FRIENDCOM FC-301/D User manual

FC-301D
SERVICE MANUAL
SHENZHEN FRIENDCOM TECHNOLOGY DEVELOPMENT CO.,LTD
ADD: 2/F MULTIFUNCTION BUILDING DONGPENG INDUSTRIAL PARK WUHAO
ROAD NORTH SECTION OF HI-TECH PARK SHENZHEN 518057 CHINA
TEL: [phone] FAX: [phone]

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TABLE OF CONTENTS
TABLE OF CONTENTS .......................................
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01
．．
SPECIFICATIONS ...........................................02
FC-301D CIRCUIT DIAGRAM.................................07
INTRODUCTION............................................08
FEATURES.................................................08
THEORY OF OPERATION....................................09
MAINTENANCE AND REPAIR................................18
PROGAMMING.............................................21
ALIGNMENT PROCEDURE...................................37
ALIGNMENT POINTS DIAGRAM..............................43
COMPONENT REPLACEMENT................................44
TROUBLESHOOTING GUIDE.................................48
WIRING DIAGRAM..........................................49
FC-301D DIGITAL BOARD PARTS LIST ........................50
DIGITAL BOARD SCHEMATIC ................................54
DIGITAL PCB ASSEMBLY ....................................58
FACTORY SETTING DIAGRAM ...............................60
EXPLODED VIEW & PARTS LIST .............................61

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SPECIFICATION
GENERAL
Equipment Type…………………………………Data Radio
Performance Specification…………..................TIA/EIA-603 & ETS 300-113
Band …………………………………………...UHF/VHF
Channel Spacings………………………………25KHz,12.5KHz programmable
RF Output Power……………………………….1W / 5W Programmable
Modulation type ………………………………..16K0F3E,8K5F3E
Intermediate Frequency………………………… 45.1MHz & 455KHz
Number of Channels…………………………….16
Frequency Source ……………………………….Synthesizer
Operation Rating…………………………………Intermittent
5:5:90 ( TX: RX: Standby )
Power Supply ……………………………………12.5V DC Nominal Voltage
Temperature Range
Storage………………………………………from –40°C to +80°C
Operating……………………………………from –30°C to +60°C
Current Consumption
Standby (Muted) ……………………………≤40mA
Transmit 5 Watts RF Power …………………< 1.5A
Transmit 1 Watt RF Power…………………..<0.8A

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Frequency Bands :………………………………RX UHF: U1 400 – 470 MHz
…………………..…………….TX UHF: U1 400 – 470 MHz
Dimensions………………………………………..(120mm)L x (60mm)W x (20mm)H
Weight……………………………………………..≤150 grams
TRANSMITTER
Sustained Transmission…………………………… Nominal conditions
Time: 5 10 30sec
Power: >95% >95% >90%
Frequency Error…………………………………..±2.5 ppm
Frequency Deviation:
25kHz Channel Spacing……………………..≤±5.0kHz,
12.5kHz Channel Spacing……………………≤±2.5kHz,
Audio Frequency Response………………………. Within +1/-3dB of 6dB octave
@300Hz to 2.55kHz for 12.5kHz C.S
@300Hz to 3.0khz for 25kHz C.S
Adjacent Channel Power
25kHz…………………………………………< 70 dBc @ Nominal Condition
<65 dBc @ Extreme Condition
12.5kHz ………………………………………< 60 dBc @ Nominal Condition
< 55 dBc @ Extreme Condition
Conducted Spurious Emission …………………….< -36 dBM
Modulation Sensitivity……………………………. 100mV RMS@60% peak Dev.
Hum & Noise:
25kHz Channel Spacing………………….….>40 dB (with no PSOPH)

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12.5kHz Channel Spacing………………..……>36 dB (with POSPH)
Modulation Symmetry ……………………………..<10% Peak Dev@1kHz input
for nominal dev +20dB
Load Stability……………………………………No osc at >= 10:1 VSWR all
phase angles and suitable antenna
Nodestroyat>=20:1allphaseangle
RECEIVER
Sensitivity(12dB Sinad) …………………………..UHF <-117 dBm,
VHF<-1[email protected]
Amplitude Characteristic………………………….<±3dB
Adjacent Channel Selectivity:
25 kHz Channel Spacing …………………….≥70dB @ Nom.,
12.5kHz Channel Spacing…………………….≥60dB@Nom.,
Spurious Response Rejection………………………70dB
Image Response…………………………………… > 70 dB
IF Response ………………………………………. >70 dB
Others………………………………………………> 70 dB
Intermodulation Response Rejection………………≥65 dB
Conducted Spurious Emission @ Nominal Conditions………<-57 dBm
AF Distortion ………………………………………………....<5% @ Nom.,
<10%@ Extreme Condition
RX Hum & Noise:
25.0kHz CP……………………………………………< 40dB No PSOPH

