Comm Antenna Installation Check (Gnc 300Xl) - Garmin GPS 155XL Installation Manual

3.11

COMM ANTENNA INSTALLATION CHECK (GNC 300XL)

Check for insertion loss and VSWR. VSWR should be checked with an in-line type wattmeter inserted in the coaxial
transmission line between the transceiver and the antenna. Any problem with the antenna installation will most likely
be seen as a high reflected power. A VSWR of 3:1 will result in a 25% loss in power.
9 8 7
18 17 16
26 25
Figure 3-3. View of J102 Connector From Back of Rack
J101 PIN
1 RESERVED
2 MIC AUDIO HI (GNC 300XL)
3 MIC AUDIO LO (GNC 300XL)
4 MIC KEY (GNC 300XL)
5 COMM AUDIO HI (GNC 300XL)
6 COMM AUDIO LO (GNC 300XL)
7 RESERVED
8 MIC INTERCOM (GNC 300XL)
9 RESERVED
10 REMOTE TRANSFER (GNC 300XL)
11 RESERVED
12 TRANSMIT INTERLOCK (GNC 300XL)
13 SEQUENCE HOLD LOW
14 ALTITUDE D4
15 ALTITUDE A1
16 ALTITUDE A2
17 ALTITUDE A4
18 ALTITUDE B1
19 ALTITUDE B2
20 ALTITUDE B4
21 ALTITUDE C1
22 ALTITUDE C2
23 ALTITUDE C4
24 ALTITUDE COMMON
25 GROUND
26 REMOTE ENTER
Table 3-3. J102 Pin Functions
6 5 4 3 2 1
15 14 13 12 11 10
24 23 22 21 20 19
PIN FUNCTION
GPS 155XL/GNC 300XL Installation Manual
P/N 190-00067-22 Rev E Page 3-8