Spectrum Management for Radio Astronomy

Radio Frequency Interference (RFI) are disturbances generated by a non-celestial source within a radio telescope's observed frequency band. This includes telecommunications, satellite communications, electrical equipment, Wi-Fi, etc. RFI is a major issue in radio astronomy as RFI are usually many orders of magnitude stronger than astronomical signals. Therefore, proper spectrum management has to be done. Regulations are enforced to protect very important frequencies e.g. 21-cm HI line. However, not all frequency bands can be protected especially if the telescopes have large bandwidths. In this case, RFI mitigation methods such as zapping has to be implemented. 

Radio Quiet Zones (RQZ) are ideal zones where radio transmissions are restricted to protect a radio telescope from RFI. RQZs have to be established in order for radio telescopes to be built, and this requires thorough research of the area in terms of telecommunications, population density, humidity factors, land topography, aircraft traffic, and many more. Regulations regarding RFI are usually enforced stricter in this regions, with spectral management and power flux-density limitations. Radio Notification Zones (RNZ) on the other hand are more realistic zones to implement less strict regulations (only certain frequency bands are prohibited). In the case of Malaysia, the RQZ and RNZ that has been determined are Kuala Tembeling and Jelebu respectively.