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12.5kHz CP ………………………………………..…< 40dB with PSOPH
Receiver Response Time …………………………….< 20ms
Squelch Opening sensitivity: ………………………-118dBm
Squelch Closing sensitivity ……………………….. -121dBm
Squelch Attack Time:
RF Level at Threshold ………………………… <40ms
RF Level at Threshold +20dB…………………<30ms
L.O. Frequency Temperature Stability…………….1 st <2.5 ppm,
2 nd <10 ppm for –30°C to +60°C
L.O. Frequency Aging Rate………………………….±2 ppm/year
REFERENCE CRYSTAL
Frequency…………………………………………………. 13MHz
Temperature Characteristic……………………………+/- 2.5PPM
from –30°C to +60°C
Aging Rate……………………………………………….< 2ppm/year in 1 st year
<1ppm/year thereafter
TX to RX ………………………………………………… < 20
RX to TX ………………………………..……………….. < 25
ENVIRONMENTAL ( performance without degradation unless stated)
Temperature……………………………………………… deg C
Operating………………………………………………….-30° to +60°C Degradation
Specified@Extreme
Storage …………………………………………………… -40°C to +80°C

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Recharging ……………………………………………… -10 to +55
ESD………………………………………………………. 20kV (C-MIC >= 15kV)
Vibration………………………………………………… MIL STD 810 C Procedures I,II,V
and IEC68 26
· Due to contintuning researching and development the company reserves the
right to alter these specifications without prior notice.

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FC-301D CIRCUIT DIAGRAM

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INTORDUCTION
The FC-301D Series of RF Link Modules from Friendcom utilizes the latest
technology in its design and manufacturing. Both the UHF and VHF models
are PLL (Phase Lock Loop Synthesizer) / microprocessor controlled, and offer
one to five watts of power with 16 channel capability. Multiple functions
including 1200 to 9600 baud rates,AC audio coupling,GMSK and FSK
modulation are standard in these fully programmable wide bandwidth RF Link
Module units.
FEATURES
●16 Channels
●1 / 5 Watt Programmable Output
●12.5 / 25 kHz Programmable Channel Spacing

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THEORYOFOPERATION
The Base Band signal circuits
It contains the CPU, power circuit ,TX signal circuit,RX signal circuit.
The CPU circuit and power circuit
From Block Digram above: The DC power was regulated to 8 volt by
IC500 ,and supplied to the RF part. IC504 convert 8 volt to 5volt and supply to
IC510. Q500 is RX power supply switch, Q502 is TX power supply switch.
IC501 supply 3.6V to PLL IC. Channels can be selected by the switch (CF3).
IC510 controls digital frequency synthesize by PLL STR ,PLL DATA and PLL
CCK.

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The CPU SQ pin detect the signal from PIN14 of IC2. when there is no
receiveing signal, the input level is about 1.2V, and PIN8 of IC510 output high
level(5V). When detect input receiving signal, the input level is about 0V, and
PIN8 of IC510 output low level(5V).
TX signal circuit
From the above Block Diagram : IC801 is audio/Data and UART signal switch.
When the SW pin is high ,audio/data signal can go through IC801. S1 is a
switch between audio and data input, when transmit audio, MIC IN port is
shorted, when transmit data, DATA IN port is shorted. As it was data signal it
will pass through DATA-IN port and amplified by U1A, then it was coupling
by C431 and pass to U1B for amplify again;as it was audio signal it will pass

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through MIC-IN port and amplified by U1B; then it will divide into two signal,
one will coupling by C405 R407 and fed to TCXO for TX modulation; the
other one was amplified by U1C,after coupling by C428,R404,C427 ;the voice
signal is filtered by U1D which is a low pass filter, the output of U1D is then
fed to VCO for TX modulation after coupling by C415,R403 again. Q401 is
a Wideband /narrow-band switch .
RX signal circuit
From the above Block Diagram; The resulting AF signal from IC2 enters base
band processing chip U2. First coupling by C412 and amplified by U2A ,then
it is filtered by U2B which is a low pass filter.After U2B,one signal pass
through IC801 and send to COM pin 2, one signal is amplify by audio
amplifierIC8, and sent to the horn directly. Q403 is a audio PA switch.

