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TM-742 A/742 E/942 A
ADJUSTMENT
• 430/440 MHz Band (TM-742A/E, TM-942A, UT-440S)
Common Section adjustment
I
I
Item
Condition
Measurement point
Adjustment point
Specification
Test
equipment
Unit Terminal
Unit
Parts
Method
1. Lock
voltage
check
1. Frequency: 468.000 MHz
Receive
Digital
voltmeter
TX-RX TP2
Check the lock
voltage.
7.5 ~ 9.1 V (K, P)
7.0 -9.5 V (E, M)
Receiver Section Adjustment
Measurement point
Adjustment point
Item
Condition
Test
equipment
Unit Terminal
Unit
Parts
Method
Specification
1. Helical
scanning
adjustment
1. Frequency: 445.050 MHz
(K and P)
435.050 MHz
(E, M)
Spectrum analyzer: Center
of above frequency
Tracking generator:
Output: -30 dBm
Digital
voltmeter
Spectrum
analyzer
Tracking
generator
TX-RX
TCI,
TC2,
L3,
L4X3
438 44B
450
MHz (K, P)
430 435
440
MHz (E. M. M2)
Adjust each frequency as shown In the
figure.
2. Receive
sensitivity
check
1. Frequency: 445.050 MHz
(K and P)
435.050 MHz
(E. M)
SSG output: -9 dBji
Modulation: 1 KHz
Deviation: 3 KHz
Distortion
meter
Millivoltmeter
Oscilloscope
SSG
Rear
panel
EXT.SP
Check
IZdB'SINAD or more
3. Distortion
factor
adjustment
1. Frequency: 445.050 MHz
(K and P)
435.050 MHz
(E, M)
SSG output: 40 dBp.
Modulation: 1 KHz
Deviation: 3 KHz
AF output: 4 V/8 ohms
Distorltion
meter
Oscilloscope
SSG
Rear
panel
EXT.SP
TX-RX
L7
Minimize the
distortion factor.
5% or less
4. Signal
strength
meter
adjustment
(check)
1. Frequency: 445.050 MHz
(K and P)
435.050 MHz
(E, M)
SSG output: 23 dBji
Modulation: 1 KHz
Deviation: 3 KHz
SSG
TX-RX
VR1
Adjust so that all LEDs
go on. then one LED
goes off.
2. SSG output: 24 dB^i
Adjust the SSG
output so that all
signal strength
meter LEDs go on.
The SSG output is 20 ±
6 dBji.
5. Squelch
check
1. Frequency: 445.050 MHz
(K and P)
435.050 MHz
(E, M)
SSG output: Off
Modulation: 1 KHz
Deviation: 3 KHz
SSG
Rear
panel
EXT.SP
Set the SQL
control to the
closing position
Control position
8:00-11:00
BUSY should go out
2. SSG output: -14 dBji
Squelch should open,
and BUSY should
light up
SQL control fully
clockwise
Noise should
disappear
3. SGG output; —3 dB^
Squelch should
open
125
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