Radio Broadcast (Nov. 1925-Apr 1926)

328 RADIO BROADCAST JANUARY, 1926 THE ANTENNA AT STATION WHAZ remembered is the commemorative Joseph Henry broadcast, in honor of the American electrician and physicist, whose work in electromagnetism prepared the way for many later developments of the telegraph, telephone, and radio. Other educational broadcasts have found a place in the programs, including practical and non-technical talks by members of the faculty on subjects of current interest in the scientific and engineering field. Of course Rensselaer does not limit its radio activities to the operation of whaz on its frequency of 790 kc. (379.5 meters). As an engineering college in which electrical and communication engineering are among the major courses, the school employs numerous transmitting and receiving sets covering a very wide range of frequencies. Among the curiosities are a DeForest radiophone set which Professor Williams demonstrated to the students in his courses as long ago as 1910, and a Marconi wireless telegraph set dating back to 1902, containing one of the original coherers. Many radio amateurs both in this country and abroad are familiar with the call letters of the Rensselaer experimental stations, 2 xap, 2 sz, and 2 cdc. WIBO NEWSPAPER reports tell of an accident in the generator room of wibo in Chicago, when L. G. Rasmussen came into contact with a high tension wire during the evening program on September 17th, and was severely injured. He was taken to St. Francis Hospital in Evanston. The operator's injuries were sustained when the gold frame of his eyeglasses came into contact with a live lead. The frame of the glasses fused immediately and the resulting arc burned the face, hands, and chest, of the victim. The station had to be shut down before he could be released. This unfortunate occurrence should be a warning to other broadcast operators who have so far escaped. Familiarity breeds contempt, and men who handle high tension machinery every day are apt to forget that contact with it at the wrong time may prove fatal. Particularly with the higher powers and voltages which are coming into use in broadcasting, additional precautions are the order. One good trick is to work on the equipment, where possible, with only the right hand, leaving the left in the hip pocket on that side. The logic of that is the fact that if one is caught, the current will pass down the right side of the body to ground, instead of through the relatively low resistance arm-to-arm path which includes the heart region, the great splanchnic ganglion, and other primary nerve centers and organs. Secondly, never lay a hand heavily on a portion of a circuit which may be alive, without first flicking it lightly with one finger, which will give you a chance to disengage if there is anything wrong. The same precaution should be used in connecting two wires which may cause a short-circuit. Incidentally, the arc following a short circuit, if the potential difference is not too high, may be blown out with a puff of breath. Thirdly, every station should contain red fibre signs "Man working on this circuit — do not close," or some similar formula, to be attached to open switches when an operator is working on a "killed" circuit. These tags should be signed, and the rule is that no one but the man who attached the tag may remove it. Fourthly, keep away from the sets when there is a local lightning storm. And finally, all operators should be familiar with first-aid practice and methods of resuscitation, and in the larger stations it is a good thing to have a drill along these lines once a month. KFI ACCORDING to somewhat vague reports which have reached us, the engineers at kh have been experimenting with varying amounts of acoustic damping in the studio. They started, it seems, with the usual idea that a studio should be made as "dead'' as possible, the ideal studio being one with entire absence of reverberation. This opinion is now being modified, and the object of the experimentation at kfi is to ascertain how much reverberation is to be allowed for best results on the air. This quality seems to be like salt; you don't want much of it in the goulash, but a little is almost indispensable. KGO STATION kgo in San Francisco tackled a big job at the Municipal Auditorium, broadcasting the oratorio "Creation," given by the city of San Francisco with a chorus of 300, 65 players in the orchestra, and three soloists. This was possibly as big a pick-up undertaking as any one in the West has tried. There was also an organ, we must not forget to mention. The space occupied by the chorus and musicians was 48 by 80 feet, and the organ pipes rose 50 feet in the rear. The solution of the pick-up problem was found in the use of condenser microphones, which have no hiss or internal noise, when they are in proper working order, and can be used to pick up sounds within an extreme range of volume. One of these mechanisms, about three inches in diameter and ten inches long, was suspended twenty feet over the heads of the performers, carrying most of the orchestral and choral tone. A second condenser was used for the soloists, about five feet in front HIGH TENSION EQUIPMENT . . HANDLED GINGERLY ' MUST BE