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Terminal Doppler Weather Radar
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Terminal Doppler Weather Radars are located near some major airports and are used to detect wind shear or microburst activity. According to MIT Lincoln Laboratory:
"A microburst is an intense localized downdraft that is sometimes generated by a thunderstorm. If an aircraft inadvertently encounters a microburst while flying at low altitude, it may lose altitude rapidly and not be able to recover in time to avoid a crash. In fact, a series of commercial aviation accidents in the 1970s and 80s led the FAA to commission a sensor capable of remotely detecting low-altitude wind shear phenomena such as the microburst. The resulting product was the Terminal Doppler Weather Radar (TDWR), which is now deployed at 45 major airports around the country."
Additional information about TDWR is available at the MIT Lincoln Laboratory Web site.
The FCC allows Unlicensed National Information Infrastructure (UNII) devices in the 5150-5350 and 5470-5825 MHz bands, which overlaps the band used for TDWR. To avoid interference to TDWR and other radars, UNII devices operating in the 5250-5350 and 5470-5725 MHz bands must automatically sense and avoid radar signals. There have been several instances of interference to TDWR from UNII devices that were either operating outside their designed bands or had dynamic frequency selection intentionally disabled.
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Frequency Bands |
| Band | Use | Service11 | Table |
| 5600 - 5650 MHz | Terminal Doppler Weather Radar | Meteorological Aids | F |
Associated Files:
A peak-hold plot (blue line) of the spectrum of the Washington Dulles TDWR at 5605 MHz.
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