Sailor RT2047/D Service Manual
TECHNICAL MANUAL
FOR
COMPACT VHF RT2047/D
S.P. RADIO A/S
AALBORG
DENMARK
RT2047 DSC - PART I
CONTENTS
1 GENERAL INFORMATION 1-1
1.1 INTRODUCTION 1-1
2 INSTALLATION 2-1
2.1 INSTALLATION HINTS 2-1
2.2 MOUNTING POSSIBILITIES 2-2
2.3 DIMENSIONS AND DRILLING PLAN 2-4
2.4 HANDSET 2-9
2.5 MICROTELEPHONE CONNECTOR 2-9
2.6 POWER SUPPLY 2-9
2.7 POWER AND EXT. LOUDSPEAKER CONNECTOR 2-10
2.8 ANTENNAS 2-10
2.9 SPECIAL OPTIONS 2-10
2.10 REAR VIEW OF VHF RT2047 2-11
2.11 STANDARD FREQUENCY TABLE 2-12
RT2047 DSC - PART II
CONTENTS
1 GENERAL INFORMATION 1-1
1.1 GENERAL DESCRIPTION 1-1
1.2 TECHNICAL DATA 1-2
1.3 CONTROLS 1-3
1.4 PRINCIPLE OF OPERATION 1-5
1.5 BLOCKDIAGRAM 1-7
2 CIRCUIT DESCRIPTION 2-1
2.1 RECEIVER UNIT MODULE 100 2-1
2.2 RX-SYNTHESIZER UNIT MODULE 200 2-4
2.3 TX-EXCITER UNIT MODULE 300 2-8
2.4 TX-POWER AMPLIFIER MODULE 400 2-13
2.5 ANTENNA RELAY (500) 2-13
2.6 INTERFACE UNIT MODULE 6/600 2-17
2.7 KEYBOARD UNIT MODULE 7/700 2-24
2.8 DUPLEX FILTER MODULE 800 2-28
2.9 FILTER UNIT MODULE 9/900 2-29
2.10 MAIN DIAGRAM 2-32
2.11 MICROTELEPHONE INSTALLATION 2-34
2.12 SPECIAL INSTALLATION WITH 2 MICROTELEPHONES 2-35
2.13 SPECIAL INSTALLATION WITH 3 MICROTELEPHONES 2-36
2.14 MECHANICAL DIMENSIONS FOR HANDSET 2-37
2.15 DC POWER SUPPLY N418 2-39
2.16 N420 24V/12V REGULATOR 2-42
3 MECHANICAL DISASSEMBLING AND MODULE LOCATION 3-1
3.1 MECHANICAL DISASSEMBLING 3-1
3.2 MODULE LOCATION 3-3
4 SERVICE 4-1
4.1 MAINTENANCE 4-1
4.2 ADJUSTMENT INSTRUCTIONS 4-1
4.3 PROPOSAL FOR NECESSARY MEASURING INSTRUMENTS 4-1
4.4 CALIBRATION OF THE TEST PROBE 4-2
4.5 PROCEDURE FOR CALIBRATION 4-2
4.6 ADJUSTMENT PROCEDURE 4-3
4.7 TROUBLE-SHOOTING 4-6
4.8 REPLACEMENT OF COMPONENTS 4-6
4.9 REPLACEMENT OF MODULES 4-6
4.10 NECESSARY ADJUSTMENTS AFTER REPLACEMENT OF
A MODULE 4-7
4.11 PIN CONFIGURATION 4-9
4.12 PIN CONFIGURATIONS, BLOCK & SCHEMATIC
DIAGRAMS FOR IC’S 4-10
5 PARTS LIST 5-1
9546
RT2047 DSC - PART I
CONTENTS
1 GENERAL INFORMATION 1-1
1.1 INTRODUCTION 1-1
RT2047 DSC - PART I
1 GENERAL INFORMATION
1.1 INTRODUCTION
The RT2047 VHF Radiotelephone has been designed to be used with the Compact 2000 Module
Programme.
The VHF RT2047 can either be installed and operated as an independent unit or in combination with the
other modules in the Compact 2000 programme. These modules include a complete range of SSB
transmitters and receivers, MF/HF Digital Selective Calling unit and/or radiotelex equipment, a scrambler
that ensures complete communication secrecy and a VHF Digital Selective Call (DSC) unit. The DSCunit features direct dialling and reception of ship to shore, shore to ship and ship to ship calls as well as
automatic distress calls etc.
