B6
Z4
B30
Z30
B32
Z32
B26
Z26
B14
B10
JU22
JU23
B22
JU18
B24
B18
Z12
B12
D4
B28
Z14
D30
D28
D32
SW1
D20
D22
D24
D26
TP4
JU11
JU10
JU12
JU14
JU13
JU15
+9.5V
JU17
JU16
JU20
JU24
B20
B4
ENHANCED RF AMPLIFIER FRONT END
HELICAL
FILTER
RF FILTER
+9.5 VDC
POWER SUPPLY
U1, U12, U13
+6.0 VDC
+4.75 VDC
-6.0 VDC
+9.5 VDC
4 POLE XTAL
FILTER
4 POLE XTAL
FILTER
PLL
CONTROL
MICROPROCESSOR
VCO
HIGH STABILITY
9.6/10 MHz REFERENCE
(± 1ppm -40°C to +60°C)
FRONT PANEL RF INPUT
(TYPE N CONNECTOR)
LOW POWER FM IF
21.855 MHz
2nd LO
LIMITER
455 KHz
CERAMIC
FILTER
DEMODULATOR
TP6
JU3
CHANNEL NUMBER
MOST SIG
LEAST SIG
+9.5 VDC
RECEIVED SIGNAL STRENGTH
INDICATOR (RSSI) BUFFER
FLAT AUDIO
FILTER / BUFFER
Fc = 7 KHz
DISCRIMINATOR
OUTPUT
(BUFFERED)
JU5
7 POLE VOICE BAND FILTER
(U5, U6)
300 Hz - 3 KHz
SUBTONE LOWPASS FILTER
Fc = 250 Hz
JU7
+9.5 VDC
JU6
JU21
600
Ω
BALANCED
OUTPUT
DE-EMP AUDIO
OUTPUT
CTCSS OUTPUT
(FILTERED)
SIGNAL STRENGTH
(RSSI)
+6.0 VDC OUTPUT
+9.5 VDC SUPPLY
AUX SPEAKER
OUTPUT
FLAT AUDIO
OUTPUT
JU27
DE-EMPHASIS AUDIO
LEVEL ADJUST (R58)
DE-EMPHASIS AUDIO
DE-EMPHASIS AUDIO
AUDIO SQUELCH GATE
FLAT AUDIO
FLAT AUDIO
HIGH LEVEL DRIVE
ADJUST (R64)
FLAT AUDIO LEVEL
ADJUST (R66)
JU19
+6.0 VDC
+9.5 VDC
COR PULLUP
(10K
Ω)
JU26
COR (NORMAL)
COR
(OPTO-ISOLATED)
COR
(POWER MOSFET)
OPTIONAL
RELAY
NO 1
NC 1
COM 1
COM 2
NC 2
NO 2
MUTE
SQUELCH
OVERRIDE
GROUND
DE-EMPHASIS NETWORK
6 dB PER OCTAVE
HIGH PASS
NOISE FILTER
Fc = 10 KHz
CHANNEL SEL 3
CHANNEL SEL 2
CHANNEL SEL 1
CHANNEL SEL 0
SYNTH BOOTSTRAP
SYNTH DATA OUT
SYNTH DATA IN
°T
FINE FREQUENCY ADJUST
(ACCESS HOLE THROUGH
SYNTHESIZER COVER)
TRUE RMS NOISE
POWER DETECTOR
SQUELCH TRIGGER
COMPARATOR
TEMPERATURE COMPENSATED
SQUELCH NOISE AMPLIFIER
SQUELCH
THRESHOLD
ADJUST (R88)
SQUELCH
HYSTEREIS
ADJUST (R115)
JU34
Q1
U2
RECEIVER MAIN POWER
(FRONT PANEL)
U3
U18
U4
U8
U8
U9
U17
OPTO ISOLATOR
U7
U19
U13
U14
U16
TP7
TP8
TP10
INTERNAL COR
TP11
TP12
TP1 TP3 TP2
Q5
RECOVERED AUDIO
AMPLIFIER BIAS
ADJUST (R13)
EXTERNAL REFERENCE INPUT
(OPTIONAL, FRONT PANEL SMA)
Q7
JU29
U18B
DISCRIMINATOR DC
COUPLED BUFFER
JU25
21.4 MHz
IF AMP
COAX
COAX
RECEIVER SQUELCH
DISABLE
(FRONT PANEL)
AUDIO ROUTING JUMPERS
+9.5 VDC SUPPLY
Z6
Z18
D10
D6
D2
D8
D12
JU4
OS-3H SYNTHESIZER MODULE
Z24
PRIORITY
COR
LO FILTER
RF AMP
10 dB
MIXER
IF BUFFER
BOARD
JU2
FREQUENCY
REFERENCE
9.6/10 MHz
SELECT
5 VDC SUPPLY
&
8VDC SUPPLY
JU1
B
A
INTERNAL / EXTERNAL
REFERENCE SELECT
JU37
JU43
JU44
+
+
+
-120
-100.0
-80.0
-60.0
-40.0
RF SIGNAL LEVEL (dBm)
4.70
3.70
2.70
1.70
0.70
RSSI
OUT
PUT
VOL
TA
GE (Vd
c)
TP9
0 1
2
3
4
5
6
7
8
9
0 1
2
3
4
5
6
7
8
9
0 1
2
3
4
5
6
7
8
9
0 1
2
3
4
5
6
7
8
9
RLY1
JU8, JU9
+9.5 VDC
2.9 VR-3H040 Family Enhanced Receiver Block Diagram
2-10
VHF Enhanced Extra Wideband Receiver Instruction Manual IM10-VR3H040-AB
B0233