Radio Broadcast (May 1928-Apr 1929)

RADIO BROADCAST Sire $m |fork 5fimje0. ✓f////Je .Viiia TbalsFil la Print ' RA D I O STAT I O N TIMES SQUARE. NEW YORK s.s. 0132 WPAT. Eleanor Boiling November 22, 1928 TO Radio Broadcast, Hew York City. NOV 1% 1928 Please mail to catch S. S. Nalojra, leaving San Francisco, November 28th, i!ay, October and November issues Badio Broadcast, address 3yrd Antarctic Expedition, care Tapley, Dunedin, New Zealand. We are not leaving Dunedin for the ice barrier until arrival this mail about December 2.0th. Malcolm Hanson. Mr. Wing Pis airmail these to Frisco Meinholtz, Times This radiogram, signed by Lieut. Hanson, radio head of the Byrd Antarctic Expedition, shows that the explorers plan to keep abreast of the times on radio subjects by reading Radio Broadcast does not know what it is all about until after legislation is passed and the politicians playing with radio legislation do not intelligently protect the interests of the listener, it is highly essential that definite steps be taken by the radio industry to defend the threatened ether channels. Legislation tending to reduce broadcasting service should be vigorously opposed lest politicians, in their zeal for publicity, destroy the structure which has been so painfully built up. Fitting Receivers to the New Allocations IF THE new allocation structure survives the attack of self-seeking broadcasters and meddling politicians, it is likely to form the foundation upon which all future allocations will be based. A month's observation, under the new conditions brought about by the allocation, reveals an entirely new broadcasting world. In general, leading stations are now no longer marred by heterodyne whistles, with the consequence that their clarity of reproduction is greatly improved. On the other hand, in most localities, the number of points on the dial that near-by local stations are found has been reduced. This is the case particularly in the congested districts of New York and Chicago. In the wide gaps between the local stations, the listener with the moderate priced set is now served with good quality by stations several hundred miles distant. With a highly sensitive receiver, he can hear distant programs during the early evening hours as reliably as after midnight prior to the reallocation. These new reception conditions make those characteristics of receiver performance, paramount in the embryo days of broadcasting, once more of great value. For the last two or three years, we have been concerned principally with improved convenience in maintenance, secured by powering receivers directly from the light socket, and better tone quality, made doubly desirable b> the availability of high-powered, high-quality transmissions. Although progress in these directions is by no means halted, it now becomes increasingly desirable to encourage greater sensitiveness and better selectivity. Both these objectives were once attained by using regenerative receivers, the selectivity and sensitivity of which increase proportionately to the amount of regeneration employed. Fortunately, the regenerative receiver is no longer with us because a slight move of the dial, when it is in its most efficient operating condition, converts it into a transmitting station. But, even with several stages of tuned radio frequency, the best we can hope to do is to equal the selectivity obtainable with well-designed regenerative receivers. However, we cannot rely, in this day and age, upon regeneration. Regeneration sharpens tuning to the point that discrimination of audio as well as radio frequencies is obtained, so that either low or high tones are lost. This militates against the quality of reproduction, a characteristic no longc tolerated by the discriminating listener. We must, therefore, find new means of securing the degree of selectivity which has now become desirable and useful without sacrificing tone quality. This may be attained by the band-pass filter systems, admitting full energy of a ten-kilocycle channel band but discriminating sharply against any signals outside the desired channel. As progress is made in improving selectivity, the permissible power of broadcasting stations will increase greatly and consequently the listener may ultimately expect satisfactory programs on every dial position of his receiver. Furthermore, the number of stations which give him a clean signal, rising above local electrical noise and atmospheric disturbance, will increase in proportion to the power of the transmitting station. Forward looking manufacturers will take advantage of the opportunity which the new allocation brings by departing from stereotyped designs and producing receivers possessing new standards of selectivity and sensitivity. Aircraft Radio IN HIS annual report, Major General George S. Gibbs, Chief Signal Officer of the Army, announces the development of a new, double-voltage, direct-engine-driven generator, replacing the wind-driven dynamoter, hitherto used for powering transmitters and receivers. The motor-driven power source can be used while the plane is on the ground and is considerably more reliable than the wind-driven type. One of the principal problems with wind-driven generators was the requirement that automatic, self-regulating propellors, which compensated the variations in speed of the ship, are required to insure reasonably constant voltages. THE Bureau of Standards is improving its radio direction beacon by making it unidirectional. This will not only increase the beacon signal strength in the desired direction, but reduce the possibility of interference. A combination of vertical antenna with the two crossed coil antenna is used. Schedule of Broadcast Television Transmissions Call letters Location Wavelength No. of Holes in Disc Speed of Disc (ft. P. M.) No. of Pictures Per Second Schedule of Transmissions E. S. T* W2XAF Schenectady, N. Y. 31 5 24 1260 21 Tuesday 1 :30 p. m. W2XAD Schenectady, N. Y. 19.6 24 1260 21 Sunday 11:15-11:45 p. m. Tuesday, Thurs day, Friday 1:30-2:00 w3xk Washington, D. C. 16 . 7 48 900 15 P. M. Monday, Wednesday, Friday 8-9 P. M. WRNY New York City 326 48 450 5-10 minute periods every hour station is W2XAL New York City 32 48 450 on air W9XAA Chicago, 111. 61 48 900 15 10 to 11 a. m. Daily (wcfl) Chicago, 111. except Sunday WMAQ 447.5 45 900 15 Probably 11:30-12 p. m. Daily w4xa Memphis, Tenn. 24 900 15 Irregular (WBEC) wlXAY Lexington, Mass. 62 48 900 15 9:30 p. m. Daily (WLEX) w2xbu Beacon, N. Y. w8xav Pittsburgh, Pa. 63 5 60 900 15 Irregular w6xc Los Angeles, Calif. 66 36 1080 18 1:30 to 2:30 A. M. * As this issue goes to press the status of television on broadcast wavelengths is unsettled. The Commission has invited all interested parties to attend a meeting to discuss the advisability of allowing visual broadcasting within the band from 500 to 1500 kc. Also, the Commission has limited television transmission in this band to between the hours of 12 midnight and 6 a. m.