WSR-74

radar Radar is a system that uses radio waves to determine the distance ('' ranging''), direction ( azimuth and elevation angles), and radial velocity of objects relative to the site. It is a radiodetermination method used to detect and track ...

s were Weather Surveillance Radars designed in 1974 for the

National Weather Service The National Weather Service (NWS) is an Government agency, agency of the Federal government of the United States, United States federal government that is tasked with providing weather forecasts, warnings of hazardous weather, and other weathe ...

. They were added to the existing network of the

WSR-57 WSR-57 radars were the primary weather surveillance radar used by the United States for over 35 years. The National Weather Service operated a network of this model radar across the country, watching for severe weather. History The WSR-57 (Wea ...

model to improve forecasts and severe weather warnings. Some have been sold to other countries like Australia, Greece, and Pakistan.

Radar properties

There are two types in the WSR-74 series, which are almost identical except for operating frequency. The WSR-74C (used for local warnings) operates in the C band, and the WSR-74S (used in the national network) operates in the

S band The S band is a designation by the Institute of Electrical and Electronics Engineers (IEEE) for a part of the microwave band of the electromagnetic spectrum covering frequencies from 2 to 4 gigahertz (GHz). Thus it crosses the conventiona ...

(like the WSR-57 and the current

WSR-88D NEXRAD or Nexrad (Next-Generation Radar) is a network of 159 high-resolution S-band Doppler weather radars operated by the National Weather Service (NWS), an agency of the National Oceanic and Atmospheric Administration (NOAA) within the United ...

). S band frequencies are better suited because they are not attenuated significantly in heavy rain while the C Band is strongly attenuated, and has a generally shorter maximum effective range. The WSR-74C uses a wavelength of 5.4 cm.Paul Sirvatka. "WSR - Weather Surveillance Radar." Radar. College of DuPage. 4 Apr. 200

It also has a dish diameter of 8 feet, and a maximum range of 579 km (313 nm) as it was used only for reflectivities (see Doppler dilemma).

History

The WSR-57 network was very spread out, with 66 radars to cover the entire country. There was little to no overlap in case one of these vacuum-tube radars went down for maintenance. The WSR-74 was introduced as a "gap filler", as well as an updated radar that, among other things, was transistor-based. In the early 1970s, Enterprise Electronics Corporation (EEC), based out of

Enterprise, Alabama Enterprise is a city in the southeastern part of Coffee County, Alabama, Coffee County and the southwestern part of Dale County, Alabama, Dale County in Southeastern Alabama, United States. Its population was 28,711 at the 2020 United States cen ...

won the contract to design, manufacture, test, and deliver the entire WSR-74 radar network (both C and S-Band versions). WSR-74C radars were generally local-use radars that didn't operate unless severe weather was expected, while WSR-74S radars were generally used to replace WSR-57 radars in the national weather surveillance network. When a network radar went down, a nearby local radar might have to supply updates like a network radar. NWS Lubbock received the first WSR-74C in August 1973 following widespread attention from the F5

Lubbock tornado During the evening hours of May 11, 1970, a very powerful multiple-vortex tornado struck a large portion of the city of Lubbock, Texas, Lubbock, located in the state of Texas, United States. The incident resulted in 26 fatalities and an esti ...

of 1970. 128 of the WSR-57 and WSR-74 model radars were spread across the country as the National Weather Service's radar network until the 1990s. They were gradually replaced by the WSR-88D model (Weather Surveillance Radar - 1988, Doppler), constituting the

NEXRAD NEXRAD or Nexrad (Next-Generation Radar) is a network of 159 high-resolution S-band pulse-Doppler radar, Doppler weather radars operated by the National Weather Service (NWS), an agency of the National Oceanic and Atmospheric Administration (NOAA) ...

network. The WSR-74 had served the NWS for two decades. The last WSR-74C used by the NWS was located in Williston, ND, before being decommissioned at the end of 2012. No WSR-74S's are in the NWS inventory today, having been replaced by the WSR-88D, but some of these radars are in commercial use.

Radar sites in the US

WSR-74 and WSR-57 weather radar network United States

WSR-74 sites include the following two categories:Stormtrack.org Forum 10344
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References

National Weather Service weather radars

Radar properties

History

Radar sites in the US

See also

References