There are thousands of people bathing along a beach stretching over several kilometres. The weather, dangerous currents, jellyfish and predatory fish can put people at risk in the water and on the beach. In order to notify people quickly and safely when they are in danger and what the danger comprises, fixed stations along the entire beach indicate the current situation with boards, lights and audio signals. The SHR-12 L4 wireless receiver with BNC connection option and an external antenna and the SHT-12 BS transmitter are behind all of this. The long range of up to 4.5 km is achieved by the installation of several SH-12 RP repeaters. These are positioned in series and can therefore cover this long range easily.