Radio Broadcast (Nov. 1925-Apr 1926)

676 RADIO BROADCAST APRIL, 1926 FIG. 2 wls, with studio in the Hotel Sherman Annex in Chicago. This well-known station is maintained by the Sears-Roebuck Agricultural Foundation. Curtis D. Peck is the chief operator. The power plant is located on a twoand-a-half acre plot on the Dixie Highway, just south of Crete. The site is landscaped, with ample drives and parking space for visitors. The lawns cover some fifteen miles of ground wire, plowed in during the period of construction of the station. The building contains a large operating room, an office, a reception room for visitors, generator and battery rooms, switch closets, and an entrance hall. The construction is up to date in every respect, including factors affecting radio transmission. The layout and joining of metal lath, for example, is such as to minimize radio frequency losses. An elaborate water cooling system for the tubes, with provision against freezing during the winter, has been provided. The towers, measuring forty feet at the base, and two hundred feet high, are visible from the Indiana state line. The transmitting set is a product of the Western Electric Company. The wavelength is 344.6 meters, corresponding to 870 kilocycles. The Army experimental call letters are a z 3. The studio on the sixth floor of the Hotel Sherman Annex was fixed up by a wellknown interior decorator with the aim of expressing the radio motif (on the nature of which there may not be perfect agreement). According to an announcement, "Every piece of equipment and furniture, the walls, ceiling and lighting fixtures . . . emanate the speed, intensity, and universality of the mysterious forces of the air." Black, red, and silver are the colors, with representations of sound waves on the walls and ceilings, giving the visitor the impression that "he has stepped inside of Einstein's brain." Well, at last someone understands Einstein. There are two studios. One is 55 feet long and 20 feet wide, for orchestras, bands, and dramatic productions; a smaller studio accommodates soloists. Separated from the larger studio by a plate glass window is a miniature theatre which is to be open to the public. It seats about 50 people, who hear the program through loud speakers while watching the broadcasting. The usual reception room, offices, operating and battery rooms are of course included. Broadcast Transmitters and Tuning c OMMENTING orally on the substance of my remarks on "Broad Waves and Sharp," in the March issue, in which I let loose a few growls at the broadcast listeners and operators who labor under the delusion that a c.w. telephone station can "sharpen" its wave in some recondite manner, Mr. John V. L. Hogan, the well-known consulting engineer and Past President of the Institute of Radio Engineers, points out that there is one case in which a broadcasting station may contribute to broad tuning at the receiving end. That is when the carrier frequency fluctuates with modulation. This malady is probably a rare one among broadcasting stations worth listening to, but it may occur among some of the loose and flapping small time agitators of the ether, so let it be included for the sake of completeness. Mr. Hogan discussed this complaint in the September and October, 1924 numbers of Popular Radio. If the fluctuations are rapid enough, such a carrier will not only tune broadly, but it will be noisy. I think even in this case we should not apply the terms "sharp" and "broad" to the carrier, but should refer to its "steady" or "fluctuating" nature, as the case may be. The term "broad" should be reserved for the tuning of receivers, and the radiation of spark transmitters, with their adjustable decrement. For that matter, the broadness of tuning of every c.w. transmitter varies with modulation. The carrier, the carrier plus the modulating frequency, and the carrier minus the modulating frequency, are the three frequencies radiated. Hence when emitting a note of high musical pitch a station should tune somewhat broader than when its carrier is modulated down in the bass. Whatever broadness of tuning is introduced in that way is a consequence of the fundamental function of the station. Again, there is a practicable form of radiation, called "single side band transmission," in which the carrier and one side frequency are suppressed at the transmitter. A substitute carrier is introduced at the receiver, and the modulation reproduced by the use of the single side frequency which is radiated. This method is very economical in that it requires a much narrower frequency band per station, and consequently allows more channels to be crowded between given frequency limits. It has not yet been introduced into broadcasting, so this is as far as we shall let it worry us for the present. Radio Lingo, Past and Present Miscellaneous Influences: The Novice BEGINNERS in the radio art, and the public in general, say, "My radio" where initiates refer to "my receiver," or "my receiving set" or, more loosely, "my radio set." The broadcast listener is interested only in receivers, so a receiver is a "radio" to him. The same slackness is evident in the "23-plate" nomenclature for condensers. The beginner is not interested in capacitance, which is a concept and takes some experience and thought to grasp, but he can see and count, and so condensers are sold by the number of plates rather than by the essential factor of capacity. We may expect a widening gap between the engineering and selling terminology of radio, for the engineering interests will * certainly not give up their ways of calculating and designating, and the public cannot be expected to take up the engineers' way of looking at things. Among other influences that have formed radio terminology is that of the sea. We have all heard the announcer say, " Please stand by for the next feature on our program." Now, "stand by" is a general term meaning "to be near,' "to be present." As a nautical term it means "get ready," as "Stand by to launch the boats." This phrase entered radio apparently by the nautical route, but had to undergo a change in meaning to "Wait a minute; I'll be with you shortly." When two ship stations called a coast station, the land operator would tell one of them to "stand by." The early tuners had a "stand-by circuit" — a broadly tuned circuit, picking up any signal within a wide range of wavelengths. Many an old operator remembers the musical swing of Cape Race's "std bi" in the dim romantic spark days. And now the broadcast announcers have it. An honorable and manly phrase of deep salt water, it has become a prefix to jazz orchestrations. Past, Present, and Future SO RADIO has passed from the backyard-spark coil-coherer stage to the universal communication level, and ways of speech have changed with it. In the early telegraph days the note or tone of the signals was anything. The object was just to get a sound through. The Marconi spark coils, with their gastric growling, were supplanted by the sixty cycle spark, because sixty cycles happened to be handy. Gradually aspirations for a musical note took form and the question arose, "How's his note?" when one was speaking of a station. A decade later the question is, "How is their quality?"