Dixon, California -
A United States Shortwave Mecca
By John Schneider, W9FGH
(Click on photos to enlarge)
This photo of the AT&T/KMI transmitting station in Dixon was probably taken in the 1950s. The building was constructed in 1931, when the station first opened. The site is vacant and unused today. (Maritime Radio Historical Society)
The Transpacific Telephone Company, Dixon, 1931: The rhombic antenna is seen from end aimed towards Hawaii. (Author’s collection)
The Transpacific Telephone Company, Dixon, 1931: The transmitter is located at left, with the power control board at right. The shelf at the near end of the transmitter holds a telephone for communication inside and outside the building, and a telegraph sounder for communication with the Point Reyes receiving station and the San Francisco control office. The second transmitter panel from left holds dials for the first frequency tuning operations. (Author’s collection)
A 1952 aerial view of the Voice of America Dixon, California, transmitter site, looking south towards the towers of the recently-completed Sterba curtain arrays. The original World War II rhombic antennas are seen to the right. (Courtesy of Bill Newbrough)
This aerial view of the Dixon transmitter building shows the security tower, AC power transformers, generator building, and the antenna switching array. (Courtesy of Bill Newbrough)
This is a ground view of the transmitter building. The operator’s control room was located behind the lobby in the center of the building, and the transmitters were housed in the East and West wings. (Courtesy of Bill Newbrough)
This 1952 photo shows one of the Voice of America’s new 100 kW General Electric G-100-A transmitters in Dixon. The left cabinet contains the low level RF stages and the middle cabinet holds the RF power amplifier. The modulator section is located beyond the transmitter access door. (Courtesy of Bill Newbrough)
This is the rhombic antenna array that was installed by NBC in 1943. Eventually, the site had ten rhombic antennas aimed at different target areas. Several of these were reversible. (Courtesy of Bill Newbrough)
These Sterba curtain arrays were erected in Dixon in 1952. The center tower is 305 feet tall and the end towers are 325 feet tall. There are 700 feet of antennas stretched between the towers. The northern antennas target Northern Asia, while the southern set is aimed at The Philippines. (Courtesy of Bill Newbrough)
This view shows the complexity of the curtain arrays themselves. There were four separate curtain antennas suspended between each set of towers. (Courtesy of Bill Newbrough)
This was the original antenna switching matrix. It was operated remotely from the control room and could connect any transmitter with any antenna. The switching was accomplished with cables and pulleys. As the site grew, this was later replaced with a pneumatically-controlled switching matrix. (Courtesy of Bill Newbrough)
ABOUT THE TOWN OF DIXON:
If you take a drive from San Francisco to Sacramento along Interstate I-80, you’ll pass through the pastoral town of Dixon, California. This has always been prime agricultural land – it’s pancake-flat, blessed with a temperate climate, fertile soil, and ample water, fed from the surrounding estuary of the San Joaquin-Sacramento River Delta. The area is one of the most productive farming regions of the United States, and has historically been the home to dairy farms and nut orchards.
As you drive along the freeway, you’ll also notice large fields of radio antennas sprouting off in the distance towards the south. That is your only clue that this quiet, suburban farm town is also one of the country’s prime locations for shortwave propagation. Starting in the 1930s, this fact was recognized by both private companies and the U.S. government, and antenna masts began sprouting at several radio sites for both point-to-point and broadcast transmissions aimed at Alaska, Hawaii and the far reaches of the Pacific.
AT&T TRANSPACIFIC TELEPHONE:
The first company to take advantage of Dixon’s radio properties was the Transpacific Telephone Company, Ltd., a subsidiary of AT&T, who purchased a site on Midway Road in 1930. The goal was to establish commercial two-way radio telephone service between the mainland and Alaska, Hawaii the Philippines, and ships at sea. Trans-Pacific undersea telegraph cables had been in use since the beginnings of the century, but this project would offer the first voice telephone service.
AT&T had operated a Trans-Pacific radio telegraph service since 1921. It was licensed as KMI and operated from Pt. Reyes on the coastline North of San Francisco. The Dixon operation was structured as a major expansion of KMI, with its transmitters at Dixon and receivers at Pt. Reyes. Five frequencies were authorized between 7,000 and 21,000 kHz. (KMI’s sister stations, WOO and WOM, already provided Trans-Atlantic service on the East Coast.)
Regular service to Hawaii was initiated in early 1932, with several 20 kW water-cooled transmitters feeding 500-foot-long “Double Vee” (rhombic) wire antennas oriented to favor skywave radiation towards the Pacific Ocean. By using separate transmitter and receiver locations, full duplex telephone operation could be provided. The radio signals were scrambled to ensure caller privacy.
On the Hawaiian end, an RCA receiving station at Koko Head and a transmitter site at Kahuku Point on Oahu connected to the Mutual Telephone Company. Low power radio signals then were used to connect Oahu with the other Hawaiian Islands.
