VLF Transmitter Cutler

The VLF Transmitter Cutler is the United States Navy's very low frequency (VLF) shore radio station at Cutler, Maine. The station provides one-way communication to submarines in the Navy's Atlantic Fleet, both on the surface and submerged. It transmits with call sign NAA, at a frequency of 24 kHz and input power of up to 1.8 megawatts, and is one of the most powerful radio transmitters in the world. It was originally located in Arlington, Virginia.

The station began operations in 1913 as a radio telegraphy station call sign NAA in Arlington, Virginia, at a facility next to Fort Myer. Although its broadcasts occasionally included band concerts and speeches, it was most famous for its nightly time signals. The three towers known then as "The Three Sisters" stood 600 feet, 450 feet and 200 feet (183, 137, and 61 m) above the ground. The site was referred to as "Radio", Virginia. The towers were the second largest man-made structure in the world behind only the Eiffel Tower. The word "Radio" was first used instead of "Wireless," in the name of this Naval Communications facility. The First Trans-Atlantic voice communication was made between this station and the Eiffel Tower in 1915. The Nation set its clocks by the signal and listened for its broadcast weather reports. The Towers were dismantled in 1941 as a menace to aircraft approaching the new Washington National Airport. The towers stand today at United States Naval Academy in Maryland, on the edge of the Chesapeake Bay.

The current Cutler Naval Station was built in 1960 and became operational on January 4, 1961. It has a transmission power of 2 megawatts, and it was at one time, and perhaps still is, the most powerful radio transmitter in the world. As with all VLF stations, the transmitter has a very small bandwidth, and so cannot transmit audio (speech) but only coded text messages, at a relatively low data rate. The transmission consists of a continuously encrypted minimum-shift keying (MSK) signal capable of multi channel operations. The transmitter operates on 24.0 kHz. In the past it operated on 17.8 kHz. The callsign of the station is NAA.

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