureau (ancestor of the National Weather Service) retrieved 25 AN/APS-2F aeronautical radars from the US Navy. The radars have been modified and adapted to meteorology and then delivered at the rate of five per year. The modifications were conducted by the weather service and the modified radars took the successive names of WSR-1, WSR-1A, WSR-3 and WSR-4, depending on the gradual improvement of hardware. [1] The first WSR-1 was put into service at the Washington, DC, national airport on March 12, 1947. The second began service on June 1, 1947 in Wichita, Kansas, in the heart of the Tornado Alley. [1] In August of the same year, the WSR-1 installed at Norfolk, Nebraska proved its usefulness and cost savings by alerting the Elkhorn Valley power system of the approach of thunderstorms. [1]

Three particularly severe weather events occurred during the spring of 1953 and led to the establishment of the Texas Tornado Warning Network. Major cities in Texas have been asked to fund the operation (both the private and public sectors) of modifying and implementing the WSR-1, WSR-1A, WSR-3 and WSR-4. The Weather Bureau agreed to operate these radars and maintain them in order to alert the public in case of danger, as soon as a visual confirmation was obtained. The establishment of the network became effective during a kick-off meeting on June 24, 1953. [1] It took nearly six years for the network to be fully operational; 17 radars have been modified and installed thanks to the joint efforts of local authorities, the state, federal agencies and a university. [1]

The APS-2F modified by Texas A & M University, although not actually part of the tornado surveillance network, was at least once used for warning purposes on April 5, 1956. [1] After 1956 the modification of the APS-2F radars in their WSR-1, WSR-1A, WSR-3 and WSR-4 versions was assigned to the Weather Office headquarters which had to move some antennas that had originally been installed to locations where it was difficult to ensure the maintenance. [1]

In April 1975, at the peak of the program, 82 WSR-1, WSR-1A, WSR-3 and WSR-4 were in service. [1] Some were replaced by WSR-57s, but most remained in service until they were replaced by WSR-74s during a period from 1976 to 1980. [1] No more remains in service today.


Meriden, Kansas, tornado as observed by the Topeka Weather Bureau WSR-3 radar. Meriden, Kansas, tornado as observed by the Topeka Weather Bureau WSR-3 radar.jpg
Meriden, Kansas, tornado as observed by the Topeka Weather Bureau WSR-3 radar.

The WSR-1 to 4 series, the first operational weather radar in the United States, used the AN/APS-2F electronics, including a superheterodyne receiver, but with a larger antenna. As time progressed and experience with the original design increased, the Weather Bureau felt confident enough to upgrade the WSR-1 to WSR-1A, eventually finalizing on the WSR-3 and WSR-4 model. The WSR-4 upgrades included the removal of the original aircraft-oriented antenna in favor of a larger antenna, and the addition of a power converter such that it would now have the ability to function on conventional power. [1]

The main difference between the versions was their display and the control of the probed atmospheric volume. The diameter of the dish was nearly 2 meters by the WSR-4. The wavelength used was about 10 cm which corresponds to a frequency of 3 GHz. This frequency is in the S band which is still used by the current US weather radar network. Thanks to the radars operative frequency, the attenuation due to the rain was almost zero, [4] but the detection of a light rain or snow was delicate because of the weakness of the signal emitted by the radar (50 kW). [1]

WSR-3 console WSR-57 Weather Radar Console.jpg
WSR-3 console

The WSR-1 used a panoramic display (PPI) placing weather echoes in azimuth/distance coordinates on a circular screen whose center represented the position of the radar, and also a linear oscilloscope (A-Scope) showing the intensity of the echoes according to their distance from the radar. [1] Everything was mounted on a rack. The WSR-3 and WSR-4 used A-Scope displays and height/distance displays (RHI) which allows a vertical sectional view in a chosen direction. They were mounted next to each other on a console. The WSR-1A used the same displays but stacked vertically. From a technical point of view, the WSR-4 had a traveling-wave tube that improved the sensitivity compared to the WRS-3. [1]

