Radio Broadcast (May 1928-Apr 1929)

THE PANEL OF THE 5-METER RECEIVER A top view of this receiver is shown in Fig 1. At the left is the tuning condenser, of the vernier driven type. The knob in the center of the panel is the regeneration control. At the right is the filament rheostat What About the 5 -Meter Band? By R. S. Krase THERE has been too much sorrowing for the Ishmaelites, those chaps who fell out with the community and took to the hills where there were better chances of running away — and more things to run from. I suspect that in the course of hunting and being hunted they fell across more interesting things per month than their orderly relatives down in the towns saw during a lifetime. This is of course an argument for crime and disorder, which is quite fitting, since we are about to tell a story of some wholly irregular proceedings that resulted in driving a surprising lot of interesting radio rabbits out of the electric brush. HOW IT BEGAN f~\ F COURSE there isn't anything novel about the 5-meter wave except by reason of its having so long lain in mothballs with all the other short waves that the early radio men from Hertz to Marconi investigated. The spark apparatus then available not being very suitable for short-wave work, not a great deal was learned, and the styles turned toward long waves with antennas large enough to cover a Texas county. When the vacuum tube had become thoroughly practical as a transmitting device we were treated to the singular show of a world full of radio folks stoutly insisting that a vacuum tube was useless on all waves below 400 meters — but that it was of small moment, since the waves below 3 50 were worthless anyway. At this statement a number of us went off the reservation just as the Indians used to and after some bushwhacking around we discovered that the short waves were not worthless but looked astonishingly as if they might be improvements on the longer waves. Furthermore, we found that the vacuum tube oscillated nimbly at 60 meters, whereas our spark sets refused to get down to 150 at all. This was duly denounced as rank heresy by the orthodox, who took no part whatever in such practices, i.e., making circuits that would oscillate at 60 meters. So it went, even as late as 192 1. Sprinklings of stations below 200 there were, but at least one of us (which was I) was hauled before the radio club and accused of communicating with an imaginary station because I and the station I was working were both on 160 meters, and the MANY years ago, when there was no radio hut telegraphic radio, we used to talk to station gLQ, at Lawrence Kansas. Not so many years ago we met the operator of this station, who was then at Cruft Laboratory working with John Hays Hammond on the various secret radio transmission systems in which the inventor was interested. Together we listened with considerable awe to lectures on tubes, etc., from Professors Pierce and Chaffee. Since then, we have known Kruse intimately through his breezy articles in QST. Now, we are glad to say that Mr. Kruse will be a regular contributor to Radio Broadcast. He will speak about short-wave receivers, transmitters, antenna systems, laws, problems — and all that goes with them. An article to follow this one will give the constructional data on the 5-meler receivers and transmitters described in this article. If there is any reader of Radio Broadcast who does not know Kruse already, he is hereby introduced ! — The Editor. accuser, being nearby, could hear my part of the proceedings but not the other fellow. Of the commercial folks our good friend Grebe first showed faith by building a tuned r.f. amplifier that went down to 150 meters! Grebe shows his continued faith in short waves by continuing to build receivers for the very high frequencies. By 1923 we had become fed up with this sort of thing, and through the machinations of Boyd Phelps and myself, some amateur stations staged an "Exploring 100 Meters" Party, moving our transmitters down by steps and demonstrating that signals would really come through at such wavelengths as 60 meters. There was loud derision at first — and puzzled silence afterward — for the signals had of course come through like the well-known ton of bricks just as several years of tinkering had assured us they would. The tinkering was, by the way, started by Phelps at least as early as 19 19 with a low-power 33-meter spark set. After that many names appear that all amateurs know — Reinartz, Dunmore, Conrad, Ramsay. Presently, there was a short-wave "CQ Party" and many stations were heard over great distances. However, the great congregation remained at the old waves — mainly a little above 200 meters. It is very singular that all the wavemeter errors were upward! Presently, the Washington Radio club produced some active 100-meter stations, those of Browne, Darne, Basim and Hastings in particular. Soon we managed to blast out of the authors some articles on short-wave tuners. These tuned all the way down to 90 meters and Schnell's went to 60 even. Things now became active — there were investigations between the Naval Research Laboratory and other stations, under the leadership of Dr. A. H. Taylor and L. C. Young. Then a cooperative arrangement with Leon Deloy of Nice, France, put our own Schnell's 100meter signal across the Atlantic and then Deloy's came back. A few hours later Reinartz talked to Deloy and then many others did it. Presently, in 1924, the Department of Commerce gave back again to the amateurs some of the territory below 150 meters, which resulted in the present system of amateur wavebands and the pages of QST bristling with articles on using them. The population, however, howled murder and refused utterly to use the low waves until there was much more demonstration by Schnell and others that the 40 and 80-meter bands were good ones. At that the 20-meter band lay idle until the Experimenter's Section of the American Radio Relay League made 20-meter tests resulting in daylight transcontinental contact between Reinartz on the East Coast and Willis on the Pacific. SETTLING UP BY THIS time the 80-meter band was settled territory and presently the40-meter band became the same. Nowadays, the 20-meter band is thickly populated. Long ago, however, the ones who discovered the 20, 40, and 80-meter bands have moved on down to 5 meters and have run assorted tests with uniform results — oh, very uniform! Without exception there have been no signals but those of Uncle Henry's model T ignition systems. From this it is clear that there is nothing to this 5-meter business, especially since the latest and most up-to-date transmission theory points out clearly that wavelengths of the order of 5 meters will never come 212