Radio annual (1941)

FREQUENCY MODULATION By LT. COL. GUSTAVUS REINIGER Radio Engineering Laboratories, Inc. IN 1940 Frequency Modulation (F.M.) has climbed dramatically out of the experimental classification to win the F.C.C. stamp of approval as a full fledged commercial broadcasting service. Three years ago Radio Engineering Laboratories, Inc., co-operating closely with the inventor, Major Edwin H. Armstrong, was the only manufacturer devoting an important part of its attention to F.M. transmitter equipment. Today there are three other large companies in this field : Western Electric, General Electric and R.C.A. ; while Westinghouse is reported to be also planning to come into the field. ority of F.M. show up with greater clarity, just as this super-mechanized war has made all other kinds of excellence in technical equipment much more pronounced. Besides its peace time excellence, F.M. is almost impossible to jam. Long distance aerial raiders would not be able to use F.M. stations to ride into the United States on their guiding signals, but all A.M. stations will have to be shut down whenever an air-raid is imminent, as is now done in Germany. F. M. Networks What about F.M. networks? During the past year repeated successful demonstrations have been given of relaying F.M. programs through four to seven stations, without the slightest impairment of the program. This ability to relay programs through dozens of stations is one of the greatest powers of F.M. It makes for an elasticity of combination quite impossible with the A.M. system of broadcasting. Several F.M. networks have been under discussion for some months. During the coming year one or more of these will probably take definite commercial form. Will F.M. pay? There are already thousands of enthusiastic listeners. The next year will make this number millions. F.M. is ideal for automobile radio. It eliminates all the noise, but it is still so young that this important phase has had almost no discussion. Major Armstrong recalls the time some years ago when he expressed the opinion that a superhetrodyne A.M. receiving set could not be manufactured for less than $100.00. He invented the Superhetrodyne just as he did F.M. We are now all familiar with the thousands of Superhetrodyne A.M. sets that sell for $9.00 to $15.00. So Major Armstrong now says, "If the public wants F.M., ways will be found to meet every man's pocketbook." Three years ago no one was manufacturing F.M. receiving sets in quantity — today there are more than twenty-five thousand sets in use, most of these sold in the past six months. Ten or more manufacturers are making F.M. receivers and combinations. Radio dealers generally, where F.M. programs can be heard, are reporting increases in sales volume of 40 per cent or more because of F.M. interest. A very good all-use combination (shortwave, standard radio, 10-record changer, and F.M.) has sold a record volume in a New York department store priced at $139.50. A good table model set with standard radio and F.M. sells for $70.00. A considerable number of F.M. tuners which are designed to add F.M. to present radio sets have been bought by the public. Frequency Modulation development seems to be following in the footsteps of its predecessor A.M. A year and a half ago anyone could have applied for a one-kilowatt experimental F.M. transmitter and got on the air promptly. In metropolitan centers such as New York City, Chicago and Philadelphia it is already doubtful whether there will be enough frequencies for all those who wish to enter this new method of broadcasting. Besides leaders in the present broadcasting industry, leaders in other industries are applying for and getting construction permits for F.M. stations, notably newspapers and department stores in New York City, Baltimore and Los Angeles. At time of going to press, due to limitations by the FCC and its regulations regarding F.M. Broadcast stations, New York City has a greater number of applications than there are available frequencies. F. M. and the War The participation of the United States in a major war is an item of uncertainty to some prospective F.M. broadcasters. It is likely however, that the vagaries of a modern war will only make the superi 705