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 . History . The station began operations in 1913 as a radio telegraphy station 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 current Cutler Naval Station was built in 1960 and became operational on January 4 , 1961 . Transmitter . Cutler Naval Station has a transmission power of 1800 kW , 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 very slow data rate . The transmission consists of a continuous encrypted FSK ( F1B ) signal at 200 baud . 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 separate identical arrays , designated the “ north array ” and the “ south array ” . Each array consists of a ring of 13 tall metal masts connected at the top by a network of horizontal cables . The cables form six diamond - shaped " panels " radiating from the central tower in a hexagonal pattern shaped like a snowflake . The two arrays normally operate together as one antenna , but each is designed to function independently to allow maintenance on the other array . 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 element ( “ panel ” ) of the antenna is suspended between the central tower , two towers of the inner ring and one tower of the outer ring . The entire array is 6140 ft ( 1 . 871 km or 1 . 16 miles ) in diameter . This type of antenna array is called a trideco or umbrella antenna . It functions as a capacitively top - loaded electrically short monopole antenna . The vertical steel masts of the antenna radiate the VLF radio waves , while the suspended cable array functions as a large capacitor , increasing the efficiency of the vertical radiators , At the base of each mast is a star - shaped network of cables suspended a few feet above the ground , extending out hundreds of feet , called a " counterpoise " , which serves as the bottom plate of the " capacitor " . The climate in Maine results in severe icing of the antenna wires during the winter , resulting in unacceptably large loads on the supporting structures . Therefore the antennas have a deicing system which runs large 60 Hz electric currents through the wires , heating them , to melt the ice . The power required for deicing is 3 MW , higher than the transmitter output power . An antenna array cannot transmit while it is being deiced , and one reason for having two arrays was to allow one array to be deiced while the other provides crucial uninterrupted transmission capability . Repairs and adjustments to an array can also be made without interrupting transmission . 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 Annapolis ( NSS ) , the only other East Coast 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 .