American television directory (1946)

TELEVISION NEEDS NORMAL DEVELOPMENT By G. B. JOLLIFFE Vice President in Charge of RCA Laboratories, Radio Corporation of America |t does not take much imagina¬ tion to see television as a possible five or even ten billion dollar enter¬ prise, employing thousands of men and women directly and indirectly. Television, like any other radio service, can be improved, and, like other radio services, it will go through several cycles of improve¬ ment and obsolescence — otherwise there will be no progress. We must continually pioneer. What is the nature of the im¬ provement which will be most ac¬ ceptable to the television audience? Should we wait for pictures with sharper definition, in color, or in three dimensions? All of these fu¬ ture additions may be desired by the public, and they will be achieved ultimately. These improvements must not be permitted to delay the establishment of a new industry and a new service to the public. As the television industry devel¬ ops, engineers have the obligation to see that the public gets better and better service and that the new developments which will be brought about by the stimulation of use are integrated into an over-all system. Engineers will not and should not be satisfied that the television job is done until they have made it possible to project, in the home, pictures of adequate size and in color of all major events wherever they occur, in the United States, or in any part of the world. These objectives may be accomplished in a few years, or many years may be required. However, we now know how to produce pictures of ade¬ quate size and quality in the home. The technique of bringing sports and news events, drama, opera, etc., to the home has been devel¬ oped to the stage where an ex¬ tremely entertaining program can be produced, broadcast and re¬ ceived. The public can enjoy tele¬ vision now. Its support of television will bring better television in the future. It should have the normal development of a new service, not hampered by unnecessary restric¬ tions or limitations and not retard¬ ed by those who may not have the will to pioneer or the inclination to enter a new field now. Hollywood to New York is obtainable with only eight airplanes as compared to 100 relay points on the ground. This greatly reduces the technical problems involved by virtue of requir¬ ing fewer handlings of the program. With directional antennas and utilizing relay frequencies on the order of 2000 megacycles, this relaying can be done between airplanes with powers of less than one watt. Tubes readily are avail¬ able which will generate powers of five watts in this frequency range. These relay stations could be designed to carry several television programs and also an abundance of other in¬ formation such as FM network pro¬ grams, facsimile, motion picture thea¬ ter television, etc. Altitude Limited by Planes Because the broadcasting service area and relay spacings increase with altitude and the power required to service the broadcasting area comes down as altitude is increased, it is desirable from a standpoint of radio operation alone to operate the plane at as high an altitude as possible. The altitude of operation of the sys¬ tem is limited by the economic and technical problems involved in operat¬ ing planes at extreme altitudes. A study of the over-all combination of radio and airplane operation indicates that an operating altitude between 30,000 and 50,000 feet provides a good compromise. Since we have more knowl¬ edge of the airplane design and oper¬ ating costs at 30,000 feet, I will pre¬ sent the system based on operation at that level. However, in the future we intend to operate at even higher alti¬ tudes. Multiple Service Planned In the early stages of thinking about airplane operation of broadcast sta¬ tions, it was felt that the operating costs for maintaining an airplane at high altitudes would be so great as to require that several transmitters be operated from one airplane, thereby realizing income from several paying advertisers. After preliminary talks with The Glenn L. Martin Company engineers, it was decided that the airplane design should be large enough to accommodate four television transmitters, five FM transmitters, monitoring equipment, and sufficient relaying equipment to carry four television programs and five FM programs, and also system com¬ munications channels. The airplane they have proposed is designed on this basis. Television and FM studios are lo¬ cated on the ground in the normal fashion. The program is fed into a small ground-to-plane link transmitter, picked up in the plane by a groundlink receiver, fed into the broadcast transmitter, and re-broadcast over the plane’s line-of-sight area by means of the broadcast antenna. When the plane functions as part of a program dis¬ tribution network, the signal from the ground-link receiver would also be fed into a small network-link transmitter and beamed to the next successive plane by means of a directional an¬ tenna. An 8-Plane Span of U. S. In a system covering the whole of the United States with television pro¬ grams from airplanes at 30,000 feet, each plane has a broadcast service range of approximately 200 miles in every direction and relaying can be ac¬ complished between two planes which are approximately 400 miles apart. By operating planes over New York, Pitts¬ burgh, Chicago, Kansas City, western Colorado, Salt Lake City and Los An¬ geles, a program distribution network from Hollywood to New York is estab¬ lished. These two cities are considered to be the main sources of television program material except for sports events and special events which might take place anywhere in the country. At the same time each of these planes broadcasts television and FM programs to an area of 103,000 square miles around its operating point. 14 Planes Serve 78% of Population By adding six more stations to this network — over Durham, Atlanta, Mem¬ phis, Dallas, Sacramento, and Portland, Ore. — approximately 51 per cent of the area and 78 per cent of the population of the United States is brought within the primary coverage area of 14 sta¬ tions. Almost any event in the country may be put on as a nationwide telecast with proper pickup facilities. Sports events, national elections, symphony concerts, Indian ceremonial dances, lo¬ cal disasters such as floods or hurri¬ canes, and a great variety of other program material could be fed into the network quickly by a small “pickup” plane, equipped with television cameras and relaying equipment, stationed at each Stratovision base. Such a plane could fly quickly to the desired scene and relay the program back to the main relay link for broadcasting nationally. In attempting to evaluate economical¬ ly the operation of airplanes for broad¬ casting, it is hard to find a concrete base for comparison. There is such a radical difference in the amount of tele¬ vision service obtainable by operating from airplanes as against operating ground stations that the two systems hardly have a common base. Selecting Pittsburgh as a typical op¬ erating center and the coverage from one airplane, eleven 50 kilowatt trans¬ mitters would be required to service the same area from the ground. Since one airplane serves the area with four television and five FM programs, an equivalent coverage requires 44 televi¬ sion transmitters and 55 FM transmit¬ ters, and approximately 33 relay sta¬ tions. It is assumed that the same pro¬ gram is fed into either system so that programming costs cancel each other. The operating cost for one Stratovi¬ sion station is estimated to be about $1,000 per hour. The cost for giving an equivalent ground coverage is about $13,000 per hour. This comparison does ( Continued, on page 127) 30