The VHF RT2047 has been constructed to withstand the most extreme conditions experienced in small,
semi-open boats. Its compact, weather proof construction ensures a degree of resistance to sea spray.
The printed circuits, which have made possible a combination of compactness and exceptional
performance, are coated with a special, moisture-repellent lacquer.
In the design of this VHF radiotelephone, S. P. Radio have taken into account all conditions it will be
exposed to in day-to-day operation. However, even a product of this high quality requires regular service
and maintenance, and we recommend the user to observe the maintainence instructions in the instruction
book.
S. P. Radio is Europe’s leading producer of maritime radio communication equipment - a position which
has been maintained by means of constant and extensive product development. We have a world-wide
network of dealers with general agencies in fifty countries. All our dealers are well-trained and will be able
to service all products.
PAGE 1-1
RT2047 DSC - PART I
CONTENTS
2 INSTALLATION 2-1
2.1 INSTALLATION HINTS 2-1
2.2 MOUNTING POSSIBILITIES 2-2
2.3 DIMENSIONS AND DRILLING PLAN 2-4
2.4 HANDSET 2-9
2.5 MICROTELEPHONE CONNECTOR 2-9
2.6 POWER SUPPLY 2-9
2.7 POWER AND EXT. LOUDSPEAKER CONNECTOR 2-10
2.8 ANTENNAS 2-10
2.9 SPECIAL OPTIONS 2-10
2.10 REAR VIEW OF VHF RT2047 2-11
2.11 STANDARD FREQUENCY TABLE 2-12
RT2047 DSC - PART I
2 INSTALLATION
2.1 INSTALLATION HINTS
Before installation of a VHF RT2047 the following points must be observed:
WHAT FACILITIES WILL HAVE TO BE ENABLED ?
Selcall, private channels, US-mode, dual watch, scanning facilities, etc. The procedure for enabling these
facilities is described in the manual: INSTRUCTIONS FOR IDENTITY AND SERVICE PROGRAMMING
OF VHF RT2047. This manual will only be delivered to dealers and general agents where it will be at the
disposal of trained personal in their service facilities.
IN WHAT WAY TO INSTALL THE VHF RT2047 ?
In section 2.2. MOUNTING POSSIBILITIES there’s installation instructions for the VHF RT2047 as an
independent unit or in combination with other units in the Compact 2000 programme.
HANDSET.
Installation of handset, see section 2.4. HANDSET.
EXTERNAL LOUDSPEAKER.
An external loudspeaker 4-8 ohm (4 W) can be connected to the power connector J802 pin 1 and 6, see
section 2.7. POWER CONNECTOR + EXT. LOUDSPEAKER.
SPECIAL OPTIONS:
The signals ‘remote alarm for selcall’, ‘AF to information decoder’, ‘AUX I’ , ‘AUX II’ etc. are available,
see section 2.9. SPECIAL OPTIONS.
PAGE 2-1
2 INSTALLATION RT2047 DSC - PART I
2.2 MOUNTING POSSIBILITIES
TABLETOP AND DECKHEAD
24889
Mounting bracket H2055
24890
Mounting kit H2068 and H2055
PAGE 2-2
2 INSTALLATION RT2047 DSC - PART I
BULKHEAD AND CONSOLE
24892
Mounting kit H2063
24893
Mounting kit H2062
24891
Mounting kit H2064
IN CONJUNCTION WITH OTHER “S.P. RADIO” EQUIPMENT.
Look up the INSTALLATION section for the S.P. RADIO unit in question.
PAGE 2-3
2 INSTALLATION RT2047 DSC - PART I
2.3 DIMENSIONS AND DRILLING PLAN
UNIVERSAL MOUNTING BRACKET H2055
Permits a wide variety of installation possibilities, such as table top, bulkhead or deck head installation.
Fur other possibilities such as console installation, installation with 19" rack or assembly of all units in
the Compact programme on the bulkhead, see special information concerning installation of the
Compact programme.
115
D
24894A
α
48
132
132
A B C D E F
min. 117
FE
0° 130 48 117 130 48 117
4.8° 142 48 117 146 53 117
9.6° 155 48 118 163 59 116
14.4° 167 45 133 178 65 113
Dimensions in mm.
