User's Guide Part 2

Test link end hardware Chapter 7 Troubleshooting
phn-0896_009v003
7-16
UNDER DEVELOPMENT
Feb 2010
Test UltraSync GPS receiver
The UltraSync GPS synchronization unit, if installed, is located between the ODU and
the LPU (Figure 2-17 an
d Figure 2-18). Use the status LEDs (Figure 7-5) to test the
GPS unit.
Figure 7-5 GPS synchronization unit
To troubleshoot the GPS synchronization unit, perform the following test procedure:
Power supply: Check that the +3.3V and RF_ON LEDs are lit, indicating that the
GPS is receiving power. If they are not lit, confirm that all link end hardware (PIDU
Plus, LPU, ODU and cabling) tests have been performed.
Synchronization: Approximately 2 minutes after powering on, the GPS_FIX LED
should be lit. If it is not, ensure the GPS is at a height of at least 1.8m above the
ground, where there is an unobstructed path to the sky.
Timing: When the GPS_FIX LED lights up, the PPS_OUT LED should begin blinking
faintly at one pulse per second, indicating that sync is being generated. If does not,
replace or repair the GPS synchronization unit.