Radar Sites

NWS office and WSR-3 radar Hunstville International Airport NWS office and WSR-3 radar Hunstville International Airport.jpg
NWS office and WSR-3 radar Hunstville International Airport

The 82 radar sites of WSR1, 1A, 3 and 4 are listed below

WSR-1 and 1A sites [3]
LocationCommissionedDecommissionedReplaced by
Baton Rouge, LAAugust 16, 19551973?
Burrwood, LA19561960WSR-4
Fort Worth, TXApril 21, 1954April 1961WSR-57
Hartford, CT19551959WSR-3
Dodge City, KSJune 13, 1954July 25, 1963WSR-3
Lubbock, TX1954August 1972WSR-74C
Norfolk, NEJuly 27, 19471976WSR-74C
North Omaha, NE19551977WSR-74C
Oklahoma City, OKMarch 1, 19551960WSR-57
Philadelphia, PANovember 20, 1959 ?
Pittsburgh, PA1952?October 4, 1963
Port Arthur, TXJuly 15, 1955 ?
St. Louis, MOJune 19551960WSR-57
Shreveport, LANovember 19551976WSR-74C
Sioux Falls, SD19561976?WSR-74C
Springfield, MOJune 28, 1957 ?
Tampa, FL19561960WSR-57
Topeka, KS19531957WSR-3
Tulsa, OKMay 4, 19561976WSR-74C
Waco, TXApril 28, 19551976WSR-74C
Washington, DCMarch 12, 1947 ?
Wichita, KSJune 1, 1947June 5, 1956WSR-3
Wichita Falls, TXApril 25, 1956
(Replaced a military APS-2F radar)
Worcester, MAMarch 16, 19561976WSR-74C
WSR-3 sites [3]
LocationCommissionedDecommissionedReplaced by
Abilene, TX25 March 197227 August 1977WSR-74C
Albany, NY12 November 195827 July 1977WSR-74C
Astoria, OR1 June 19591 November 1967
Binghamton, NY15 June 19598 March 1978WSR-74S
Chicago/Midway, IL19 April 1958January 1963WSR-57
Cleveland, OH13 May 1957WSR-74C
Columbia, MOAugust 1957November 1977WSR-74C
Columbus, OH12 February 195919 January 1977
Détroit, MI1 May 195712 September 1962WSR-57
Dodge City, KS25 July 196325 July 1972
Eureka, CA1957June 1972Given to California State University in Humboldt
Flint, MI15 November 195715 January 1978
Fort Smith, AR30 August 196029 December 1975WSR-74C
Fort Wayne, IN195712 March 1976WSR-74C
Hartford, CT29 April 1959April 1977WSR-74C
Hunstville, ALOctober 19581977WSR-74C
LocationCommissionedDecommissionedReplaced by
Indianapolis, INOctober 1959September 1977WSR-74C
Jackson, MS19591969WSR-57
Little Rock, AR19 December en remplacement d'un AN/APS-2E militaire19 April 1962WSR-57
Macon, GA21 April 195818 April 1977WSR-74C
Madison, WI29 March 195815 May 1979WSR-74C
Memphis, TN1957 ?
Meridian, MS16 August 19592 November 1976WSR-74C
Miami, FLDurant la Seconde Guerre mondiale ?
Montgomery, ALOctober 19581971WSR-74C in 1977
Muskegon, MI9 May 195725 March 1976WSR-74C
Nashville, TN2 April 195731 October 1970WSR-57
Richmond, VA7 July 1958October 1959
Rochester, MNSeptember 1960April 1976WSR-74C
Scottbluff, MOSummer 19691978
Tatoosh Island, WA1 October 1960January 1964
Topeka, KS19571976WSR-74C
Wichita, Kansas 5 June 195622 June 1960WSR-57
WSR-4 sites [3]
LocationCommissionedDecommissionedReplaced by
Burrwood, LA1960 ?
Concordia, KS1 June 196218 February 1977WSR-74C
Savannah, GA7 April 19601970

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