Garmin GDL 90 Installation Manual

Also see for GDL 90: Installation manual

Installation Procedures2-10 560-1049-00 Rev B GDL 90 Installation ManualThe Garmin AT UAT antenna is vertical polarized, optimized for UHF operation, and designed forinstallation in aircraft, including helicopters. The GDL 90 will receive signals from two antennas on topand bottom of the fuselage. Since UAT is a line-of-sight system, the antenna must have an unobstructedview of the target. Any “shadowing” or signal shading from the aircraft will degrade the performance.Shadowing may be from vertical stabilizers, wings, other antennas, engines, propellers, or the fuselageitself. Proper antenna location and installation is very important for the reception of the signals. See theUAT Antenna Installation Instructions, P/N 560-0215, for complete details.CAUTIONOperating the GDL 90 with no RF terminations on the Top or Bottom UAT Antennaports can result in equipment damage. Always operate the GDL 90 with the Top andBottom UAT Antenna ports terminated with a VSWR ratio of 3.0:1 or less.2.7 ELECTRICAL CONNECTIONSThe GDL 90 installation kit includes three D-sub connectors and three coax connectors. The connectorlayouts are shown in Figure 2-8. The D-sub connectors use the supplied crimp contacts as specified inTable 2-2. Make the crimp connections with the crimp tool specified.Table 2-2. Interface ConnectorsConnector Crimp ContactRef. Description P/N Description P/N DescriptionP1 I/O 162-1575 15 Pin D-Sub Receptacle 245-0027 20-24 AWG socket contactP2 I/O 162-1577 37 Pin D-Sub Receptacle 245-0027 20-24 AWG socket contactn/a Maint. Port 162-1574 9 Pin D-Sub Receptacle 245-0027 20-24 AWG socket contactP3 GPS antenna 162-0043 Coax connector, right angle N/A N/AP4 UAT ant (top) 162-0043 Coax connector, right angle N/A N/AP5 UAT ant (bot) 162-0043 Coax connector, right angle N/A N/AThe following table shows the specifications for the crimp contacts. Alternate crimp contact part numbersmay be used that are equivalent to those specified in the table below.Table 2-3. Crimp Contact SpecificationsGarmin AT Part Number 245-0027Description 20-24 AWG crimp socket contactColor bands Orange/Blue/GrayITT/Cannon P/N 031-1007-042Military number M39029/63-368