Garmin GTS 855 - Manual (Page 9)

5 190-00587-02 Rev. A Garmin GTS 8XX Series Traffic Advisory System
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.