Adjusting Frequency - Codan NGT 2010 RF Technical & Service Manual

Adjusting frequency

Drawing
ALTERNATIVE TEXT
NOTE
All the channels are synthesised and locked to the 44.545 MHz reference crystal
oscillator Z401.
To adjust the frequency:
NOTE
1
1
1
1
1
Drawing
ALTERNATIVE TEXT
NOTE
NOTE
All the channels are synthesised and locked to the 14.848333 MHz reference crystal
oscillator Z1.
To adjust the frequency:
NOTE
1
1
1
1
1
NGT Transceiver System Technical Service Manual
08-05261 (sheet 2)
The transceiver must be in Service mode to make this adjustment (see
page 154, Accessing Service
Wait for at least five minutes after switching on the transceiver before
adjusting the frequency.
Select test channel 30.
Remove the coaxial connector from J2 on the RF/IF PCB in the RF unit.
This disconnects the exciter output to the PA.
Connect a frequency counter to the exciter output J2 – Tx.
Hold down 3 to switch on the tune carrier.
Adjust trimmer C451 (drawing 08-05235) to a frequency of 29.9 MHz ±3 Hz.
08-05889 (sheet 2)
If the PCB issue status is -06 or earlier, see drawing
The transceiver must be in Service mode to perform this check (see
page 154, Accessing Service
Wait for at least five minutes after switching the transceiver on before
adjusting the frequency.
Select test channel 30.
Remove the coaxial connector from J2 on the RF/IF PCB in the RF unit.
This disconnects the exciter output to the PA.
Connect a frequency counter to the exciter output J2 – Tx.
Hold down 3 to switch on the tune carrier.
Adjust trimmer C7 (drawing 08-05963) to a frequency of 29.9 MHz ±3 Hz.
NGT—Checks and adjustments
mode).
mode).
08-05889 (sheet 2).
173