User's Manual

TM 1184 Issue 1 AL1 (May 1997) Page A1 - 21
d) On FL1 and FL2 turn the four adjusters ½ turn at a time until the power meter
indicates or the power supply current increases.
e) If no power appears slightly adjust VC2 or VC3 and repeat (d).
f) Tune the four adjusters of FL1 and FL2 for maximum power.
g) Tune VC1, VC2 and VC3 for maximum power and then RV1 to give a power meter
reading of 2.5W.
h) Re-adjust VC1, VC2 and VC3 for maximum power then RV1 for 2.5W ±0.2W.
Setting Data Deviation and Centre Frequency
48. To set the Data Deviation and Centre Frequency carry out the following procedure:
a) Select (M)arking (continuous ‘1's) from the Transmitter Test Menu. Measure the
output frequency to the nearest 10Hz.
b) Select (S)pacing (continuous ‘0's) from the Transmitter Test Menu and again
measure the output frequency to the nearest 10Hz.
c) Adjust RV2 as necessary until the measurement at (b) differs from the
measurement at (a) by the amount given in the TOTAL DEVIATION column of
Table 5 (within the specified tolerance).
d) Using a plastic trimming tool adjust VC5 until the mean of the two frequencies
measured at (a) and (b) is within 100Hz of the specified centre frequency of the
Transmitter.
Table 5: Data Deviation
CHANNEL DEVIATION TOTAL TOLERANCE
SPACING kHz DEVIATION
kHz kHz
25 ± 4.5 9 ± 200Hz
20 ± 3.6 7.2 ± 200Hz
12.5 ± 2.25 4.5 ± 100Hz
10 ± 1.8 3.6 ± 100Hz
e) Repeat sub-paragraphs (a) to (d) as necessary.
f) Select (A)nalogue from the Transmitter Test Menu. Adjust RV3 to give the specified
centre frequency of the Transmitter (to a tolerance of ±100Hz).