225
B C
A
132
WEIGHT
Mounting kit H2055 : 1.5 kg
H2054 : 5.5 kg
H2074 : 4.0 kg
CRY2001 : 3.2 kg
RT2047 : 5.2 kg
24897
PAGE 2-4
50 mm
4 pcs ø6.5 mm
4 pcs ø4.5 mm
175 mm
80 mm
10 mm
100 mm
132 mm C/F
2 INSTALLATION RT2047 DSC - PART I
4 pcs M5x8
24896
Mounting kit H2068 and H2055
48
D
132 225
132 132
215
117
B CFE
A
24895
A B C D E F
α
0° 230 67 117 230 67 117
4.8° 243 67 129 245 72 117
9.6° 255 65 142 262 78 115
14.4° 265 62 155 270 89 112
Dimensions in mm.
WEIGHT
Mounting kit H2068 and H2055 : 1.5 kg
H2054 : 5.5 kg
H2074 : 4.0 kg
CRY2001 : 3.2 kg
RT2047 : 5.2 kg
PAGE 2-5
2 INSTALLATION RT2047 DSC - PART I
Mounting kit H2063
min.295
24898
27444A
253mm
4.5mm 4.5mm
16mm
16mm
240mm
4 stk 6mm
4 stk 3.5mm uns for M3 DIN 963
Cutting out 231x100mm
16mm16mm
100mm
113mm
Free distance must be kept to
allow free air circulation ambient
temperature max. 40°C.
WEIGHT
Mounting kit H2063 : 1.0 kg
H2054 : 5.5 kg
H2074 : 4.0 kg
CRY2001 : 3.2 kg
RT2047 : 5.2 kg
4 pcs M3x30
4 pcs cover
8 pcs M5x8
24770
PAGE 2-6
4 pcs M5x30
2 INSTALLATION RT2047 DSC - PART I
Mounting kit H2064
min.295
24772
27447A
20mm20mm
253.00
240.00
4.5mm4.5mm
4 stk ø6mm
4 stk ø3.5mm uns for M3 DIN 963
Cutting out 231x200mm
20mm20mm
200mm
208mm
221mm
Free distance must be kept to
allow free air circulation ambient
temperature max. 40°C.
WEIGHT
Mounting kit H2064 : 1.5 kg
H2054 : 5.5 kg
H2074 : 4.0 kg
CRY2001 : 3.2 kg
RT2047 : 5.2 kg
4 pcs M3x30
8 pcs cover
16 pcs M5x8
24899
4 pcs M5x30
PAGE 2-7
2 INSTALLATION RT2047 DSC - PART I
Mounting kit H2062
min 295
28369
27451
27450
20mm20mm
100mm
4.5mm
225.5mm 225.5mm
4 stk ø6mm
8 stk ø3.5mm uns for M3 DIN 963
Cutting out 451x100mm
2 stk ø3mm
473mm
460mm
Free distance must be kept to
allow free air circulation ambient
temperature max. 40°C.
6mm6mm
10mm10mm
121mm
108mm
WEIGHT
Mounting kit H2062 : 1.5 kg
H2054 : 5.5 kg
20mm 20mm
H2074 : 4.0 kg
CRY2001 : 3.2 kg
RT2047 : 5.2 kg
8 pcs M3x30
8 pcs M3x8
12 pcs M5x8
24773
PAGE 2-8
*
*
2 pcs M3x30
4 pcs M5x30
2 INSTALLATION RT2047 DSC - PART I
2.4 HANDSET
The handset can be placed anywhere near the VHF set. The cable is nine cored and connected to the
rear plate through a 9 pin Sub D connector with lock nuts.
Installation of the cable, see the drawings of the mounting brackets, section 2.3 DIMENSIONS AND
DRILLING PLAN. The cable grommet must be placed in the most convenient groove in the mounting
bracket.
If more than one handset is needed, see section 2.12. and 2.13. in part II, SPECIAL INSTALLATION
WITH 2 OR 3 MICRO TELEPHONES.
2.5 MICROTELEPHONE CONNECTOR
Wiring of the micro telephone connector.
3,1180%(5 )81&7,21
1 Telephone +
2 Ground
3 Ground
4 Microphone
5 Handset key
6 AF from RX buffer
7 Interrupt/Distress cry *
8 Serial input/output
9 +13V Internal/Phone Patch**
*/ Signal selection on jumper P608 on the Interface-unit.
