Radio broadcast .. (1922-30)

262 Radio Broadcast efficient in the original detection of signals. However, in succeeding steps of amplification, the impulses become stronger and stronger, and are capable of controlling a more powerful stream of electrons, or plate current, than was possible before, due to the inertia of the electron. (Inertia is a quality possessed by everything having mass, which resists any attempt to vary its relative state of motion.) The idea will be made more clear by analogy. It is an easy matter for a ball player to catch a baseball traveling fifty feet a second, but it would require a giant (no pun intended), comparable to a larger grid impulse, to control or stop a cannon ball moving at the same velocity! Thus a higher plate potential, which in part determines the strength of the electron flow, may be applied to the plates of successive steps of amplification, with a correspondingly greater response in the receivers or loud speaker. Working back to the differentiation between detector and amplifying tubes, it is necessary to evacuate the bulb more completely when a heavier current is to be passed through it, owing to the fact that the partly gaseous content of a low-vacuum tube would be ionized by the electron stream. lonization is the breaking up of the atoms of gas into their component positive and negative charges, a condition which is indicated by a blue or purple haze surrounding the elements of the tube, and which greatly affects the negative charges, electrons, given off by the filament, generally rendering the tube inoperative. A very interesting example of ionization in a partial vacuum is the northern lights or Aurora Borealis. This phenomenon is caused by the passage of electrons thrown off by the sun, through the rarified upper strata of the polar atmosphere, where they are apparently concentrated by the earth's magnetism. SUPPLEMENTAL LIST OF BROADCASTING STATIONS IN THE UNITED STATES FROM OCTOBER 6 TO NOVEMBER 22 INCLUSIVE CALL SIGNAL OPERATED AND CONTROLLED BY WAVE LENGTH KFCK Colorado Springs Radio Co KFDC Radio Supply Co.' KFED Billings Polytechnic Institute . . . KFFA Dr. R. O. Shelton KFGH Leland Stanford University KYQ Electric Shop WNAQ Charleston Radio Electric Co. ... WNAV People's Telep. & Teleg. Co. ... WNAW Peninsular Radio Club WNAX Dakota Radio Apparatus Co. WNAY Ship Owners Radio Service .... WOAF Tyler Commercial College .... WOAH Palmetto Radio Corp WOAJ Ervins Electrical Co WOAK Collins Hardware Co . WOAL William E. Woods WOAM Arthur F. Breisch (temporary-i day) . WO AN Vaughn Conservatory of Music WOAO Lyradion Mfg. Co WPAC Donaldson Radio Co WPAD W. A. Wieboldt & Co WPAL Superior Radio & Telep. Equipment Co. WPAM Auerbach & Guettel WRAA Rice Institute WRAY Radio Sales Corp WTAC Penn. Traffic Co WTAU Ruegg Battery & Electric Co. ... Colorado Springs, Colo. . . . 360 Spokane, Wash 360 Polytechnic, Mont 360 San Diego, Calif 360 Stanford University, Calif. . . . 360 Honolulu, Hawaii 360 Charleston, S. C 360 Knoxville, Tenn 360 Fort Monroe, Va 360 Yankton, S. Dak 360 Baltimore, Md. 360 Tyler, Tex 360 Charleston, S. C 360 Parsons, Kans 360 Frankfort, Ky 360 Webster Groves, Mo 360 Bethlehem, Pa 360 Lawrenceburg, Tenn 360 Mishawaka, Ind 360 Okmulgee, Okla. Chicago, 111. . Columbus, Ohio Topeka, Kans. Houston, Tex. Scranton, Pa. 360 360 360 360 360 360 Johnstown, Pa 360 Tecumseh, Nebr 360 What Would You Like to Have in Radio Broadcast? The editors would be pleased to hear from readers of the magazine on the following (or other) topics: 1. The kind of article, or diagram, or explanation, or improvement you would like to see in RADIO BROADCAST. 2. What has interested you most, and what least, in the numbers you have read so far.