Placing a call to Hawaii through this system in 1932 was an expensive proposition. A three minute call cost about $285 in today’s dollars. Also, due to the limitations of shortwave propagation, calls could be made only from 10:30 AM to 6:30 PM.
The site grew in size and complexity over the years, and the staff needed to man the site grew accordingly. At its peak, there were 30 transmitters and 36 different antenna systems strung between wooden poles, each with its own specific target zone. While operating for most of its life as a civilian commercial service, World War II saw the Dixon facility pressed into heavy service for communications with units of the armed forces in the Pacific.
Regular operation continued through the 1980s, but competition from communication satellites and multiplexed undersea cables eventually drove the shortwave telephone service into obsolescence. With only about twelve customers remaining, AT&T finally closed its Dixon site in 1991. Globe Wireless then acquired the site and utilized it for digital communications with ships in the Pacific, but in 2013 the company was bought by Inmarsat, and all of its maritime HF service have since been closed. The KMI site was recently sold to a neighboring rancher, and the antennas are being removed.
When the Japanese attacked Pearl Harbor in 1941, the United States suddenly and unexpectedly found itself at war in the Pacific. There was an urgent overnight need for shortwave radio stations to broadcast news and information to the populations spread throughout the war regions, but there was only one U.S. shortwave station that could be heard in the Pacific – General Electric’s KGEI in San Francisco. In its pre-war regulation of radio, Congress had expressly prohibited the government from owning or operating any radio stations, including international stations, with the result that an entire broadcasting infrastructure needed to be put together overnight.
A new government agency, the COI (Coordinator of Information - later renamed the O.W.I., Office of War Information) was created in 1942, and studios were set up in New York and San Francisco to produce round-the-clock programs for foreign consumption. While the government could not legally operate its own shortwave stations, it was not prohibited from leasing them, and so in 1941 President Roosevelt called a meeting of important broadcasters from around the country to put together an emergency network of shortwave facilities. General Electric, Westinghouse, NBC, and CBS all made their peacetime shortwave stations available to the government on a continuous, around-the-clock basis, and Powel Crosley of WLW in Cincinnati and Wesley Dumm of KSFO in San Francisco both agreed to build new stations that it would lease to the government. On the West Coast, KSFO built shortwave stations KWID and KWIX for the O.W.I. and also leased studio space to the agency. But even so, it was evident that the three West Coast station (KGEI, KWID and KWIX) were not capable of covering all target areas in the vast Pacific Ocean, especially in the face of increased jamming from the Japanese.
In 1943, both NBC and CBS agreed to build new shortwave plants in California for the O.W.I. The facilities would be built by the networks under contract to the O.W.I., financed by a government loan, and leased to the O.W.I., who would provide all program services. CBS chose a location at Delano and put stations KCBA, KCBF and KCBR on the air in November, 1944. NBC selected a 160 acre site on what is now called Radio Station Road in Dixon.
NBC engineer Carl Deitsch supervised the design and construction of the million dollar project. Deitsch was NBC’s shortwave broadcast expert, having done the same job previously for its shortwave stations in Bound Brook, New Jersey. He was assisted by others from the crack NBC engineering team, including key men from the NBC broadcast stations KPO and KGO in San Francisco. Construction began in 1943 with the installation of two 50 kW Federal Telegraph Co. transmitters. Rhombic antennas targeted Japan, Australia and the Philippines. Broadcasting commenced on December 27, 1944, with the call signs KNBA and KNBC. The next year, two more RCA transmitters were added, using the call signs KNBI and KNBX.
The original Federal transmitters were radio telegraph (CW) systems, and were fed by separate Federal modulators. One modulator fed two transmitters, which was possible because they shared common programs. Federal later built a 200 kW transmitter for Dixon.
By the end of the war, the Pacific was being flooded with American shortwave broadcasts from 17 West Coast transmitters and new facilities in Hawaii and Saipan. As the tide turned in the battle against the Japanese, the programs increasingly shifted from propaganda aimed at occupied countries to programs aimed at the American servicemen. These included rebroadcasts of standard network fare, popular music, and play-by-play sports. The stations were an important link to home for our servicemen in the far-flung Pacific. The name “Voice of America” was first heard at this time.
The O.W.I. was closed after the war, and the shortwave services were transferred to the State Department’s new O.I.I. – Office of International Information. In 1953, the shortwave service – by now formally called the VOA – Voice of America – was transferred again to a new agency called the U.S. Information Agency – U.S.I.A. The transmitters were still being leased from the networks and commercial broadcasters, and they continued to be the station licensees, responsible for operating and maintaining the sites. All costs were reimbursed by the federal government. At the close of the Korean War in 1952, the huge operating costs briefly came into question and the House cancelled funding for the leases of shortwave stations except those being operated by NBC, CBS and WLW. KGEI reverted to a civilian operation managed and programmed by General Electric; KWID and KWIX were closed, and the transmitters were sold to the Far East Broadcasting Company who moved them to the Philippines. However, by 1953 the Cold War was raising its head, and full VOA funding was soon restored. The Dixon site got two new GE 100 kW transmitters and new towers supporting two large Sterba curtain arrays that were rated up to 500 kW.
