GE ApexPro TT, Technical Manual

Page: 77 / 192

Maintenance
2001989-351A ApexPro™ 4-15
505A
8. If the difference calculated in Determine frequency offset (step 18 ) is positive,
decrease the pot value by one. If the difference is negative, increase the pot value
by one. Type the command:
CAUTION
Do not move the pot setting by more than one value at a time to
prevent moving the intended set point/frequency too far, which
could cause signal dropout.
:35<space>X<space>1<space>Y
NOTE
X is the frequency band recorded in step 5 , Y is the pot value increased/
decreased by one (e.g. :35 1 1 156 )
9. Check the frequency on the spectrum analyzer. If it is not within 130 Hz of the
target frequency, repeat the steps in
Adjust T14 transmitter frequency .
10. Once the measured frequency is within 130 Hz of the target frequency the
calibration is complete. Record the total amount of Hz adjusted in the ApexPro
Telemetry Frequency Chart Reference Manual or somewhere it can be tracked
for the lifetime of the transmitter for future calibration reference.
Record the final pot value: _____________
11. Repeat step 8 to program the remaining bands to the same pot setting. (e.g. if
band 1 was set to 156, bands 0,2,3, and 4 should be set to 156).
Receiver calibration
Determine target frequency
NOTE
The Rohde & Schwarz FSH3 spectrum analyzer is used for the following steps. If
a different spectrum analyzer is being used, the detailed substeps may be
different.
1. Connect a serial cable between a laptop and the receiver subsystem Async
Comm connector.
2. Launch HyperTerminal .
3. Configure HyperTerminal to the following settings.