VLF Transmitter Cutler
Encyclopedia
United States Navy
The United States Navy is the naval warfare service branch of the United States Armed Forces and one of the seven uniformed services of the United States. The U.S. Navy is the largest in the world; its battle fleet tonnage is greater than that of the next 13 largest navies combined. The U.S...
's very low frequency
Very low frequency
225px|thumb|right|A VLF receiving antenna at [[Palmer Station]], Antarctica, operated by Stanford UniversityVery low frequency or VLF refers to radio frequencies in the range of 3 kHz to 30 kHz. Since there is not much bandwidth in this band of the radio spectrum, only the very simplest signals...
(VLF) station at Cutler
Cutler, Maine
Cutler is a town in Washington County, Maine, United States. The town was named after Joseph Cutler, an early settler. The population was 623 at the 2000 census.-Geography:...
, Maine
Maine
Maine is a state in the New England region of the northeastern United States, bordered by the Atlantic Ocean to the east and south, New Hampshire to the west, and the Canadian provinces of Quebec to the northwest and New Brunswick to the northeast. Maine is both the northernmost and easternmost...
. The station provides one-way communication to the United States strategic submarine forces
Submarines in the United States Navy
There are two major types of submarines in the United States Navy: ballistic missile submarines and attack submarines. In the U.S. Navy, all combatant submarines are nuclear-powered. Ballistic subs have a single, strategic mission: carrying nuclear submarine-launched ballistic missiles...
.
History
The station began operations in 1913 as a radio telegraphyWireless telegraphy
Wireless telegraphy is a historical term used today to apply to early radio telegraph communications techniques and practices, particularly those used during the first three decades of radio before the term radio came into use....
station in Arlington, Virginia
Virginia
The Commonwealth of Virginia , is a U.S. state on the Atlantic Coast of the Southern United States. Virginia is nicknamed the "Old Dominion" and sometimes the "Mother of Presidents" after the eight U.S. presidents born there...
, at a facility next to Fort Myer
Fort Myer
Fort Myer is a U.S. Army post adjacent to Arlington National Cemetery in Arlington County, Virginia, across the Potomac River from Washington, D.C. It is a small post by U.S...
. Although its broadcasts occasionally included band concerts and speeches, it was most famous for its nightly time signals. The current Cutler Naval Station was built in 1960 and became operational on January 4, 1961.
Transmitter
Frequency-shift keying
Frequency-shift keying is a frequency modulation scheme in which digital information is transmitted through discrete frequency changes of a carrier wave. The simplest FSK is binary FSK . BFSK uses a pair of discrete frequencies to transmit binary information. With this scheme, the "1" is called...
(F1B) signal at 200 baud
Baud
In telecommunications and electronics, baud is synonymous to symbols per second or pulses per second. It is the unit of symbol rate, also known as baud rate or modulation rate; the number of distinct symbol changes made to the transmission medium per second in a digitally modulated signal or a...
. The transmitter operates on 24.0 kHz. In the past it operated on 17.8 kHz. The callsign of the station is NAA.
Antenna
The extensive antenna system consists of two completely separate arrays, designated the “north array” and the “south array”.Each array consists of six diamond shaped panels supported by 13 towers. The system was designed to allow transmission by one array (single) or both arrays (dual). The central tower of each antenna system is 304 m (997.5 ft) tall. It is surrounded by six 266.7 m (875 ft) tall
masts, placed on a ring with a radius of 556 m around the central tower. The remaining six towers of the array are 243.5 m (799 ft) tall and placed on a circle of 935.7 m (3070 ft) around the central tower.
Each radiating element (“panel”) of the antenna is spun between the central tower, two towers of the inner ring and one tower of the outer ring.
The masts are surrounded by free-standing lattice towers. At least one of them is partially guyed.
Antenna maintenance
Antenna maintenance is performed during the summer months. During maintenance periods the station transmits on one array while people work on the other array, which is grounded. This allows continuous transmission, crucial since the Navy closed AnnapolisNSS Annapolis
NSS Annapolis, officially known as Naval Communications Station Washington, D.C. Transmitter or NavCommStaWashingtonDC, was a Very Low Frequency and High Frequency transmitter station operated by the United States Navy....
(NSS), the only other East Coast
East Coast of the United States
The East Coast of the United States, also known as the Eastern Seaboard, refers to the easternmost coastal states in the United States, which touch the Atlantic Ocean and stretch up to Canada. The term includes the U.S...
VLF station.
The region where the two arrays come close together, near the transmitter house, is called the "bow-tie area". There are two panels and three towers from each array in this area. The fields on the grounded array are highest in the bow-tie area due to proximity to the active array. The present station operating procedure, based on a past RADHAZ survey, does not allow work on the bow-tie area towers or panels while transmitting on the other array. There is an ongoing tower painting project at Cutler scheduled for completion over the next few years. Under the present station policy, completion of this project would require several months of total downtime, which is unacceptable.
Test transmissions have been arranged, during which only four panels of one array shall be connected to the transmitter. The objective of the four-panel tests was to allow painting and normal maintenance on the bow-tie area towers of an inactive array. A secondary objective of the tests is to determine the antenna operating parameters which had not been measured since changing to 24.0 kHz.
See also
- Jim Creek Naval Radio StationJim Creek Naval Radio StationJim Creek Naval Radio Station is a United States Navy facility at Jim Creek near Oso, Washington.-VLF radio facility:The primary mission of this radio site is to provide VLF radio transmitting capabilities for the Pacific submarine fleet...
- Naval Communication Station Harold E. HoltNaval Communication Station Harold E. HoltNaval Communication Station Harold E. Holt is located on the northwest coast of Australia, north of the town of Exmouth, Western Australia. The town of Exmouth was built at the same time as the communications station to provide support to the base and to house dependent families of U.S...
- Lualualei VLF transmitterLualualei VLF transmitterVLF transmitter Lualualei is a facility of the United States Navy near Lualualei, Hawaii transmitting orders to submerged submarines in the very low frequency range. VLF transmitter Lualualei, which operates under the callsign NPM on 21.4 kHz and 23.4 kHz, uses as antenna two guyed...
- List of masts