What is ATC? The ATC Transponder system is sometimes called Secondary Surveillance Radar (SSR).

It is a secondary radar system designed to automatically give Air Traffic Control (ATC) information.

ATC Information The information obtainable from the system is: -

• Range & Bearing• Identity• Altitude

SSR Aerial

PSR Aerial

ATC System • Mode A – Identity

• Mode C – Altitude reporting

ATC Block Diagram

OPERATION

ATC Aerials

ATC utilises an L-band aerial mounted on the bottom of the aircraft.Received centre frequency is 1030 MHz.Transmitted centre frequency is 1090 MHz.Transmits an omni-directional vertically polarised signal.

ATC Testing- Check the manual- Remove the Arial- Co-Axial TDR Test - Test the system (ATC-600A)