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RF circuit
Main include PLL circuit / TX circuit /RX circuit
PLL Frequency Synthesizer
From the above Block Diagram : PLL circuit generates the first local oscillator
signal for reception and RF signal for transmission.
1. PLL Circuit
Step frequency of PLL can be 5.0 KHz or 6.25 KHz. A 13MHz reference
oscillator signal is divided at IC301 by a counter to generate a 5.0 KHz or 6.25
KHz reference frequency. Output signal from VCO is buffer amplified by
Q301 and divided at IC301 by a frequency divider. The divided signal is
compared with 5.0 KHz or 6.25 KHz reference signal in the phase
comparator of IC301. The output signal from phase comparator is filtered
through a low pass filter(Q320/Q321/ R39/C328/R318/R31/C327/R316/C326)

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to generate a level D.C., and the level D.C. controls oscillator frequency by
controlling VCO.
2. VCO
The operating frequency is generated by Q302 in transmit mode and by Q307
in receive mode. Operating frequency generate a control voltage by phase
comparator to control varactor diodes so that the oscillator frequency is
consistent with the MCU preset frequency(D301、D302、D303 and D304 in
transmit mode, and D307、D308、D309 and D310 in receive mode). T/R pin is
set high level in receive mode, and low level in transmit mode. The output
from Q302 and Q307 is amplified by Q304 and sent to buffer amplifier.
3. Unlock Detector
An unlock condition appears if low level appears at MUXOUT pin of IC301.
Transmission is forbidden if this condition is detected by CPU IC510.

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Receiver
The receiver utilizes double conversion superheterodyne (UHF)/(VHF).
1. Front-end RFAmplifier
The signal from antenna is amplified at LNA (Q15) after passing through a
transmit/receive circuit and a band pass filter
（D211/D212/D241/C264/C260/L25/L26）. Before passing the first mixer
（T3、T4、TC3）, the amplified signal is filtered through another band pass
filter（D208/D209/C240/C257/C258/L23/L24）to remove unwanted signals.

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2. First Mixer
The signal from RF amplifier is mixed with the first local from PLL
frequency synthesizer circuit at the fix mixer (T3、T4、TC3) to create a
45.1MHz first IF signal. The first IF signal is then amplified by Q13 and fed
through a crystal filter (XF1) to further remove unwanted signals.
3. IFAmplifier
The first IF signal is amplified by Q13 before passing through crystal filter and
by Q12 after crystal filter and then enters IF processing chip IC2. The signal
from IC2 is mixed with the second oscillator signal again in IC2 to create a 455
KHz second IF signal. The second IF signal then passes through a 455KHz
ceramic filter (wideband: CF2，narrowband: CF1) to eliminate unwanted
signals before it is amplified and detected in IC2.
4. Narrowband/Wideband Switch Circuit
Pin W/NCON of IC510 outputs narrowband (high level) and wideband (low
level) controlling signal respectively to turn on corresponding diode-connector,
and to choose ceramic filter CF2 (wideband) or CF1 (narrowband) to filter
useless spurious signal.

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Transmitter
1. RF PowerAmplifier
The transmit signal from VCO buffer amplifier (Q304、Q111) is amplified by
Q1 and Q2. The amplified signal is then amplified by the power amplifier I102
to create 5.0W RF power.
2. Antenna Switch and LPF
Output signal from RF amplifier passes through a low-pass filter network and
a transmit/receive switch circuit comprised of D102，D106 and D107 before it
reaches the antenna terminal. D106 and D107 is turned on (conductive) in
transmit mode and off (isolated) in receive mode.

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3. APC
The automatic power control (APC) circuit stabilizes the transmit output
power by detecting the forward and backward power of final stage amplifier.
IC1 (2/2) compares the preset reference voltage with the voltage obtained from
the regulated power signal. APC voltage is proportional to the forward and
backward power. The output voltage controls the bias voltage of power
amplifier module.The output power can be controlled by the software.

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MAINTENANCEANDREPAIR
GERNERAL
When removing or fitting, use the Exploded View and Parts List, located on
page 61 in conjunction with the following procedures:
·WARNING: Disconnect the FC-301D from all external equipment at the
connector prior to disassembly.
REMOVING & REPLACING THE UPPER COVER
Removing the Upper Cover:
1. Unscrew the four side cover
mounting screws located on the side
cover of the radio.
To replace the Upper Cover:
1. Reverse the steps taken to remove the
Upper Cover.
Figure1-Uppercoverremoval

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REMOVING&REPLACING THE INTERPHASE CONNECTION BOARD
Removing the interphase connection board:
1.Remove the Upper Cover (refer to Removing & Replacing the Upper
Cover).
2.Disconnect the DB9 pin connector on CON401.
3.Unscrew the two mounting screws on the Amplifier module.
4.Remove the interphase connection board directly.
To replace interphase connection board:
1. Reverse the steps taken to remove the interphase connection board
Figure 2 Interphase connection board removal