4 - 1
• 15–29.995 MHz
The RX signal from the antenna connector (CHASSIS; J1)
is applied to the RF AMP (Q505) through the band SWs
(D63, D64 and D73), LPF and the HPF.
The amplified signal is passed through the band SWs (D71
and D72), and then applied to another RF AMP (IC18).
• 30–117.995 MHz and 175–329.995 MHz
The RX signal from the antenna connector (CHASSIS; J1) is
applied to the RF AMP (Q36) through the band SW (D13) and
the BPF. The amplified signal is passed through the band SWs
(D34 and D71), and then applied to another RF AMP (IC18).
• 118–174.995 MHz
The RX signal from the antenna connector (CHASSIS; J1)
is applied to the RF AMP (Q14) through the band SWs (D74
and D75) and BPF. The amplified signal is passed through
the tuned BPF (D1 and D2) and band SWs (D25 and D71)
and then applied to another RF AMP (IC18).
• 330–469.995 MHz
The RX signal from the antenna connector (CHASSIS; J1)
is applied to the RF AMP (Q35) through the band SWs
(D3 and D75) and the BPF. The amplified signal is passed
through the tuned BPF (D4 and D5) and band SWs (D29
and D71), and then applied to another RF AMP (IC18 ).
• 470–832.995 MHz
The RX signal from the antenna connector (CHASSIS; J1)
is applied to the RF AMP (Q24) through the band SWs (D11
and D75) and BPF. The amplified signal is passed through
the band SWs (D32 and D71), and then applied to another
RF AMP (IC18).
• 833–1309.995 MHz
The RX signal from the antenna connector (CHASSIS; J1)
is applied to the RF AMP (Q26) through the band SW (D13)
and BPF. The amplified signal is passed through the band
SW (D36), and then applied to another RF AMP (IC18).
The signal from the RF AMP (IC18) is applied to the 1st IF
circuits.
4-1 RECEIVER CIRCUITS (RF UNIT)
EARPHONE ANTENNA
When using the connected earphone as an antenna, RX
signal from the earphone is applied to the RF circuits (except
0.10–1.895 MHz band), through the earphone antenna SW
(D101 and D109).
ATTENUATOR CIRCUIT
When the attenuator is activated, the PIN diode (D68)
is forward-biased and a 10 dB (approx.) attenuator is
composed.
The switching of D68 is carried out by Q521 with the control
signal “ATT.”
RF CIRCUITS
The RX signal from the antenna is applied to appropriate
RF circuits, according to the RX frequency.
• 0.10–1.895 MHz
When using an external antenna;
The RX signal from the antenna connector (CHASSIS; J1)
is applied to the RF AMP (Q505) through the band SWs
(D66, D67 and D73) and LPFs.
When using the internal bar antenna;
The RX signal from the internal bar antenna (CHASSIS;
EP2) is applied to the RF AMP (Q505) through the ANT SW
(D76).
The amplified signal is passed through the band SWs (D71
and D72), and then applied to another RF AMP (IC18).
• 1.9–14.995 MHz
The RX signal from the antenna connector (CHASSIS; J1)
is applied to the RF AMP (Q505) through the band SWs
(D65, D70 and D73), LPF and the BPF.
The amplified signal is passed through the band SWs (D71
and D72), and then applied to another RF AMP (IC18).
• RF CIRCUITS
SECTION 4. CIRCUIT
DESCRIPTION
RF
AMP
BPF
BPF
BPF
TUNED
BPF
TUNED
BPF
J1(CHASSIS)
BPF
BPF
ATT
ANT
SW
LPF
LPF
BPF
HPF
RF
AM P
RF
AM P
RF
AM P
RF
AM P
RF
AM P
RF
AM P
BAND
SW
BAND
SW
BAND
SW
BAR
ANTENNA
BAND
SW
BAND
SW
BAND
SW
ATT
RF UNIT
D13,D31,
D73,D75
D63,D65,D66
Q510,D76
D64,D67,D70
Q505,Q527
D3,D11,D74
Q14
D1,D2
Q35
D4,D5
Q24
D25,D29,D32,
D34,D72
Q36
Q26
D36,D71
IC18
To the 1st IF circuits
0.10-29.995 MHz
0.10-1.895 MHz
0.10-
1.895 MHz
1.9-14.995 MHz
15-29.995 MHz
118-174.995 MHz
330-469.995 MHz
470-832.995 MHz
30-117.995 MHz
175-329.995 MHz
833-1309.995 MHz
Q521
D68
EARPHONE
ANT SW
Q514,
D101,D109
ANT CONNECTOR
EARPHONES ANTENNA
J2
EXT SP
