RD-18 receiver is mounted on antenna pole. RD-18 receives signal of the radiosonde, demodulates the signal, sends measured data to indoor PC by an Ethernet cable. RD-18 consumes less power and it is powered from PoE injector by an Ethernet cable. By selecting the PoE injector compatible with each country's power supply, it can be used in any power supply environment. RD-18 has backup capacitor inside, so it keeps working against momentary power failure. RD-18 also sends HK data (lock status, inside temperature and the status of power supply) to PC. RD-18 has other basic functions, such as antenna switcher, narrow 8ch band pass filter, AFC/MFC and real time spectrum measurement.