**/ Signal selection on jumper P934 on the Filter-unit
2.6 POWER SUPPLY
The standard power supply for RT2047 is 12V DC .
For 24V DC supply an external power supply N418 ( switch mode ) or the N420 a 24V DC to 13.2V DC
serial regulator can be used, see part II, section 2.14 . and 2.15 .For 110V AC, 127V AC, 220V AC or 237V
AC an external power supply N163S must be used together with N418 or N420 .
2.7 POWER AND EXT. LOUDSPEAKER CONNECTOR
Wiring of the power and ext. loudspeaker connector.
3,1180%(5 )81&7,21
1 +Ext. loudspeaker*
2 No connection
3 +12V Power Supply
4 ON/OFF for 24V Supply
5 -12V Power Supply
6 -Ext. loudspeaker*
*/ If necessary a 4-8 ohm (4 W) external loudspeaker can be connected to pin 1 and 6 of the power
connector J802. External loudspeakers H2054 and H2074 are available for this option.
PAGE 2-9
2 INSTALLATION RT2047 DSC - PART I
2.8 ANTENNAS
All common 50 ohm antennas, which cover the used frequency range with a reasonable standing wave
ratio, maximum 1.5, are applicable.
The antenna is connected to the set by means of a 50 ohm coaxial cable with low loss, e.g. RG213U. At
the cable end a PL259 plug is mounted.
The antenna must be placed as high and as free of obstructions as possible. The horizontal distance to
metal parts must be at least 1.0 metre.
S. P. Radio has an antenna with the necessary specifications available for purchase. The mentioned
antenna is characterised by small external dimensions. See the special brochure ‘VHF AERIALS’ for
particulars.
2.9 SPECIAL OPTIONS
K-SWITCH.
It is possible to change between standard functions and the German river boat functions by installing an
external switch.
SELCALL RELAY.
When the selcall has accepted a CQ or individual call signal, the selcall relay, RE1-9 on the Filter-unit will
turn on and short-circuit two wires, which can be used for remote alarm. Max. contact load: 100V AC/24V
DC - 2A. This option is available on the filter print.
AF TO INFORM. DECODER.
The circuit giving AF signals to the information decoder is turned on when the set has accepted a CQ or
individual call signal. The circuit is turned “ON” or “OFF” like the relay RE1-9. This option can be found
in connector P4-6 on the interface print.
AUX II.
When an information on certain channels is wanted, i.e. controlling a watch keeping receiver, the AUX
II information can be used. A relay RE2-9 on the Filter-unit is controlled through the buffer/inverted U11/
5-6 from the ìC U19-6. Max. contact load: 100V AC / 24V DC - 2A. The AUX II option is available on the
filter print.
OUTPUT TO RECORDER.
Through the connector P4-6 pin 1 and 2 on the INTERFACE UNIT (6) the AF signal to the telephone output
can be led to a tape recorder. This option is located in connector P4-6.
AUX 1
The option AUX I is for-either internal or external use. It is placed in P3-6 pin 1 on the INTERFACE UNIT.
Max. level on the output of the U11-6 must not be more than the battery level, because a diode is
connected to the supply pin in the IC.
DISTRESS CRY / INTERRUPT
Jumper P8-6 on the interface print leads either ‘Distress Cry’ or ‘Interrupt’ through the filter print to the
handset key connector. The Interrupt signal is required when RT2047 is used with the VHF DSC RM2042
and Distress Cry is used for scramblers CRY2001 and CRY2002.
PHONE PATCH / +13V
Jumper P34-9 is used for selecting if The ‘Phone Patch’ signal or if ‘+13V’ should be led to the handset
key connector. +13V is required when RT2047 is used with the VHF DSC RM2042 and Phone Patch is
used for the Phone Patch unit H2047.
PAGE 2-10
2 INSTALLATION RT2047 DSC - PART I
2.10 REAR VIEW OF VHF RT2047
Screws for Tx Power Transistor
T401’s heat sink conductor.
28368
Power Supply
connector P802
Cable groove for
special options
12V DC
Screws for Regulator Transistors
heat sink on Interface unit(6).
MUST BE REMOVED WHEN INTERFACE
UNIT HAS TO BE REMOVED!
