into consideration these additional synchronization values or quality the accuracy of an evaluation can thus be further improved for a real radio coverage in this way a sufficient overlapping of the radio cells or radio areas within a multicellular mobile radio system can be determined or checked very precisely in order to initiate suitable countermeasures where necessary since the evaluation unit preferably controls the base stations automatically and the measured field strength data which can also feature the previously mentioned synchronicity values is also automatically evaluated significant cost savings are produced in the detection of the radio field illumination or radio field coverage of a multicellular mobile radio system for further improvement and especially for detecting changes in the radio coverage for example caused by constructional measures within a building or an expansion of the mobile radio system the detection of the mobile radio system can also be undertaken at predetermined regular or irregular intervals with a current evaluation result being compared with at least one previous evaluation result in this way changes in the radio coverage as produced at regular intervals by constructional measures can be detected in good time and corresponding countermeasures initiated furthermore the measured field strength data as is usual with dect can also feature a base station identifier this type of base station identifier is for example the so called rfpi radio fixed part identity value which is 40 bits in length according to the dect standard in u201c private multiple cells u201d ariclass b the lower 8 bits in this case define the number maximum 255 of base stations or u201c fixed parts u201d in dect mobile radio systems with more than 255 base stations base stations with the same rfpi value may thus not overlap in radio terms a mobile unit would.