scope:

The present document states the minimum performance requirements for radio transmitters, receivers and transceivers at ground-based aeronautical stations operating in the VHF band (118 MHz to 136,975 MHz) allocated to the aeronautical mobile service. In situations where transmitters and receivers are located in close proximity there is the possibility of interference. In such cases, external filters and isolators may be necessary as part of the installation to achieve an isolation performance in excess of the minima defined in the present document to overcome the interference.