Bearing signals

[Sailor Steve]

The radio compass and radio fog signal for the first time give the navigator a means of taking accurate bearings of fixed points or of other vessels, regardless of fog or weather conditions, and at much greater distances than are possible for sight bearings even in clear weather.

From Engineering, by G.R. Putnam, 1924.

http://www.pnas.org/content/10/6/211.full.pdf

A constant signal is sent for the other ship to home in on, very much like modern navigation stations.