Radio Broadcast (Nov. 1925-Apr 1926)

330 RADIO BROADCAST JANUARY, 1926 refer to wave "filters" — networks of resistance, inductance, and capacity which allow only a certain "band" of frequencies to pass. But we are also familiar with wave "traps," used to eliminate a narrow range of frequencies, and here apparently we think of the wave as a small animal — a rat or mouse — while when we speak of "carrier" waves or "carrier" telephony the wave has become a beast of burden. The term "trap," incidentally, is one of those ubiquitous comparisons which can be found in almost every trade; the bend in a drainpipe to prevent gases coming back along the tube is called a "trap" by plumbers, for example. The "regeneration" of Armstrong is a distinctly figurative term, carrying a theological connotation, although it was used in connection with gas engines and other prime movers long before the vacuum tube was invented. There is also a physiological reference in the name "tickler" applied to a "feed-back" inductance in the plate lead of the amplifier-rectifier tube of a receiving set. The early Workers in this field must have been struck by the extraordinary increase in volume as the tickler coupling was brought up, and the sudden break into oscillation; and they compared these phenomena to the peculiar spasmodic reactions of human beings to a tickling stimulus. Nor must we overlook the word "feed-back" in this connection. Why should we speak of the oscillations in the plate circuit as being "fed" back to the grid, instead of merely saying "brought" back? This figure has a practically universal utility. It is used in transportation, in reference to railroads and waterways, as, the Morris Canal Feeder. In communication, as "feeder" telegraph offices. In electrical engineering — "feeder" conductors, generating stations, etc. In sport: basketball players speak of "feeding" a team-mate when he is in position to shoot for the goal. And it is all based on the nutritional instinct, of course, and the comparison is widespread because that instinct is shared by all living creatures. It is hardly possible to go through the list of metaphorical expressions which have invaded the radio field, but a few more typical ones may be mentioned briefly. Electricians talk of "juice," apparently a survival of the early fluid theories of electricity. The flow of high frequency oscillations on the surface of a conductor is called "skin-effect." Irregular interference of arc transmitters on low wavelengths is termed "arc-mush." Transient interference with radio reception, both natural, as from lightning, and artificial, as from arc lamps, lightning circuit grounds, sparking commutators, etc. is referred to as "strays." We talk of "shielding" a panel with metal. Spark interference is "jamming," a graphic expression which originated in the English Channel, although familiar in a related sense to the riders in the New York City subways during the rush hours. (7*o Be Continued) Memoirs of a Radio Engineer, VIII IN OUR last issue I gave a brief account of the Titanic tragedy of 1912. For some days after the disaster all was confusion. Commercial stations and ships interfered with each other, some of the amateurs, it was charged, interfered with commercial stations, and no reliable list of survivors could be obtained. As the Carpatbia neared New York with the survivors, communication improved, and the names came through in the rescue ship's mournful 60cycle spark. Most of the shore copying was done, I believe, by the Wanamaker station, whi. The amateurs shut down voluntarily, setting a good example which they have followed on other occasions since that time, although now, with commercial and amateur wavelengths so far separated, the necessity for it has disappeared as far as sos calls are concerned. They listened on their double-slide tuners and loose couplers to the long fateful strings of names. The commercial operators worked heroically, some of them standing continuous watches until they were ready to drop. 1 have referred before to the anarchy which prevailed in the ether lanes in those days. Everybody transmitted on any wavelength which pleased him, or, for that matter, without knowing what his wavelength was or giving any signs that he cared. Amateurs interfered with paid commercial traffic, and refused to shut down when sworn at in code. Profanity on the air was the rule rather than the exception. The caution of Y. M. C. A. broadcasting phraseology was as yet unknown. Call letters were self-assigned, according to fancy; initials were used, or simply what was known as a "good" call — one that had a pleasing rhythm and lilt to it in the Continental or American Morse code. Both codes were used, with American Morse as yet more prevalent. The Britishers used Continental, and there was a strong prejudice against it among the Americans. Morse, with its spaced letters, such as c (two dots, space, dot) was harder to copy than Continental, but faster, and the Morse operators were very contemptuous of the newer symbols. The New York Herald, which maintained a wireless station, ohx, in connection with its excellent shipping news department, sent press every night at 9 o'clock, first in Morse, then in Continental, but traffic was generally sent in Morse, and my recollection is that the election returns of November. 1912, were sent in Morse only. All this confusion could not last. Soon after the Titanic catastrophe, the government took hold. In 1910 a law had already been passed providing for radio equipment on certain steamers. This was not taken very seriously until 1 9 1 2, when it was amended to apply to all vessels licensed to carry fifty or more persons on the ocean or the Great Lakes, and to provide for auxiliary apparatus covering failure of the main set, continuous watches, and penalties in case of failure to observe the law. A little later, on August 13, 1912, the Senate and House of Representatives passed "An Act to Regulate Radio Communication," under which the present licensing system for stations and operators was instituted. By an international convention signed at London on July 5, 19 12, and ratified by the United States Senate early in 1913, initial call letters were allocated to the several nations. Those two years, 1912 and 1913, were the great legislative years of radio. In fact, so much legislation went through that this country has not experienced any since! and has gone twelve years without altering the radio laws themselves. What adjustments have been made the Department of Commerce has taken care of by regulations under the administrative power which it was granted by the law of August, 1912. These momentous changes percolated down to even the lowest strata of amateurs. Some of my friends lost their call letters. Such amateur calls as mhs, nse, dse, su, jr, ay and, yf, became taboo. M calls belonged to British stations; D was allocated to the Germans; N to the American Navy. Amateurs were to be licensed, and to receive calls beginning with numbers, denoting the radio district in which the applicant happened to find himself. All stations, from the largest down to the most insignificant which might interfere with reception over a State line (the necessary limitation of Federal authority), were subject to the new regime. It was like the lines in the Agamemnon: None who was mighty then, and none so smalt But in the sack of doom is borne away. All the amateurs, formerly so reckless and carefree, went about with worried faces, wondering if they could pass the examination, and trembling in fear of a new ogre, the Radio Inspector. {To be Continued) THE AMATEURS OGRE . . . TREMBLED BEFORE A NEW -THE RADIO INSPECTOR"