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.

3,1180%(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.

3,1180%(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.

9543

PAGE 1-5

1 GENERAL INFORMATION RT2047 DSC - PART II

PAGE 1-6

9543

1 GENERAL INFORMATION RT2047 DSC - PART II

Phase
Detector

Rx-Reference
Divider

Rx VCO

Loop
Filter

÷168

÷33/32
Prescaler

7 bit
A-counter N-counter

10 bit

Control-logic

Mixer

Second 455 kHz IF

and Detector

First
Mixer

21.4 MHz IFRF-AMP

Mixer

16.8 MHz
÷32

Filter

Loop Phase/Freq.

Detector

Reference
Divider

Tx-Buffer Tx-VCO

X-Tal
Oscilllator
21 MHz

PA-Driver

PA-Power
AMP

Harm
Filter

+13V

fTx

+

-

16.8 MHz

525 kHz

2.1 MHz

fLO1

fRx

f2IF AF

PA-Reg

+ Distress

SQ-Filter Rectifier Comparator

AF-Mute

EEPROM

Delayed OFF

+10V Sensor

Buffer +
Rx/Tx

+10V Tx

Delay Driver

+10V VCO
ON/OFF

AUX II Relay
Cry

AUX I
Driver

Battery
Sensor

D/A
Converter

6dB/Octave
Filter

Telephone
AMP

Vol­Attenuator

AF-Power
Amplifier

AF from Rx
Buffer

MIC.-AMP.

Integrator

MIC. + AMP.
Clipper

MIC.-AMP.

Pre-Empaasis

Selcall Relay
+AF to inform.
Decoder

+5V +10V KEY-Buffer

Detector

÷2

able
Counter

AMP/Limiter

Filter

Switched
Bandpass

Capacitor

Programm-

ON/OFF

Rx-Filter
Control-AMPFilter

Duplex

Serial
Interface
Buffers

Display
Driver

nication

Commu-

Serial

Driver

Interrupt
CircuitGenerator

Constant
Current

Interface

Display

LCD-

Loudspeaker

uC

Int

Reset

2.1MHz

2.1MHz

+13V

+10V

+10V

+13V

+13V +5V

+10V+13V

MIC. IN

TELEPHONE OUT

AF FROM Rx

HANDSET KEY

SERIAL DATA

INTERRUPT

+13V +5V

Seriel
Interface
Buffers

uC

Int.

+13V PS

-13V PS

PATCH
INPUT

+13V +13V

1

1

1

1

1

1

2

8
9

5

4

7

5

48

3

9

Antenna
Relay

Control

Filter

+5V Keyboard

Buffer

24312D

3

3

AUX LS

PHONE

ON/OFF to
24V Supply

20.945 MHz

(MODULE 200)

INTERFACE (MODULE 6)

KEYBOARD (MODULE 7)

Tx-EXCITER (MODULE 300)

RECEIVER (MODULE 100)

PA-AMPLIFIER

Rx-SYNTHESIZER

(MODULE 400 & 500)

1.5 BLOCKDIAGRAM

9543

PAGE 1-7

RT2047 DSC - PART II

CONTENTS

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

9546

2 CIRCUIT DESCRIPTION RT2047 DSC - PART II

2 CIRCUIT DESCRIPTION

2.1 RECEIVER UNIT MODULE 100

The receiver unit includes the following circuits:

2.1.1 RF-AMPLIFIER AND FIRST MIXER

The RF-amplifier working in the frequency range 155.4 MHz to 162.4 MHz consists of the transistor Q101
and the two double-tuned filters surrounding it. The signal is led from the aerial through the duplex-filter
to the antenna switch and from there to the receivers input-filter. The input filter and the intermediate filter
are variable capacitance tuned filters, controlled by a DC-voltage derived from the RX-VCO control
voltage. This secures an optimal filter response within the receivers frequency range. The two double­tuned filters create the necessary attenuation of signals distant from the wanted signal frequency in order
to give the wanted spurious rejection of such unwanted signals. The amplifying transistor Q101 (which
is a large current, low noise transistor in a common-base configuration) secures by its gain the receiver
overall noise figure and a good two-signal performance. The RF-input to the first mixer is taken from the
coil L104 in the intermediate filter. Mixer transistor Q102 is of the JFET-type, where the first LO-signal
is injecting into the source from a 50 ohm generator. The wanted 21.4 MHz IF-output is selected by means
of the tuned drain circuit consisting of L105, C117, C119, and R110 which also creates the necessary
impedance matching the IF-crystal filter.

2.1.2 IF-FILTER AND AMPLIFIER

The receivers adjacent channel selectivity is maintained by means of the crystal filter FL101. The output
from this filter is led to the IF-amplifier with the transistor Q103, L106, C123, and R112 giving the
appropriate impedance matching the filter output. The amplifier gives the needed power gain between
the crystal filter and the second mixer and also secures good large signal performance.

2.1.3 SECOND MIXER, CERAMIC FILTER, DETECTOR AND AF AMPLIFIER

The integrated IF circuit includes the second mixer, the limiting amplifier and the detector with post AF
amplifier.

The second local oscillator signal is generated by means of the integrated oscillator and an external
crystal X101, running on 20.945 MHz. The signal out of the second mixer (455 kHz) is fed through the
ceramic filter FL102 to the limiting amplifier and discriminator in U101.
The quadrature phase discriminator includes the external phase shift network consisting of the tank circuit
with L108, C129 and R120.
The AF output from the detector is amplified by means of an internal operational amplifier and finally
buffered by means of the discreet transistor amplifier with Q104.

