The effect of wave damping in radio direction-finding

Abstract

For the use of ships fitted with radio direction-finders, schemes for the provision of beacon transmitting-stations are being inaugurated in various parts of the world. In order to minimize interference it is evidently desirable that these beacons shall work on undamped or modulated undamped waves, and confidence in the accuracy of direction-finding when using these waves must accordingly be inspired in those who will make use of this application of wireless for navigation purposes. The present paper summarizes the hitherto published knowledge on the relative advantages of damped and undamped waves for accurate direction-finding, and then describes some special experiments which have been carried out in this country on this particular point. It is concluded that when direction-finding is employed at such times and under conditions which are known to produce the well-known “night effects” of variable errors in bearings and broad signal minima, these effects are equally likely on damped and undamped waves. Since the conditions under which direction-finding is accurate enough for marine navigation purposes at all times are now well known to be connected only with the distance of transmission over land and sea, it is to be inferred that the type of transmitted wave is immaterial to the accuracy, and that continuous waves, whether modulated or not, may in future be used with perfect confidence in all cases in which the damped waves from spark transmitters have given satisfactory results.