Hello!
It could be HF (High Frequency) transmitter, but they had few very good HF transmitters in the vicinity, like Kootwijk, Borkum, Norddeich and Kiel, so I am not sure it was "ordinary" HF transmitter, but I am not sure, of course.
There were many intercept radio stations of German Navy radio intelligence service, B-Dienst. And, the each station had its own DF (direction finding) sub-stations.
For example, one of the stations was in Castle Terlinden just outside the village of Sint Andries near Bruges, Belgium and it was connected with DF stations at Ostends, Belgium; Maasluis, Holland, and Le Touquet, France. It is just one example! And the all DF stations had their own sub-stations.
They also had experimental stations for radar, and they also had stations for reconnaissance of the enemy radar signals...
Perhaps it was kind of dislocated command place of the German navy, or kind of regional command place? In that case they had HF radio communication, of course.
The Germans had excellent radio networks. The networks were named (mainly) by the world's region, it was coastal network, for the U-boats in the Biscay and the North Sea, network Ireland for the central Atlantic, America for the western Atlantic, Africa for the Indian ocean etc etc. They also had networks for convoy operations, Diana and Hubertus, used by the wolfpacks which attacked particular convoy...

The each network (circuit, in American and British documents) consisted of few HF frequency bands, 4, 8, 12, 16 MHz, and one VLF frequency. because I think you are radio amateur, I think you understand why they used different bands (during a day) in one network.

Hope I helped at least a little.
Best regards!
Funkmeister