Maritime radio service in World War IIWhen the war began, public radio traffic was stopped. However, "Elbe-Weser Radio" continued to operate. Maritime distress service, which was run by the "German Maritime Rescue Association" in Bremen, experienced a great boost. As part of this maritime distress service, a mutual exchange of distress messages with the English radio stations remained common until the end of the war. Maritime distress messages that were broadcast by "Elbe-Weser Radio" with the introduction "CQ" (to all) were confirmed by "Cullercoats Radio" with the introduction "following received from". "Elbe-Weser Radio" operated in the same way. Elbe-Weser Radio was the only German coastal radio station to survive the war unscathed and was initially under the control of the Royal Navy. This ensured that the maritime distress service was maintained, not least for the safety of the ship's own ships. Effective help was also offered to some Allied supply boats that had got into distress in the German Bight. This ensured the continued existence of the Elbe-Weser Radio and the radio station was soon given additional civilian tasks.

Quelle:
https://second.wiki/wiki/elbe-weser_radio
http://www.seefunknetz.de/dac.htm