Garmin GTS 825 Pilots Guide - Page 9

GTS 800 The GTS 800 is a TAS system that can track up to 45 Mode A/C/S targets, and display up to 30 intruder threats at a time, depending on the display being utilized. Offering 40 watts of transmit power, a ±10,000 foot vertical separation maximum, and an active interrogation range of up to 12 NM in the forward direction, the GTS 800 system will interface with a variety of compatible system displays in the cockpit. GTS 820 The GTS 820 is a TAS system that can track up to 45 intruding aircraft equipped with Mode A/C transponders, and up to 30 intruders equipped with Mode S transponders. A GTS 820 TAS has an active surveillance range of up to 40 NM in the forward direction, dependent upon interference limiting techniques based on the number of TCAS II interrogators in the area. Interrogation power and range in the left, right, and aft quadrants is reduced in a manner similar to TCAS II systems. It includes a GPA 65 PA/LNA Module that is remotely installed near the top directional antenna to boost the interrogation range. GTS 850 The GTS 850 is a fully compliant TCAS I certified system. Operational capabilities are similar for airborne traffic surveillance for both the GTS 820 and GTS 850 systems. Antennas General Antenna Information A top-mounted directional antenna is used to derive bearing to the intruder aircraft. Top antenna transmitted interrogations are directional, reducing the number of transponders that receive the interrogation thus reducing potential garble on the 1090 MHz band. Optional bottom monopole or directional antenna transmit interrogations are omnidirectional. Intruder bearing can be determined from the top directional antenna or an optional bottom directional antenna for retractable gear aircraft. 190-00587-02 Rev. A Garmin GTS 8XX Series Traffic Advisory System 5