Microtelephone
connector J803
Antenna
connector J801
PAGE 2-11
2 INSTALLATION RT2047 DSC - PART I
2.11 STANDARD FREQUENCY TABLE
&+$11(/ 75$160,77,1*
)5(48(1&<0+]
01 156.050 160.650 156.050
02 156.100 160.700 160.700
03 156.150 160.750 160.750
04 156.200 160.800 160.800
05 156.250 160.850 156.250
06 156.300 156.300 156.300
07 156.350 160.950 156.350
08 156.400 156.400 156.400
09 156.450 156.450 156.450
10 156.500 156.500 156.500
11 156.550 156.550 156.550
12 156.600 156.600 156.600
13 156.650 156.650 156.650
14 156.700 156.700 156.700
15 156.750 156.750 156.750
16 156.800 156.800 156.800
17 156.850 156.850 156.850
18 156.900 161.500 156.900
19 156.950 161.550 156.950
20 157.000 161.600 161.600
21 157.050 161.650 157.050
22 157.100 161.700 157.100
23 157.150 161.750 157.150
24 157.200 161.800 161.800
25 157.250 161.850 161.850
26 157.300 161.900 161.900
27 157.350 161.950 161.950
28 157.400 162.000 162.000
60 156.025 160.625 160.625
61 156.075 160.675 160.675
62 156.125 160.725 160.725
63 156.175 160.775 156.175
64 156.225 160.825 160.825
65 156.275 160.875 156.275
66 156.325 160.925 156.325
67 156.375 156.375 156.375
68 156.425 156.425 156.425
69 156.475 156.475 156.475
70 156.525 156.525 156.525
71 156.575 156.575 156.575
72 156.625 156.625 156.625
73 156.675 156.675 156.675
74 156.725 156.725 156.725
77 156.875 156.875 156.875
78 156.925 161.525 156.925
79 156.975 161.575 156.975
80 157.025 161.625 157.025
81 157.075 161.675 157.075
82 157.125 161.725 157.125
83 157.175 161.775 157.175
84 157.225 161.825 161.825
85 157.275 161.875 161.875
86 157.325 161.925 161.925
87 157.375 161.975 161.975
88 157.425 162.025 157.425
WX1 Inhibit 162.550 162.550
WX2 Inhibit 162.400 162.400
WX3 Inhibit 162.475 162.475
WX4 Inhibit 161.650 161.650
5(&(,9,1*)5(48(1&<0+]
INT’L MODE
(INT-CHANNELS)
US MODE
(A-CHANNELS)
PAGE 2-12
RT2047 DSC - PART II
CONTENTS
1 GENERAL INFORMATION 1-1
1.1 GENERAL DESCRIPTION 1-1
1.2 TECHNICAL DATA 1-2
1.3 CONTROLS 1-3
1.4 PRINCIPLE OF OPERATION 1-5
1.4.1 FREQUENCY GENERATION 1-5
1.4.2 RECEIVER 1-5
1.4.3 TRANSMITTER 1-5
1.4.4 THE MICROCOMPUTERS 1-5
1.5 BLOCKDIAGRAM 1-7
9546
RT2047 DSC - PART II
1 GENERAL INFORMATION
1.1 GENERAL DESCRIPTION
RT2047 can operate in duplex and simplex mode.
RT2047 is provided with built in duplex-filter for duplex communication with one antenna.
RT2047 includes all 55 international and U.S. VHF marine channels, and is prepared for up to 20 private
channels to be selected as simplex or duplex channels. As option up to 67 private channels can be
provided.
RT2047 has six scanning programmes, one standard programme, and 5 individually programmable
scanning programmes.
RT2047 has built in dual watch facility, which enables the operator to listen to two channels simultaneously (the selected channel and a preference channel - normally CH16.)
RT2047 is provided with quick selection of channel 16.
RT2047 is provided with selcall decoder. Selective calls (CALL) or all ships calls (CQ) from the coast
station will be decoded.
RT2047 receiver section is a double-conversion superheterodyne system, which makes use of a phase-
locked digital frequency synthesizer for frequency generation based on a single crystal to provide all the
standard channels and the private channels.
RT2047 transmitter section is a phase-locked phase-modulated signal generator with a solid state RF
power amplifier.
RT2047 is provided with two microcomputers, one for controlling the frequency synthesizer, reading from
and to EEPROMS, controlling the squelch and volume functions, and controlling the selcall filter. The
other µC is controlling the display drivers, the dual watch and scanning functions.
RT2047 is for 12 Volt DC supply. Voltage change-over from 24V to 12V is done by the switch-mode power
supply N418.
