The invention discloses a radar system (100) for the detection of low RCS-objects (110, 140, 150, 160, 190) such as forest fires, said system comprising a first plurality of stations (120) for transmitting radar energy, said stations having mechanically fixed antennas (220), and a second plurality of receive stations (130) for receiving reflections of radar energy transmitted from the transmit stations, said stations having mechanically fixed antennas (220). The antennas (220) of said transmit and receive stations have a main beam (221) which is essentially parallel to the ground, and at least a sub-set of the receive stations is equipped with means for recording a first and a second received signal, and means for subtracting one of said signals from the other of said signals. Said transmit and receive stations are arranged to function within the frequency range of 10-100 MHz.