Intersystem interference analysis on track vehicle 309 - evaluation of interference risk from computers on the vehicle

On assignment from FMV, FOI has performed intersystem-interference analysis on track vehicle 309, where co-located electric equipment can inter-fere with installed radio systems. The analysis has been performed on the used frequency bands for the radio systems, Ra180, Tetra, IGR and TDRS-A. Also, a measurement campaign to investigate the losses in between a com-puter placed inside the vehicle to the radio system antenna placed outside the platform, has been performed. The purpose has been to achieve good accuracy in the intersystem-interference analysis for the analysis made on track vehicle 309. The losses have been measured for several antenna con-figurations on the roof and also when shutters or doors are open. The vehicles examined are track vehicle 309, Galten and the combat vehicle 9040 at frequency bands 30-88 and 225-400 MHz. From the intersystem-interference analysis we can conclude that to avoid significant deterioration of the radio system performance or the possible communication distance, the computer has to meet the RE102 in MIL-STD-461 emission requirements. Also, if a computer tangents the civil emission standard EN55022 Class B or equals the measured computer in our model, it is very difficult to achieve adequate shielding. If such computer is used, we expect a significantly reduced communication distance for the co-located radio systems.