RT2047 employs the most modern circuit technology, housed in a corrosion resistant aluminium cabinet
with a green nylon finish.
RT2047 is provided with membrane switches for controls, easy to use, reliable and hard-wearing. Cutouts in the metal front serve as a safe finger-guide.
RT2047 is fitted with night illumination.
RT2047 has been prepared with a serial communication interface for DSC (Digital Selective Call)
operation together with S.P. RADIO’s VHF DSC RM2042. DSC is the globally adopted general purpose
system for selective calling in the ship-to-ship, ship-to-shore and shore-to-ship directions and can best
be compared to ordinary telephony, giving you direct access to the national telephone network in those
areas where the coast stations have the automatic services. DSC also enables you to make automatic
distress calls containing the ships position etc. complying with the international requirements stated by
IMO in the Global Maritime Distress and Safety System, known as GMDSS.
RT2047 is prepared for scrambled communication in conjunction with Scramblers CRY2001 or
CRY2002, both produced by A/S.
9543
PAGE 1-1
1 GENERAL INFORMATION RT2047 DSC - PART II
1.2 TECHNICAL DATA
VHF RT2047 fulfils the International CAPT regulations.
GENERAL SPECIFICATIONS
All international maritime VHF channels
Private Channels 20 as option up to 67
Operation Duplex and Simplex
Modulation G3EJN (Phase)
Antenna Impedance 50 ohm
Frequency Stability +/- 10 ppm
Temperature Range -20 C to +55 C
Nominal Power Supply 13.2V DC
Power Supply Variation 12V DC -10% to +30%
(with reduced data according to
international standards)
Power Consumption Standby = 0.5 Amp.
Transmit = 6 Amp.
Dimensions Height: 115 mm
Width: 225 mm
Depth: 262 mm
RECEIVER
Frequency Range Simplex 155.400 - 158.000 MHz
Frequency Range Duplex 160.000 - 162.600 MHz
Sensitivity 0.35 uV pd at 12 dB SINAD
Duplex desensitisation Less than 2 dB
AF Output Power 3 Watt/4 ohm
Telephone Output 0.45V RMS/200 ohm
Distortion Less than 5%
Scanning Facilities 5 scanning programmes with
possibility for all your
channels in each programme
except the private channels
from P20 to P67
Selective Call Decoder According to CCIR
TRANSMITTER
Frequency Range 155.400 - 158.000 MHz
RF Output Power 25 Watt, +0 to -1 dB
Reduced RF Output 0.5 to 1 Watt
Distortion Less than 2%
PAGE 1-2
9543
1 GENERAL INFORMATION RT2047 DSC - PART II
1.3 CONTROLS
23990
Press
Press
Press
Scan DW USA CQ
Duplex Shift Call
Vol SQ Tx1W
OFF
STOP
RUN
ON
Turns the set on or off.
OFF
VOL
ON
Increases volume progressively in 16 steps.
VOL
Reduces volume progressively in 16 steps.
SQ
16
SQVOL VOL
SHIFT
SCAN
SCAN
ADD
1
SCAN
PROG
SCAN
TIME
4
SELCALLSELCALL
TESTRESET
7
USA DIM
0
SCAN
DELETE
2
D.W.
5
1W
8 9
P
ENT
3
6
Press
Press
Press
Press
Press
Press
Press
Press
SQ
Increases squelch sensitivity progressively in 8 steps, a gradual exclusion of weak
signals with atmospherics.
SQ
Reduces squelch sensitivity progressively in 8 steps.
STOP
Stops and starts scanning sequence. Listen on several predetermined channels.
RUN
Quick select of the call and distress channel 16.
16
Digits from 1 to 0.
1
Selects private channels.
P
ENT
Terminates the keying in of selected channels, scanning programmes, scan time etc.
Activates the functions marked in orange on the keyboard.
SHIFT
9543
PAGE 1-3
1 GENERAL INFORMATION RT2047 DSC - PART II
SHIFT FUNCTIONS
SCAN
Press
Press
Press
Press
Press
Selects scanning programmes.
SCAN
ADD
Adds a channel to the scanning table.
SCAN
DELETE
Deletes a channel from the scanning table.
SCAN
PROG
Stores the current scanning programme in the memory.
SCAN
TIME
Selects the scan time from 1 to 99 seconds. The time chosen will be used to listen
on one of the secondary channels receiving a signal.
