Stratovision

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Stratovision was an airborne television transmission relay system using aircraft flying at high altitudes. In 1945 the Glenn L. Martin Company and Westinghouse Electric Corporation originally proposed television coverage of small towns and rural areas, as well as the large metropolitan centers, by fourteen aircraft that would provide coverage for approximately 78% of the people in the United States. Although this was never implemented, the system has been used for domestic broadcasting in the United States, and by the U.S. military in South Vietnam and other countries.

Technology

Because the broadcasting antenna for Stratovision is usually hung beneath the aircraft in flight, it naturally has a great command of line-of-sight propagation. Although transmission distances are dependent upon atmospheric conditions, a transmitting antenna 30,000 feet (9.1 km) above the Earth's surface has a line of sight distance of approximately 211 mi (340 km).

A Stratovision 25 kW transmitter operating from 30,000 feet (9.1 km) at 600 MHz will achieve a

of 2 millivolts per meter for a 30-foot (9.1 m) high receiving antenna up to 238 miles (383 km) away from the aircraft.

Early tests

Stratovision tests were undertaken between June 1948 to February 1949. The first phase was undertaken by the Glenn L. Martin Co. and Westinghouse using a twin-engine

.

The second phase of testing was undertaken by these companies using a stripped-down

in Baltimore, which was then relayed over a 5 kW video transmitter and a 1 kW audio transmitter for reception on 82-88 MHz with a television set tuned to Channel 6.

The aircraft received its originating signals from circular dipoles attached to a streamlined eight-foot (2.5 m) mast atop of the aircraft's vertical tail fin. The retractable 28 feet (8.5 m) long broadcasting antenna hung vertically beneath the aircraft. It was composed of a two-element turnstile array for video and a single-element circular dipole for sound transmissions.

The receivers, transmitters and necessary air-conditioning were all powered by the plane's engines using three 15 kVA, 500 Hz alternators. Without air conditioning the transmitters in the interior of the aircraft would have generated a temperature of 134 degrees Fahrenheit (57 degrees Celsius) with an outside air temperature of 25 degrees Fahrenheit (minus 4 degrees Celsius).

On 23 June 1948 the system's airborne transmitter rebroadcast the

The tests were watched by many television viewers who sent in reception reports. From these reports it was calculated that Stratovision would require only eight relay planes to provide a transcontinental network, and six additional planes to provide coverage to 78% of the United States. Charles Edward Nobles, the head of Stratovision for Westinghouse, said in his report:

"The major technical problems of the system have been solved, and the commercial development awaits only the crystallization of public demand for the expanded services offered by airborne broadcasting, application of the system by the radio industry to meet this demand, and the clarification of channel facilities available to make possible this application."

Sport

On September 30, 1954, Cuba used a

Education

In 1961 a nonprofit organization, Midwest Program on Airborne Television Instruction, commenced a Stratovision service from the airfield of Purdue University. The effort began as a three-year experiment funded by the Ford Foundation. The program organized, produced and transmitted educational television programs four days a week from a DC-6AB aircraft flying at 23,000 feet (7,000 m) over the community of Montpelier in north central Indiana.

MPATI delivered its programs to television channels 72 (call sign KS2XGA) and 76 (KS2XGD) in the UHF band, by transmitting videotaped lectures from the aircraft to an estimated potential 5,000,000 students in 13,000 schools and colleges. The aircraft were equipped with two 2-inch (51 mm) videotape machines and two UHF transmitters.

When MPATI signed on it used an

which was shown for five minutes before and between programs. The service ended in 1968 when it became embroiled in legal action over their application of Stratovision in a controversy with the Westinghouse company.

Propaganda

Vietnam War

During the Vietnam War, the

. The television programs were aimed at two audiences on two channels: one was aimed at the general public and the other was intended for the information and entertainment of US troops who were stationed in South Vietnam.

On January 3, 1966, a Broadcasting magazine article, "Vietnam to get airborne TV: Two-channel service —one for Vietnamese, other for U.S. servicemen—starts this month", noted:

Television broadcasting in South Vietnam ... begins January 21 and it's going to be done from the air. Two airplanes, circling 10,000 to 20,000 feet [3.0 to 6.1 kilometres] above the ground, will broadcast on two TV channels—one transmitting Saigon government programs; the other U.S. programs. The project is being handled by the

Super Constellations has been underway by Navy electronics experts at Andrews Air Force Base ... The project is an outgrowth of a broadcasting plane used by the Navy during the Cuban and Dominican Republic

crises when both radio and television were beamed to home in those countries.

The same article went on to report that during the Baseball World Series of October 1965 Stratovision had also been used to bring the games to the troops. The aircraft had picked up Voice of America radio broadcasts from California and relayed the signal to a ground broadcasting station. The Agency for International Development (AID) had purchased through the military Post Exchange Service, 1,000 monochrome, 23-inch television sets modified to operate on a variety of domestic power sources, and which had been airlifted to South Vietnam on December 28, 1965. They were to be put into community facilities around Saigon. AID was also spending $2.4 million to supply a total of 2,500 TV sets to South Vietnam.

The entire project was under the control of Captain George C. Dixon, USN. He claimed to be installing AM, FM, shortwave and TV transmitters on the aircraft which would get their power from an onboard 100 kW diesel-fueled generator. The planes would not only relay programs from film chain kinescopes and video recorders, but they would also have live cameras to create their own live programs.

Ground transmissions would be received from the aircraft on TV sets tuned to channel 11 for Armed Forces Television, and channel 9 for programs in Vietnamese. On radio the broadcasts would be tuned to 1000 kHz for AM and 99.9 MHz for FM.

On 7 February 1966, Broadcasting magazine reported that after working out a number of technical problems that the first show on channel 9 would begin at 7:30 p.m. and feature South Vietnamese Prime Minister

. After that the Vietnamese channel would be seen for one and half hours a day and the U.S. channel for three hours daily.

On 8 February 1966

.

1999 NATO bombing of the Federal Republic of Yugoslavia

Federal Republic of Yugoslavia

with slide show and narration based news. Quality of reception was very poor and area of coverage was rather small.

Iraq War

During the 2000s, the

EC-130 Commando Solo has been used to broadcast information and propaganda for the United States over a variety of television and radio frequencies. It has been used in several areas of operation, including Bosnia and Iraq

.

Pirate television

In 1969, news stories began to appear in the

Caroline Television instead.^[3] His plans called for two aircraft, one in service and one as a relief, which would transmit commercial television programs to Britain by Stratovision. Although these stories continued for some time, nothing became of the project. To date^[when?

] no pirate radio or television service has ever operated by means of Stratovision.

Use as a temporary service

The advent of

direct broadcast satellite

services has supplanted Stratovision as a permanent means of television delivery. The Stratovision concept continues to be used as a stop-gap measure where land-based transmitters are not possible and where large areas of territory need to be served with a television program.

Popular culture

• The plot of the 1986 comedy film
  B-29
  that was constantly in flight.
• A similar system, using helicopters, is mentioned in the 1950 Robert A. Heinlein story "The Man Who Sold the Moon".

References

1. Air & Space
   magazine, Vol 22 No 3, August 2007, "Broadcast Bomber", p. 18
2. ^ Guido Sapienza "Il sistema televisivo cubano", p. 67
3. ISBN 9781783376193
   .

External links

• "On the Air: The Story of Radio Broadcasting (Stratovision starts at 21 minutes)". Retrieved 25 March 2017.
• Midwest Program on Airborne Television Instruction (MPATI) records. Special Collections and University Archives, University of Maryland.
• "Stratovision". earlytelevision.org.