Radio age research, manufacturing, communications, broadcasting, television (1941)

Record Details:

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ciple. The first police and fire do- partment radio systems operated on medium frequencies just above the standard broadcast band. A few years later a gradual swing to the use of channels in the 30- to 40- megacycle band began. However, this transition did not render the original systems obsolete and un- usable. Trend to Higher Frequencies "The first automatic radio relay- ing systems in the emergency com- munications service were in the 30 to 40 MC portion of the spectrum, but just prior to the war, a group of channels in the 116 to 119 MC band was allocated for such use. It can be seen, therefore, that the gradual tendency is toward higher frequencies and it is believed that the trend will continue. "The use of higher frequencies will result in lower-powered trans- mitting equipment, smaller-sized apparatus and highly efficient an- tenna systems. Higher frequency systems may be more readily con- trolled to cover the exact areas de- sired, thus making more efficient use of available power. Higher fre- quencies will also result in the availability of a large number of additional channels. "Perhaps this will open the way for many new radio applications and services. We may see two-way radio in common use by doctors, bus companies, trucking concerns, taxicab companies, railroads and many other similar users. Many of these services have been investi- gated in the past, but sufficient channels have not been available to permit the use of radio in such cases. The rapid advancements be- ing made in the radio and elec- tronic field may present a speedy solution to this problem." Higher frequencies also will lead to the more common application of automatic relaying units, Mr. Mickel said. Where great distances are to be covered and direct trans- mission is beyond the range of available equipment, automatic re- laying or repeater units may be interposed to pick up the transmit- ted signal and pass it along to the receiving point. "An example of automatic relay- ing is found in the radio system in operation on the Pennsylvania Turnpike," he continued. "Here, unattended relay stations pick up and pass along transmissions from one end of the turnpike to the other. A message originating at any point on the turnpike is clearly heard by all the cars patrolling the road, by all the toll office personnel, by Penn- sylvania State Police headquarters in Harrisburg and Bedford and in all maintenance buildings along the right-of-way. "This system has been in opera- tion for more than two years and effectively proves the practicability of such apparatus. The use of high- er frequencies will make such sys- tems more common and easier of accomplishment." As a development of the present- day fire alarm system. Mr. Mickel visualized a standard radio receiver wliich. when switched off at night. would maintain in operation a tiny leceiver which would connect the loudspeaker and pex'mit transmis- sion of any desired message when actuated by a specific signal from headiiuarters. Such a device would have wide apiilication in police and fire systems for calling out reserves or off-duty members, he said. "We will also see electronic heat indicators for actuating fire alarms," the engineer said, "and the burglar alarm of tomorrow may I'eadily u.se invisible light rays to prevent any visible indication that such a detection device is in opera- tion." Chicago Orchestra on NBC A major addition to the imposing list of NBC music offerings was the launching of "Orchestras of the Nation" on Saturday, March 25 (NBC, 3:00 to 4:00 p.m., EWT). First of the nation's great musical ensembles to be featured on the series is the Chicago Symphony Orchestra under the baton of De- sire Defauw. The Chicago Symphony is billed for the first five Saturdays of the series. Future orchestras are to be announced. Samuel Chotzinoff, manager of the NBC Music Division, partici- pated in the opening broadcast and was welcomed to the Windy City at a luncheon given by Edward L. Ryerson, president of the Orchestra Association.