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This is the story of the U.S. Navy’s station NAA, the
country’s most important radio communications facility for almost 30 years.
THE NAVY DISCOVERS THE BENEFITS OF RADIO:
The U.S. Navy first became interested in radio in 1899 when
it observed New York Herald reporters sending back dispatches from the America’s
Cup Yacht Race using Guglielmo Marconi’s wireless equipment. Before long, Marconi and de Forest sets were
installed on several Navy ships. Initially,
this spark equipment was useful only for communicating short distances between
ships. That prompted the Navy to plan a
high-powered central communications station, assigned the call letters
NAA. In its first tests of long-distance
wireless telegraphy, NAA was able to successfully communicate with the U.S.S.
Delaware off the Azores in the Eastern Atlantic.
The site for NAA, selected in 1910, consisted of a 13.4 acre
section of the Army’s Fort Myer located at 701 Courthouse Road in Arlington VA,
across the Potomac River from Washington DC.
The land was transferred from the War Department to the Department of
the Navy by an Act of Congress.
Construction began in 1911 and transmitters were installed in 1912.
NAA’s three giant self-supporting towers were a local
landmark, called the “Three Sisters”.
The main tower was 600 feet tall, and the two others were 450 feet, each
spaced 350 feet apart. Their 1,050 tons
of steel were supported atop blocks of marble.
The buried ground system covered the entire 13.5 acres.
The towers initially supported three flat-top antennas made
of phosphor-bronze wire. The two west
ends of the flat tops were unconnected at the 600 foot tower, while the
sections between north and south towers were tied with jumpers to the other
flat tops. The downlead to the
transmitter was a fan shape 300 feet in length, with all wires bunched together
at the building entrance. The antennas
could be lowered by electric winches for periodic maintenance.
NAA’s total
construction cost was $300,000 ($9.6 million in today’s dollars). It was manned by a crew of six with an
operating budget of $18,000 per year.
The first transmitter was a powerful 100-kW rotary spark
unit designed by Reginald Fessenden. The
spark gap rotor was belt-driven from a 200 H.P. motor. Testing began in 1912, with the first
official transmissions taking place on Feb. 13, 1913.
SPARK VS. ARC:
Shortly after NAA opened, the Federal Telegraph Company
pressed the Navy to try out one of its Poulsen arc transmitters. (The
arc transmitter was a sealed chamber in which an electrical arc burned in
hydrogen gas between a carbon cathode and a water-cooled copper anode.) The Navy was at first reluctant, but after
some political pressure they agreed to a test.
Federal installed one of their 35-kW arc sets and Rear Admiral George
Clark conducted a coverage test aboard the U.S.S. Salem on a cruise to Gibraltar,
with daily signal comparisons being made from each transmitter. The result was that the Federal arc
transmitter proved to be superior, and was able to maintain communications well
beyond the required distance of 3,000 miles. After this successful test, the
Navy ordered its first 100 KW arc unit.
Housed behind 6” thick doors and soundproofed walls, it became the
primary NAA transmitter until the advent of vacuum tube rigs, maintaining
regular daytime communication with Paris, San Francisco, and Darien, Panama. The original spark transmitter was retained
after negotiations with Fessenden, and it continued in use until 1923.
NAA’s receiving station was not in Arlington, but located
four miles away in the Navy Munitions Building.
Sending took place from the same location, with messages traveling by
wire to Arlington. Eight remotely-operated
transmitter keys could be simultaneously operated remotely at NAA.
After the successful deployment of NAA, similar Navy
stations were built at Darien, Panama (1913), Cavite, Philippines (1913), San
Diego (Chollas Heights, 1915), and Oahu, Hawaii (Hospital Point, 1916). In 1917, an adjoining three acres was
purchased for an expansion project at NAA.
The Three Sisters would now support six wire antennas: the main antenna, and one each for aircraft,
Army, Navy, voice, and later, broadcasting.
The property was officially incorporated as the community of “Radio
Township, VA”, and a post office with that name was even established.
The first experimental transatlantic transmission of speech from
NAA was conducted by AT&T in 1915, and heard in France and Hawaii. AT&T President Theodore Vail’s message
originated from the company’s offices in New York City It was the first time a voice from USA was
heard in Europe.
COMMERCIAL SERVICES OF NAA:
NAA was the WWV of its day, broadcasting time signals
provided by the Naval Observatory in Washington. This was critical to both Navy and commercial
ships at sea who needed accurate time to adjust their chronometers, essential
for determining their positions. The
time signals were also popular with amateur radio operators and anyone else who
needed accurate clock settings. Many
jewelers installed radio receivers in their shops to set their clocks. NAA’s time signals were broadcast for five
minutes each day at 11:55 AM and 9:55 PM.
Each second was a CW dot, with the 29th second omitted. The start of each minute was a long dash.
Weather forecasts were sent on a regular schedule by CW on
710 meters (420 kHz), with the information being received by wire telegraph
from the Weather Bureau. There were also
ten daily market reports from the Department of Agriculture. These same CW services were also broadcast on
longwave over NAT in New Orleans and NAJ at the Great Lakes Naval Base.
With the onset of World War I, the American public was prohibited
from owning or operating any radio equipment, including receivers. All wartime communications between the Navy
Department and U.S. forces in France were sent over NAA, as well as through
several commercial stations that had been impounded by the government (Marion,
MA; Tuckerton, NJ; Sayville, NY; and New Brunswick, NJ). All this encrypted message traffic was controlled
from a single room inside the Navy Department building in Washington. In 1918, the Navy constructed a 1200-kW transmitter
in France to provide service back to the U.S. The “Lafayette Station” was the world’s most
powerful at the time, but was not placed into service until after the war.
