Icom IC-4088A Guide

3
‘‘ENTERING THE ADJUSTMENT MODE
¡¡ Turn the transceiver’s power OFF.
™™ While connecting the “TEST”on the MAIN board to “GND”, and then turn power ON.
‘‘OPERATION ON THE ADJUSTMENT MODE
•Change the adjustment item : HM-75A’s [B] key
•Change the adjustment value : HM-75A’s [UP]/[DN] keys
•Verify the adjustment value : HM-75A’s [A] key
•Change the adjustment channel : IC-4088A’s [UP]/[DN] keys
•Change the adjustment group : IC-4088A’s [MODE]+ [UP]/[DN] keys
‘‘ADJUSTMENT ITEMS
When entering adjustment mode, displayed adjustment items indicator on the LCD as follow.
•Reference frequecy adjustment : Displayed
•Output power adjustment : Displayed
•FM deviation adjustment : Displayed
•CTCSS adjustment : Displayed
•Squelch adjustment : Displayed
EQUIPMENT
DC power supply
RF power meter
(terminated type)
Frequency counter
IC-4088A ADJUSTMENT PROCEDURES
1 PREPARATION
•When adjusting IC-4088A, HM-75A OPTIONAL SPEAKER-MICROPHONE is required.
• All adjustment items must be preformed at “ADJUSTMENT MODE”as show below.
‘‘REQUIRED TEST EQUIPMENT
GRADE AND RANGE
Output voltage : 6 V DC
Current capacity : 1 A or more
Measuring range : 1 mW–1 W
Frequency range : 300–600 MHz
Impedance : 50 Ω
SWR : Less than 1.2 : 1
Frequency range : 0.1–600 MHz
Frequency accuracy : ±1 ppm or better
Sensitivity : 100 mV or better
EQUIPMENT
FM deviation meter
Standard signal
generator (SSG)
GRADE AND RANGE
Frequency range : 30–600 MHz
Measuring range : 0 to ±10 kH
Frequency range : 0.1–600 MHz
Output level : 0.1 µV–32 mV
(–127 to –17 dBm)
CHANNEL NO.
1 ch.
2 ch.
3 ch.
4 ch.
5 ch.
6 ch.
7 ch.
8 ch.
9 ch.
10 ch.
11 ch.
12 ch.
13 ch.
14 ch.
FREQUENCY
462.5625 MHz
462.5875 MHz
462.6125 MHz
462.6375 MHz
462.6625 MHz
462.6875 MHz
462.7125 MHz
467.5625 MHz
467.5875 MHz
467.6125 MHz
467.6375 MHz
467.6625 MHz
467.6875 MHz
467.7125 MHz
•DISPLAYED CHANNEL’S FREQUENCY LIST

REFERENCE
FREQUENCY
[Fr]
OUTPUT
POWER
[PS]
[Ph]
FM DEVIATION
[dh]
[dL]
CTCSS
MODULATION
[to]
SQUELCH
SENSITIVITY
[Sq]
467.7125 MHz
450 mW
450 mW
± 2.10 kHz
± 2.10 kHz
± 0.30 kHz
Audio signal
disappears
•Operating channel : Ch 14
•Transmitting
•Operating channel : Ch 4
•Transmitting
•Operating channel : Ch 11
•Transmitting
•Operating channel : Ch 11
•Connect an audio generator to the [MIC]
jack and set as :
1 kHz/100 mV
rms
•Set an FM deviation meter as:
HPF : OFF
LPF : 20 kHz or 15
kHz
De-emphasis : OFF
Detector : (P–P)/2
•Set group No. : OFF (––)
•Transmitting
•Operating channel : Ch 4
•Transmitting
•Operating channel : Ch 11
•Set group No. : 24
•Transmitting
•Operating channel : Ch 1
•Connect an SSG to J1 on the RF unit and
set as:
Level : 0.13 µV*
(–125 dBm)
Modulation : OFF
•Receiving
•Set an SSG as:
Level : OFF
•Receiving
[UP]/[DN]
[UP]/[DN]
[UP]/[DN]
[UP]/[DN]
[UP]/[DN]
[UP]/[DN]
Verify
Loosely couple a fre-
quency counter to the
antenna.
Connect an RF power
meter to the RF test
port J1.
Connect an FM devia-
tion meter to the RF
test port J1.
Connect an FM devia-
tion meter to the RF
test port J1.
2 ADJUSTMENT MODE ADJUSTMENTS
The following adjustment must be performed at “ADJUSTMENT MODE”.
ADJUSTMENT ADJUSTMENT CONDITION MEASUREMENT VALUE HM-75A’s KEY
1
1
2
1
2
1
1
2
4
•Squelch sensitivity is adjusted
automatically when HM-75A’s
[A] button is pushed.