American television directory (1946)

PIONEERING A TELE-RELAY NETWORK Philco reports satisfactory tests of the multiple relay type of network over its Washington-Philadelphia link. By JOHN BALLANTYNE. President, Philco Corporation T he growth of television networks logically depends upon two factors: first, the technical development of tele¬ vision transmitting and relaying equip¬ ment; second, the economic justification for the expansion of television service. From the technical standpoint, Phil¬ co has done considerable pioneering in the development of television relay net¬ works. Our first step along this line was a logical advance from our long and successful experience with remote pick¬ up telecasts. For several years, Philco engineers have taken their television cameras to televise interesting news events such as the famous Mummers’ Parade in Philadelphia. All Penn football games at Franklin Field for the past five seasons have been televised by Philco crews using two cameras to bring the gridiron ac¬ tion to the Philadelphia television audi¬ ence. Such remote pickups have been relayed over a relatively short distance to our main transmitter, Philco Tele¬ vision Station WPTZ at Wyndmoor, and then re-broadcast. With the benefit of this experience, our engineers opened a successful tele¬ vision wireless relay link between New York and Philadelphia, in co-operation with the National Broadcasting Com¬ pany. At first, from October 1941 to July 1942, programs transmitted from New York by WNBT were picked up at a relay station at Wyndmoor just outside Philadelphia, and thence beamed to our main transmitter, then located at the Philco plant at C and Tioga Sts., Philadelphia. Relaying in this • way, from New York to Wyndmoor in a sin¬ gle “hop,” was not entirely satisfactory because the distance was too great for true line-of-sight transmission. Relay Passes 3-Year Test This problem was solved by develop¬ ing new relay equipment and placing it at Mt. Rose, N. J., about half way between New York and the main Philco transmitter, which has been at Wynd¬ moor since July, 1942. With line-ofsight relaying, this tele-network con¬ necting New York and Philadelphia has been providing television pictures of commercial quality for more than three years. On V-E Day, it was in suc¬ cessful operation continuously for 14 hours, relaying the special WNBT pro¬ grams to the Philadelphia television audience through Mt. Rose and WPTZ. Recently Philco engineers carried their pioneering experiments another step forward by joining Washington with Philadelphia via a multiple relay television network. In this relay sys¬ tem there are four intermediate relay stations in addition to the originating transmitter in Washington and the re¬ broadcasting transmitter at WPTZ in Philadelphia. All relay stations are sit¬ uated on hill tops for best televisibility. The longest transmission path between stations is about 43 miles so that lineof-sight relaying is assured. The new Washington-Philadelphia multiple relay network performed splen¬ didly throughout its first public dem¬ onstration, on April 17, 1945, when the first telecast ever made from Washing¬ ton was seen and heard by the Philadel¬ phia television audience. Picture qual¬ ity was commercially satisfactory. The major point proved by this net¬ work is that it is now entirely possible and practical to connect distant cities by a series of television relay stations. Undoubtedly, television relaying will b~i FIRST LINK in the Philco network, at Arling¬ ton, Va., uses 100-foot dipole-topped an¬ tenna towers for line-of-sight transmission. eventually be accomplished at much higher frequencies than the present 12mc. channels, centered around 210 and 236 me., now being used by Philco. However, it is also entirely possible that networks can be built in the near future, utilizing present equipment, techniques and frequencies, joining many other major metropolitan areas in the United States. If the relay sta¬ tion sites are carefully chosen, as was the case with the Philco networks con¬ necting Washington and New York with Philadelphia, it will be possible to use the same sites and many of the same facilities at the more desirable re¬ laying frequencies above 1000 me. in future tele-network operation. Networks Stimulate Revenue As to the economic problems in tele¬ vision networks, I believe that we can draw a parallel with the infancy of radio broadcasting. At first, local radio stations presented local programs. Au¬ diences were limited, advertisers could afford to pay relatively little, and thus it was hard to build program quality. When radio stations were linked in na¬ tional networks, programs immediately improved as more money could be spent for talent, writing, direction and preparation, while technical research could also be expanded. Television programming is in its in¬ fancy now because television networks are just beginning to be built. There are still only nine television stations operating in the United States, and only three of these are linked together and these for relatively short periods each week. When television networks spread across the country, as I believe they soon will, and the television audience expands from a few thousand persons to hundreds of thousands, the economic justification will exist for more elabo¬ rate and hence more expensive televi¬ sion programs. To date, relatively few advertisers have cared to experiment with television because of the limited audience, even though time charges have been nominal. But now, with civilian goods return¬ ing to the market and keener competi¬ tion for sales becoming inevitable, ( Continued on page 140) 27