D.W.
Press
Press
Selects the dual watch facility.
SELCALL
RESET
Resets the selcall decoder after a call.
SELCALL
Press
Press
Press
Press
TEST
Tests the selcall decoder.
1W
Selects 1 W reduced power output.
USA
Selects the VHF channels used in USA.
DIM
Switches the panel illumination on or off.
Note: See the VHF RT2047 Operating Manual for functional description.
PAGE 1-4
9543
1 GENERAL INFORMATION RT2047 DSC - PART II
1.4 PRINCIPLE OF OPERATION
1.4.1 FREQUENCY GENERATION
The frequencies are generated from a crystal oscillator operating on 21 MHz. The 21 MHz is divided in
the REFERENCE DIVIDER to 2.1 MHz which is the input to the RX-REFERENCE DIVIDER and also the
clock-signal for the microcomputer on the Interface Unit. In the RX-REFERENCE DIVIDER the 2.1 MHz
is divided by 168 to 12.5 KHz which is reference for the PHASE DETECTOR. This makes it possible to
change the frequency from the RX-VCO with 12.5 KHz intervals.
The signal from the RX-VCO is divided in a PRESCALER which divides by 33 until the A-COUNTER has
reached zero and then it divides by 32. The N-COUNTER divides the output from the PRESCALER, and
the output is led to the PHASE-DETECTOR, and here it is compared with the 12.5 KHz. If there is a
difference an error voltage will be generated. This is integrated in the LOOP-FILTER and the output of
this filter controls the RX-VCO. The frequency of the RX-VCO is the receiving frequency minus the
intermediate frequency.
f
LO1
= fRX - f
= fRX -21.4 MHz
1IF
The output from the RX-VCO is mixed with the output from the TX-VCO which is in lock when it is 16.8
MHz above the RX-VCO. This means that the receiver always is 4.6 MHz above the transmitter, namely
21.4 - 16.8 = 4.6; and this difference is equal to the duplex distance. The 16.8 MHz from the MIXER is
divided by 32 to 525 KHz, which is compared with the 21 MHz divided by 40 in the REFERENCE DIVIDER.
The error voltage is integrated in the LOOP-FILTER, and the output of this filter controls the TX-VCO.
1.4.2 RECEIVER
The antenna-signal is led through the duplex-filter and the antenna relay to the RF-AMPLIFIER. The
bandpass filters are tuned by means of capacitor-diodes which are controlled by means of a DC-voltage
which is derived from the control-voltage to the RX-VCO. In the FIRST MIXER the antenna signal is mixed
with the output from the RX-VCO to the intermediate frequency 21.4 MHz. In the integrated IF circuit, the
first IF frequency on 21.4 MHz is mixed with a crystal oscillator signal on 20.945 MHz to reach the second
IF frequency on 455 kHz. This signal is filtered in the ceramic filter, before it is amplified and detected in
the integrated IF-circuit. The audio frequency signal is amplified and led through an active filter providing
the frequency response further to the telephone amplifier and the AF power amplifier.
1.4.3 TRANSMITTER
The microphone signal is led through the MICROPHONE AMPLIFIER where the necessary amplification,
limiting, and filtering takes place. The limiting is done by a clipper. The signal from the MICROPHONE
AMPLIFIER is led to the LOOP-FILTER, where the phase modulation of the transmitter takes place. As
the TX-VCO oscillates directly on the transmitting frequency, the signal only has to be amplified. This is
done in the TX-BUFFER, PA-DRIVER, and the PA-POWER AMPLIFIER. The power supply for the PAdriver is adjustable, and is used for adjusting the output power. The harmonics of the output is filtered in
HARM-FILTER , before it is led through the ANTENNA-RELAY and the DUPLEX-FILTER to the antenna.
1.4.4 THE MICROCOMPUTERS
The µC on the Interface Unit is taking care of calculating the dividing figure for the synthesizer, reading
from and to the EEPROMs, controlling the squelch and volume functions, and controlling the selcall filter.
The µC on the Keyboard Unit is taking care of the keyboard scanning, the input from the handset key and
the display drivers as well as the Dual Watch and Scanning functions. The keyboard µC is also handling
the serial SP VHF-BUS communication with external devices such as the VHF DSC - RM2042. The
communication between the two µC’s is accomplished by a RS232C -type serial connection.
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1 GENERAL INFORMATION RT2047 DSC - PART II
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