BROADCASTING:
After the war, once the public could again own and operate
radio receivers, regular voice broadcasts were implemented from NAA. Daily “radiophone” weather broadcasts were
now being sent at 10:00 PM EST each day on Medium Wave (the AM broadcast band),
along with the usual CW forecasts on 5,950 meters (50 kHz). Time signals, marine and land weather
reports, crop and market reports (“Hog Flashes”),ship orders and news bulletins
were also being sent on 2650 meters (113 kHz) using the original Fessenden
spark transmitter. On occasion, NAA was
also used to broadcast presidential messages.
After the advent of broadcasting in 1920, many local
stations would rebroadcast the NAA time signals so audiences who couldn’t tune
the longwave signals could set their clocks.
Starting in 1920, NAA itself began broadcasting occasional
entertainment programs to the public, along with sister station NOF in
Anacostia, D.C. Both stations broadcast
the dedication of the Lincoln Memorial on May 30, 1922. But because NOF was increasingly needed for
other duties, all public broadcasting was shifted to NAA in 1922, operating on
422 kHz using a 750-watt transmitter. In
1923, this unit was replaced with a 1,000-watt operating in the AM broadcast
band. The initial frequency used was 490
meters (611 kHz) , but this was moved to 434 meters (690 kHz) due to
interaction with other transmitters at the site. This NAA transmitter broadcast weekly Marine
and Navy Band concert broadcasts. The Departments
of Interior, Agriculture, Labor, War, Health, Internal Revenue, Treasury and
Commerce also took broadcast time for lectures on various topics.
In 1923, two additional 200 foot towers were constructed, as
well as 16 additional poles ranging in height from 25 to 70 feet, supporting
other antennas of various types.
In 1924, the dirigible Shenandoah broke away from its
mooring mast and was carried away by strong winds with its crew aboard. NAA maintained radio contact with the airship
for 9 hours. Eventually the crew was
able to get the ship under control, but it took over 400 ground crew to wrestle
it back to the ground the next day.
Starting in 1926, daily weather maps sent on 8000 meters (37
kHz) using the Jenkins system. This
specialized service was primarily of value to mariners.
VACUUM TUBES REIGN SUPREME:
By the mid-1920’s, NAA was operating six transmitters on
longwave, medium and shortwave frequencies, with operations shared between the
Army and Navy. The 30-kW arc transmitter
operated on the main antenna and was used by the Navy to communicate with Cuba
and Key West, as well as for broadcasting aeronautical and weather reports. There was a 500 kHz tube transmitter for
emergency marine communications; a 250
watt transmitter for airplane communications; another 250 watt rig for speeches
and concerts; and a 1,200 watt longwave
transmitter for band concerts and presidential addresses.
Reliable vacuum tube transmitters became available in the
early 1920’s, and their technical superiority quickly supplanted the older
technologies. The signals from spark
(damped wave) transmitters occupied a wide bandwidth, causing considerable
interference in the crowded longwave marine frequencies. To their benefit, the CW signals from arc
transmitters occupied less bandwidth, but generated “mush” noise adjacent to
their channel. They also created
substantial harmonic interference – measured as high as the 30th
harmonic. Even though modifications were
made to arc transmitters to reduce interference in later years, their days were
numbered once high-powered transmitting tubes became commercially
available. (see the Spectrum Monitor,
July 1922, article about William C. White)
By 1926, tube transmitters had replaced their predecessors in 27 shore
stations, with plans being made for another 14.
THE DEMISE OF NAA:
Over time, NAA gradually ended its public broadcasts, and its
time signals on 690 kHz were eliminated in 1936. But Naval Observatory time signals continued
to be sent on 113 and 9,425 kHz from NAA as well as from NSS in Annapolis. Gradually, all operations were shifted from
NAA to NSS, where three new 600-foot towers had been constructed in 1938. Finally, when Washington’s National Airport
opened in 1941, the NAA towers were deemed to be an aircraft hazard and were
dismantled, closing the station forever.
The original NAA buildings are still standing and are used by the Navy
today as office space.
The National Bureau of Standards station WWV began
operations in Greenbelt, MD, in 1945, taking over the task of broadcasting time
signals. WWV continues to provide this important
service today from Ft. Collins, Colorado
This article
originally appeared in the December, 2024, issue of The Spectrum Monitor
REFERENCES:
-
https://www.navy-radio.com/commsta/arlington.htm
- “News on the Air: The New York Herald, Newspapers, and
Wireless Telegraphy, 1899–1917”, by Noah Arceneaux https://themarconifamily.pbworks.com/f/News%20on%20the%20Air%20-%20Newspaper%20Wireless.pdf
- Wikipedia: https://en.wikipedia.org/wiki/NAA_(Arlington,_Virginia)
-
“Wireless Age” Magazine: Aug. 1915; Nov. 1923
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“Radio Broadcast” Magazine: Feb. 1923; July 1923; April 1924
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“Radio Age” Magazine:
Dec. 1922; March 1926; April
1926, Oct. 1926
-
“Radio Broadcasting News” (a Westinghouse publication): 3/19/1922; 3/17/1923
-
“AWA Journal”, Antique Wireless Association: Spring 2018
-
New York Herald, December 12, 1918
-
Smithsonian National Air and Space Museum, re the U.S.S.
Shenandoah:
https://airandspace.si.edu/uss-shenandoah-accessibility-version
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