Broadcasting suitcase belonging to secret agent Sjoerd Sjoerdsma 

Germans could receive broadcasting signals and trace their origins. So transmission stations were set up within densely developed cities and evacuated after 30 minutes. This was made easier by the small broadcasting cases brought along by the secret agents who had been parachuted in. 

Reports
Information was also smuggled into England. Various espionage groups gathered data on the German army. They made reports that were translated into secret code and telegraphed to England.

Improve contacts
Sometimes the reports were recorded on microfilm and taken to England via escape routes. Secret agents were parachuted into the Netherlands to try to improve spy contacts.