L band
The aircraft L-band ranges from 960–1215MHz. Aircraft can use Automatic dependent surveillance-broadcast (ADS-B) equipment at 1090 MHz to communicate position information to the ground as well as between them for traffic information and avoidance. The 1090 MHz frequency (paired with 1030 MHz) is also used by Mode S transponders, which ADS-B augments when operated at this frequency. The TCAS system also utilizes the 1030/1090MHz paired frequencies. ADS-B information can also be broadcast on the L band frequency of 978 MHz. DME and TACAN systems are also in this frequency band.