NSS Annapolis, officially known as Naval Communications Station Washington, D.C. Transmitter or NavCommStaWashingtonDC(T), was a Very Low Frequency (

VLF Very low frequency or VLF is the ITU designation for radio frequencies (RF) in the range of 3–30 kHz, corresponding to wavelengths from 100 to 10 km, respectively. The band is also known as the myriameter band or myriameter wave ...

) and

High Frequency High frequency (HF) is the ITU designation for the band of radio waves with frequency between 3 and 30 megahertz (MHz). It is also known as the decameter band or decameter wave as its wavelengths range from one to ten decameters (ten to one ...

(HF) transmitter station operated by the

United States Navy The United States Navy (USN) is the naval warfare, maritime military branch, service branch of the United States Department of Defense. It is the world's most powerful navy with the largest Displacement (ship), displacement, at 4.5 millio ...

. It was located at Greenbury Point, in

Anne Arundel County Anne Arundel County (; ), also notated as AA or A.A. County, is located in the U.S. state of Maryland. As of the 2020 United States census, its population was 588,261, an increase of just under 10% since 2010. Its county seat is Annapolis, wh ...

, across the Severn River from

Annapolis Annapolis ( ) is the capital of the U.S. state of Maryland. It is the county seat of Anne Arundel County and its only incorporated city. Situated on the Chesapeake Bay at the mouth of the Severn River, south of Baltimore and about east o ...

Maryland Maryland ( ) is a U.S. state, state in the Mid-Atlantic (United States), Mid-Atlantic region of the United States. It borders the states of Virginia to its south, West Virginia to its west, Pennsylvania to its north, and Delaware to its east ...

at coordinates . NSS Annapolis was used by the USN for

submarine A submarine (often shortened to sub) is a watercraft capable of independent operation underwater. (It differs from a submersible, which has more limited underwater capability.) The term "submarine" is also sometimes used historically or infor ...

communication. The station consisted of an

umbrella antenna An umbrella antenna is a capacitively top-loaded wire monopole antenna, consisting in most cases of a mast fed at the ground end, to which a number of radial wires are connected at the top, sloping downwards. One side of the feedline supplying po ...

supported by a 1,200-foot (365.76 m) high central mast, which was insulated against ground, 6 guyed masts of 800-foot (243.84 m) all of which were built in 1969 and three 600-foot freestanding towers built earlier. Originally the station consisted of nine 600-foot-tall self-supporting lattice towers, the tallest of their kind built in the United States to that date. The first four of which were built in 1918, followed by two more in 1922 and the final three in 1938. As of 2020, only the three built in 1938 remaining standing. The huge towers were a local landmark, and served as a visual reporting point for aircraft landing at the nearby Baltimore-Washington International (BWI) airport. A golf course runs through the former HF antenna farm; special rules addressed hitting a tower with a ball (usually stroke and distance). The NSS HF receiver station, and the headquarters for NavCommStaWashingtonDC(T), was located at the Naval Communications Station in

Cheltenham, Maryland Cheltenham is an unincorporated community in Prince George's County, in southern Maryland, United States, adjacent to U.S. Highway 301. It is named after Cheltenham, Gloucestershire, England. History The Cheltenham Youth Detention Center, a juven ...

until 1969. In late 1969, the receiver station at Cheltenham closed and a new receiving station was activated at

Sugar Grove, West Virginia Sugar Grove is a community located in Pendleton County, West Virginia, United States. Its ZIP Code is 26815. It is located within the United States National Radio Quiet Zone. The community was named for a sugar orchard at the original town site. ...

.
NSS began transmitting in September 1918
using a pair of Federal Electric 500 kilowat
Poulson Arc transmitters
However, arc transmitters were significantly inferior to the then state-of-the-art

Alexanderson alternator An Alexanderson alternator is a rotating machine, developed by Ernst Alexanderson beginning in 1904, for the generation of high-frequency alternating current for use as a radio transmitter. It was one of the first devices capable of generating th ...

and one of the arc transmitters was replaced by a more modern TAW 300 kilowatt vacuum tube transmitter in 1931. VLF, or "longwave" radio was the standard at the time for long-range radio transmission, only to be replaced by

shortwave Shortwave radio is radio transmission using radio frequencies in the shortwave bands (SW). There is no official definition of the band range, but it always includes all of the high frequency band (HF), which extends from 3 to 30 MHz (app ...

in the early 1930s. VLF later became essential for communicating with submerged submarines, a critically important capability as submarines became strategic missile platforms. The NSS transmitter fed one million watts of radio energy to its antenna, and during idle times, transmitted the string "W W W VVV VVV VVV DE NSS NSS NSS" in

Morse code Morse code is a telecommunications method which Character encoding, encodes Written language, text characters as standardized sequences of two different signal durations, called ''dots'' and ''dashes'', or ''dits'' and ''dahs''. Morse code i ...

. The power was so high and the frequency so low, one could hear the signal on practically any kind of receiver anywhere in the Annapolis area. Messages were also sent in Morse code, but were either prearranged code signals or were encrypted. Rendered obsolete by

satellite A satellite or an artificial satellite is an object, typically a spacecraft, placed into orbit around a celestial body. They have a variety of uses, including communication relay, weather forecasting, navigation ( GPS), broadcasting, scient ...

technology and the end of the cold war, NSS ceased operation and all of the antennas and most of the towers were demolished in 1999. Three of the smaller 600-foot towers were preserved near the tip of Greenbury Point to serve as aids to navigation for boaters on the Chesapeake Bay. The callsign, operating from Annapolis, was brought back for the May 8, 2021 Armed Forces Day radio test. This is an annual event when

amateur radio Amateur radio, also known as ham radio, is the use of the radio frequency radio spectrum, spectrum for purposes of non-commercial exchange of messages, wireless experimentation, self-training, private recreation, radiosport, contesting, and emer ...

operators can work through crossband communications with certain military stations. The station was active for 16 hours.Armed Forces Day 2021
/ref>

References

External links

* Communications and electronic installations of the United States Navy Buildings and structures in Anne Arundel County, Maryland Towers in Maryland Military radio systems Military installations closed in 1999 Communications in Maryland 1918 establishments in Maryland {{Maryland-struct-stub Closed installations of the United States Navy