3-8. ADS-B Antenna Interface. The aircraft ADS-B antenna is an important part of the overall
ADS-B Out system because antenna systems are major contributors to the system link
performance. The location and number of antennas required for the airborne ADS-B Out system
is a function of the equipment class of the selected broadcast link (UAT or 1090ES). Single
bottom-mounted antenna (TSO-C166b and TSO-C154c A1S and B1S classes) installations are
allowed. For the UAT link, 16-watts minimum transmit power at the antenna output is required.
For the 1090ES link, 125 watts minimum transmit power at the antenna output is required