true, although if it was true,
wouldn't they be able to locate them easier?
I mean if more than one ship got the same signal, surly they could use it to locate a sub?
Yip they had direction finders in those days
Direction finder | Radio Navigation & Radio Direction Finding | Britannica
Direction finder, radio receiver and antenna system for determining the direction of the source of a radio signal. A direction finder (DF) can be used by an aircraft or ship as a navigational aid. This is accomplished by measuring the direction (bearing) of at least two transmitters whose locations