A helicopter borne radar concept for RCS measurement and ECM evaluation has been constructed. It was tested during one flight mission when the RCS of a combat boat was measured. Tests show that the chosen technique works, and should be possible for a full-scale system. To realize an advance system like this, with limited resources, one must reuse components from other systems. Most of the RF-subsystems was borrowed from FOI radar measurement system ARKEN. The gyro stabilized antenna gimbal was reused from the SMU system. Some power systems were converted to the helicopter 24 volt dc current. HMI (Human Machine Interface) was redesigned to a two operator system and adopted to RCS measurement. One of the main concerns was if the coherency of the land based system Arken could be maintained in the vibrating environment in a helicopter. Analysis of data show that the helicopter borne system works with good coherency.