Specifications
CONSTRUCTION
band from channel 2 to channel 12) to
operate the domestic receiver directly.
The block diagram of a satellite re-
ceiver is shown in Fig. 3(a).
The coaxial cable from LNB is con-
nected to the tuner (which contains RF
and IF modules) through ‘F’ socket. To
simplify the design for an average con-
structor, the Mitsumi TSU2-EOIP tuner
is used in the circuit. Pinout of the tuner
are shown in Fig. 3(b) while its specifica-
tions are given in Table II. It is a
readymade tuner with tunable range from
950 MHz to 1450 MHz, giving baseband
output directly with audio sub-carrier.
The tuner module is tuned with a volt-
age (V
T
) between 0 and 20V and requires
no high/low band switch. It has a termi-
nal for applying the supply voltage for
LNB, which is carried to the LNB via the
down lead, coaxial cable type RG-8 or
RG-11. The module itself is fed +12V and
+5V DC for its operation. The complete
circuit diagram of the receiver is shown
in Fig. 4.
The baseband output from the tuner
module is fed to the audio stage, video
stage, and signal-strength indication cir-
cuit.
Audio section. It consists of three
stages: sound intermediate frequency
(SIF) stage, sound driver stage, and sound
output stage.
The audio signal from the baseband
output of tuner module is separated with
the help of an LC (inductance-capacitance)
tuned wave-trap circuit comprising capaci-
tors C1 through C4 and inductors L1
through L3. SIF signal is fed to pin 6
(limiter section) of IC1 (NE564). The posi-
tive DC voltage is fed to pins 1, 3, 9, and
10 of IC1.
Audio IF fre-
quency can be
varied by varying
the voltage of
VCO (voltage-con-
trolled oscillator)
of the IC. The
VCO voltage is
controlled with
the help of
potmeter VR2,
which is con-
nected to pin 13 of
IC1 and acts as
an audio IF fre-
quency-controller.
Varactor diode D1
(MV2109) is con-
nected across pins 12 and 13 through ca-
pacitors C9 and C11.
Audio bandwidth can also be adjusted
PARTS LIST
Semiconductors:
IC1 - NE564 phase locked loop
IC2 - NE592 video amplifier
IC3 - NE555 timer
IC4, IC7 - 7805, 5V regulator
IC5 - 7818, 18V regulator
IC6 - 7812, 12V regulator
T1 - T6 - 2SC2458 npn transistor
D1 - MV2109 varicap diode
D2, D5, D6 - 1N4148 switching diode
D3, D4 - OA79 detector diode
D7 - D14 - 1N4007, 1-amp silicon diode
LED - Red LED
Resistors (all 1/4W, ± 5% carbon, unless
stated otherwise)
R1, R3, R11 - 220 ohm
R2, R16, R20
R27 - 1 kilo-ohm
R4, R19 - 1.8 kilo-ohm
R5 - 390 ohm
R6 - 1.2 kilo-ohm
R7, R8, R12
R17, R35 - 2.2 kilo-ohm
R9 - 120 ohm
R10 - 5.6 kilo-ohm
R13, R14, R15
R25,R26, R39 - 10 kilo-ohm
R18 - 180 ohm
R21, R33 - 100 ohm
R22, R24 - 150 ohm
R23 - 330 ohm
R28 - 470 ohm
R29 - 82 ohm
R30 - 47 kilo-ohm
R31 - 270 ohm
R32 - 1.5 kilo-ohm
R34 - 8.2 kilo-ohm
R36 - 120 kilo-ohm
R37, R44 - 82 ohm
R38 - 100 kilo-ohm
R40, R41 - 560 ohm
R42 - 15 ohm
R43 - 68 ohm
VR1, VR2,
VR7, VR8 - 4.7 kilo-ohm linear
potentiometer
VR3, VR4,
VR5, VR6 - 4.7 kilo-ohm presets
Fig. 5: Power supply unit
Capacitors:
C1, C7, C11, C18
C21, C27 - 1kpF ceramic disc
C28, C29, C44
C2, C3, C4,26- 56pF ceramic disc
C5, C6, C9, C13
C15, C31 - 0.01µF ceramic
C8 - 1µF, 25V electrolytic
C10 - 27pF ceramic disk
C12 - 18pF ceramic disk
C14, C16,C24- 22µF, 25V electrolytic
C17 - 68pF ceramic disk
C19, C20 - 150pF ceramic disk
C22 - 10pF ceramic disk
C23 - 0.1µF ceramic disk
C25 - 220µ/25V electrolytic
C30 - 0.22µF ceramic disk
C32 - 100µF, 25V electrolytic
C33 - 68µF, 25V electrolytic
C34 - 2200µF, 50V electrolytic
C35 - 3300µF, 50V electrolytic
C43 - 10 kpF ceramic disk
C37-C40, C45
C46, C36 - 0.1µF, 400V, ceramic disk
C41 - 33 µF, 40V electrolytic
C42 - 100 µF, 25V electrolytic
Miscellaneous:
- VU meter (250µA)
- Mitsumi tuner (TSU2-
EOIP)
- PCB
- Chassis, knobs, on/off
switch
- Heat-sink for regulators
L1, L2, L3 - 4.7µH inductor (fixed)
L4 - 2.2µH inductor (fixed)
- 3-pin screw type connector
for motorised feed horn pulse
X1 - 230V AC primary to
17V AC, 1-amp and
24V AC, 1-amp secondary
transformer
S1 - DPDT rocker switch
S2 - On/off switch
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