Radio Broadcast (May-Oct 1922)

194 Radio Broadcast distress call of sinking vessels, or aeroplanes stalled in inaccessible places, or adventurous explorers who have encountered difficulties which make it imperative that they get help. Besides these cases, in which the reception of perhaps one millionth of a watt of power from the distressed operator means the difference between life and death, there are other cases where radio means the bringing to life of some people leading an existence so lonely that they are dead in so far as contact with other human beings is concerned. To the dweller on a lonely isle, perhaps in connection with the rest of the world only once a year, to the lonely watchers on the lighthouses and lightships, for weeks and months at a time abandoned to the wind and waves, radio telephony offers something of almost inestimable value. They can now hear the voice of their fellow man perhaps every evening, and the music which travels to them so silently and swiftly must put new life into their monotonous existences. There must be many islands on our coast where the installation of a radio outfit will bring lonely people into immediate touch with the rest of the human race. In such places, and in the lighthouses and ships, radio broadcast entertainment will bring cheer and enjoyment where nothing else avails. In a recent interview, George R. Putnam, Commissioner of Lighthouses, reported that many of the lighthouses in Alaska are being equipped with radio telephone apparatus. In some of these stations, he states, the keepers have been without mail from the outside world for as much as ten months. In hospitals a receiving outfit should be a wonderful help in keeping patients interested and comfortable. Furnished with a series of head sets, so that any patient may listen in or not, as he desires, a good receiving outfit would prove a valuable adjunct to the cheerful nurse in keeping a ward filled with smiles and contentment. At the sea-shore or away in the mountains it is now possible to be in almost constant communication with the city. This portable radio set has a receiving range of several hundred miles and a transmitting range of four or five miles Not all of us have the vision and imagination of a Faraday, so that there are still some details of radio theory which seem more or less obscure. One of the developments of radio, which seems always to attract much attention, is the reception of radio signals by a set on a moving object, such as train, bus, aeroplane, etc. Now there is really nothing strange about this at all; in fact, it would be much more strange if signals were not received on a moving car just as well as when it is stationary. Radio communication is carried on by means of disturbances — wave motions — in the ether; these waves travel with the speed of light (186,000 miles per second) for the very good reason that they are really the same thing as light. If we grant that a loo-meter radio wave is the same kind of a thing as a 10,ooo-meter wave, then radio and light are the same thing; because of the electric and magnetic fields associated with them, they are called electromagnetic waves. When an electromagnetic wave travels by an antenna, it sets up alternating currents therein, which, acting on detector and telephones, give an audible signal. Now, will it make any difference whether the receiving station is moving or not? Radio waves being the same kind of disturbance as light waves, we may argue the question from the action of light. If a man in a passenger car, moving through a station, watches some one on the platform light a match, will the color and intensity of the flame be the same as if the car was not moving but was stationary at the platform? The flame corresponds to the transmitting station of a radio set and the observer's eye receiving the electromagnetic waves from the flame, corresponds to detector and telephone. The answer to the question is evidently — Yes, the motion of the observer does not in the least interfere with the observer's eye perceiving the