Radio broadcast .. (1922-30)

RADIO BROADCAST 103 may be transmitting distress signals or which desires to learn its position. (3) Its use on aircraft for enabling the pilot to tell the direction to a landing field. It is often impossible to see the ground from airplanes which are carrying mail or which are engaged in commercial business and must, therefore, fly under all weather conditions. The pilots of airplanes are always anxious to know the exact direction to the closest landing field in order that they may come safely to the ground in case of need. (4) Its use on the ground at landing fields for aircraft to tell the direction of aircraft in flight which have on board radio transmitting equipment. (5) Its use at a station engaged in ordinary radio communication. Such use takes advantage of the fact that transmitting stations in one direction produce very weak signals, while transmitting stations in another direction may be heard very clearly. (6) Its use as the antenna of a small portable receiving station, such as may be carried in an automobile or by hand. For all of these uses it is important to know whether the direction finder is accurate in its indications. A calibration can be made which, when applied to the readings of the direction finder, makes its use entirely practical. Such a study of the accuracy of a radio direction finder has been conducted by the United States Bureau of Standards of the Department of Commerce. The radio engineers connected with the radio laboratory of the Bureau of Standards have conducted a series of experiments to determine what kinds of objects cause serious change in the Radio direction finder in use in obtaining exact position of passing radio waves. The observer turns the frame by means of cords in order to be sure that his body has no effect on the direction of the waves. The detector and batteries are seen on the stool near the operator