Ауа-райы радарлары WSR-74 және олардың қолданылуы

Weather surveillance radar

WSR 74 radars were Weather Surveillance Radars designed in 1974 for the National Weather Service. They were added to the existing network of the WSR 57 model to improve forecasts and severe weather warnings. Some have been sold to other countries like Australia, Greece, and Pakistan.

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 (like the WSR 57 and the current WSR 88D). 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. 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).

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 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 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 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 No WSR 74S's are in the NWS inventory today, having been replaced by the WSR 88D, but some of these radars are in commercial use.