NBC operation of the VOA shortwave sites continued through the 1950s, and a large staff of company engineers kept daily watch over the Dixon facility. When television became the new primary broadcast medium and NBC cut back its radio staffing in San Francisco, many of the lower seniority engineers were transferred to Dixon, where they bumped men who had even lower seniority.
The government leases of the VOA shortwave stations were formally terminated on November 1, 1963, and the VOA took ownership of the Dixon, Delano and Bethany, Ohio (WLW) facilities. Most of the former NBC engineers in Dixon stayed on and became civil servants. The Dixon plant was modernized again in 1965 with a building expansion and the addition of three Collins 250 kW transmitters.
Another part of the Dixon VOA operation was a separate receiving station, 25 miles away in Rio Vista. It was used for receiving and relaying program feeds from the VOA and other international broadcasters. When the transmitting site was updated in 1965, new RCA R-3 receivers were also installed at the receive site, which operated daily until 1979.
After the Cold War finally ended and newer, cheaper methods of satellite program delivery became available, the VOA began decommissioning its expensive shortwave operations. Bethany, Ohio was closed in 1994. Delano was closed in 2008. The Dixon and Rio Vista sites were mothballed in 1979, but the transmitter site was put back into service in from 1983 transmitting Spanish language programs to South America. (The receive site was never manned again.) At time of its final closing in 1988, there were ten transmitters in Dixon.
The Dixon and Rio Vista sites were finally
declared as surplus in the 1990s, and the G.S.A. put the facilities up for
auction. In 1998, both the transmit and
receive facilities was sold to local ranchers for a reported $160,000 and
$25,000, respectively. Aeronautical
Radio, Inc. (ARINC, a division of Rockwell-Collins) leased the Dixon site and
operated an aeronautical trans-Pacific HF service there. Globe Wireless leased the Rio Vista receive
site for its HF maritime data communications service. Both companies have since been ceased
operations, and the sites are in the process of slowly being dismantled. The Sterba Curtain towers in Dixon are reportedly
still standing, and the remnants of the GE and Collins shortwave transmitters
are said to be still in place. U.S. NAVY TRANSMISSION SITE:
U.S. NAVY TRANSMISSION SITE:
The experience of World War II also motivated the U.S. Navy to establish a communications base in Dixon in 1947. The U.S. Naval Radio Transmitting Facility was built on a parcel of more than a thousand acres located adjacent to the NBC shortwave facility on Radio Station Road. The base housed a number of VLF and shortwave transmitters and antennas, a large complex of antennas, and housing for Navy personnel and their families.
The Navy operated the Dixon communications
base from 1947 to 1979, and then turned operations of the facility over to a
contractor. Rome Research Corporation, a
subsidiary of PAR Technology Corp, continues to operate the site today. The site houses a number of wideband conical
antennas and one ELF (Extremely Low Frequency) antenna. It is also the transmitter location for the
Air Force "West Coast" High-Frequency Global Communications System
(HF-GCS), which is remotely controlled from Andrews AFB Maryland. The former naval housing community is now a "migrant
housing center" operated by Yolo County.
A majority of the original 1,314 acres has been contracted as
The heyday of shortwave communications has clearly passed. More modern, efficient and dependable means of global high-speed communication are now available, and they all operate at lower cost than the last generation’s “big iron” radio solutions. However, all of these new communications systems make use of an intermediate infrastructure – satellites, leased data lines, the Internet, or relay broadcasting through intermediate local radio stations. The latter option is particularly risky for the VOA, as a foreign unfriendly government can close down the local rebroadcasting of VOA programs at any time. The advantage of shortwave communication has always been its ability to reach around the globe without benefit of any intermediate technology –nothing exists between the broadcaster and the listener except the ionosphere. If some unforeseen global crisis should again occur, the world may someday regret that it has abandoned so many high powered international communication sites, like Dixon. We may someday see another crash program and a rebirth of shortwave, repeating what occurred in the U.S. in 1942.
“Broadcasting on the Shortwaves, 1945 to Today” by Jerome S. Berg
“The Early Shortwave Stations: A Broadcasting History Through 1945” by Jerome S. Berg
Broadcasting Magazine: 12/25/44, 7/24/44, 2/14/49
Newspaper articles of the time:
Correspondence with Bill Ruck, Marine RadioHistorical Society
Interview with former Globe Wireless operator Chris Campbell, 6/5/2014
A Visit to the KNBC Belmont AM Transmitter in the 1950's by Fred Krock
NOTE: This article first appeared in the "Spectrum Monitor" in July, 2014.
John F. Schneider & Associates, LLC