Kenwood TH-28A Service Manual page 41

ADJUSTMENT
TH-28A/E
Measurement Adjustment
Item Condition ont ont Unit | Terminal! Unit | Parts Method Specifications/Remarks
5. TONE 1) F key : Push Power meter | RF ANT Check Display "T" on. ;
deviation # key : Push Linear , DEV : 0.5 to 1.25kHz
PTT : ON detector
K,P,MLM2,X f. counter
2) TONE key : Push AG MIC Check During TONE key pushing down,
E,E2,E3,E6,T Oscilloscope display "T" on, and transmit mode.
AF V.M DEV : 2.5 to 4.5kHz
6. CTCSS 1) F key : Push Check Display "CT" on.
(TSU-7) 3 key : Push
PTT : ON CTCSS|VR1 *£0.7kHz +0.5 to £1.25kHz J
VHF RX Adjustment
i Measurement Adjustment
item Condition | Tast- . . . | Specifications/Remarks
equipment Unit | Terminal | Unit | Parts Method
1. BPF 1) Tracking generator output Tracking | RF ANT RF L220 | Align the L220, L221,
' :-40dBm generator L221 | L223 and set the wave-
Connect the spectrum Spectrum TP L223 | form of spectrum
analyzer to TP1. analyzer analyzer to Fig. 1.
2. Receive 1) Frequency : 146.050MHz SSG RF ANT Check SINAD 12dB or more.
sensitivity.
coer eee PAMUM2,X |.
_. _ .
a
145.050MHz Oscilloscope SP
E,E2,£3,E£6,T | Distortion
SSG output : 0.18uv/-122dBm | meter
MOD : 1kHz AF V.M
DEV :£3kHz
AF VR : 0.63V/8Q
2) Frequency : 144.050MHz
3} Frequency : 147.950MHz
K,P,M.M2,X
145.950MHz
E,E2,E3,E6,T
4) Display : VFO mode Check S/N 10dB or more.
F key (1 sec} : Push
LOW key : Push
ak... frequency :118.000MHz.._. ~
K,P only
SSG output : 1.6uV/-103dBm
AM MOD : 1kHz/60%
5) MHz key : Push Check SINAD 12dB or more.
Frequency : 162MHz (Encoder)
SSG output': 1pV/-107dBm
MOD : tkHz
DEV : £3kHz
3. S-meter 1) Frequency : 146.050MHz SSG RF ANT IF VR3 The 1st segment is | When VR3 is unable to be adjusted
; K,P,M,M2,X just turned on. as follows, at the point of 9 o'clock
145.050MHz Oscilloscope of VR3 and SSG output is 0.28uV
E,E2,E3,E6,T | SP /~118dBm, the ist segment or more
SSG output : 0.18uV/-122dBm | Ammmeter is acceptable.
2) SSG output : 8.9uV/-88dBm_ | AF V.M Check All segments on.
3) SSG output : O.1pV/-127dBm Check All segments off.
4. Squelch 1) SSG RF : OFF Check SQL knob scale : 1.5 to 4
SQL VR : Noise disappear point 65mA or less.
2} SSG output : O.1pV/-127dBm Check Squeich should be open.
3) SQL VR : MAX Tight squelch Squelch should be close.
4) SSG output : 0.4pV/-116dBm Check Squelch should be open.
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