2.1.4 IF POWER SUPPLY

The integrated IF circuit and AF buffer amplifier are powered from an integrated 5V series voltage
regulator U102. The input voltage for this circuit is the receiver 10V supply.

9543

PAGE 2-1

2 CIRCUIT DESCRIPTION RT2047 DSC - PART II

COMPONENT LOCATION RECEIVER UNIT MODULE 100

View from component side View from component side
with upper side tracks. with lower side tracks.

32127B

PAGE 2-2

9641

2 CIRCUIT DESCRIPTION RT2047 DSC - PART II

DIAGRAM RECEIVER UNIT MODULE 100

AC voltages outside frame of diagram.

: Measured with oscilloscope or frq. counter.

: Measured with test probe.

: Connections to module.

[ ] : Approx. measurement with test probe.

Test conditions:
Voltages without brackets:
Antenna signal 1 mV pd:

Df= +3 kHz; f

= 1 kHz

m

Voltages in brackets:
Antenna signal 10 mV pd:

Df = + 3 kHz; f

= 1 kHz

m

This diagram is valid for PCB rev. 32127B.

9641

PAGE 2-3

2 CIRCUIT DESCRIPTION RT2047 DSC - PART II

2.2 RX-SYNTHESIZER UNIT MODULE 200

The RX-synthesizer unit includes the following circuits:

2.2.1 RX-VCO AND BUFFER AMPLIFIERS

The transistor T203 is producing 8.3 V supply voltage for the RX-VCO and bias for the buffer amplifiers
consisting of the transistors T201 and T204. The RX-VCO comprises a Field Effect Transistor T202 (the
oscillator transistor), two coaxial coils L203, L204, two capacitors C212, C214, and a variable capacitance
diode D201. The frequency is mainly determined by the components L203, L204, C214, and D201. The
RX-VCO is a voltage controlled oscillator where the control voltage from the loop filter determines the
frequency by means of D201. A high control voltage to the variocap. diode D201 means a small
capacitance in the diode which means a high frequency of the VCO. In the opposite way a low control
voltage means a low VCO frequency. The RX-VCO signal is passed to two buffer amplifiers via low pass
filter C209, C206, L201. The L01 buffer transistor T201 is producing 5 mW for the 1st mixer in the receiver.
The 5 mW is taken from the tuned filter L202, R202, C207, and C208. The prescaler buffer transistor T204
is producing 0.25 mW for the 16.8 MHz mixer in the TX-Exciter-Unit. It is also producing signal for 32/33
prescaler. The signal from transistor T204 is led through a low pass filter C217, L206, and C222. The gain
in both buffers can be adjusted by the potentiometer R209.

2.2.2 32/33 PRESCALER

The integrated circuit IC201 is a two modulus prescaler based on the ECL technique. From the control
logic in the programmable divider IC202 pin 14, a high or low level is led to the prescaler IC201 pin 1. A
high level at IC201 pin 1 causes the prescaler to divide by 33 and in turn a low level at pin 1 sets it up for
dividing by 32. The resistor R232 and the diode D204 work as a speed-up circuit.

2.2.3 THE PROGRAMMABLE DIVIDER

The programmable divider IC202 contains two phase detectors, a lock detector, a reference divider, an
A-counter, a N-counter, control logic, and 8 latches. Only phase detector B of the detectors is in use. When
the VHF is switched on the microcomputer will load dividing figures into the reference divider and into the
A and N-counters. The microcomputer loads only one latch at a time.
By setting up a code at the address inputs Al - A2 the microcomputer selects a latch and at the same time
a code for the dividing figure is set up at the data inputs D0 - D3. The microcomputer sends a strobe pulse
to IC202 pin 12 and the selected latch is loaded. The procedure is then repeated until all the latches are
loaded.
When the channel or the function of the VHF is changed it is only the latches for the A and N-counter that
change data. The reference frequency is 2.1 MHz and it is constant. Therefore it is not necessary to
change the dividing figure every time.
In the beginning of a counting period the prescaler IC201 starts dividing by 33 and the A and N-counters
count down. First the A-counter reaches zero and stops counting and the control logic shifts the prescaler
to divide by 32. Then the N-counter reaches zero and sends a pulse to the phase detector B, and the
control logic shifts the prescaler to divide by 33. The control logic also reloads the A and N-counters with
data from their latches and the whole procedure starts from the beginning.
The pulse frequency from the reference divider is 12.5 KHz. If the RX-VCO frequency is correct the pulse
frequency of the N-counter is also 12.5 KHz and in phase with the pulse from the reference divider. The
phase detector B compares the phase of the two pulses. If they are not in phase the detector sends
correction pulses to the phase-detector-pump for correcting the frequency/phase of the RX-VCO.
However, the synthesizer circuit is born with a small phase error, therefore the phase detector is sending
small correction pulses to transistor T210 with a frequency of 12.5 KHz.

PAGE 2-4

9543

2 CIRCUIT DESCRIPTION RT2047 DSC - PART II

2.2.4 PHASE DETECTOR PUMP AND LOOP FILTER

We assume that the RX-VCO frequency has decreased from its nominal frequency, The phase-detector
now sends negative correction pulses from IC202 pin 17 to T210, which goes on. A current will then flow
from C225 through R225 and R229 and into T210. This current will discharge C225 forcing the output
voltage from the transistors T205 and T206 to increase until the VCO reaches the correct frequency. If
the RX-VCO frequency is too high, the negative correction pulses from the detector at pin 16 of IC202
will turn transistor T209 off. The collector voltage of transistor T209 increases and a current will flow
through the diode D202, the resistor R225 and into the capacitor C225 and charge this capacitor. The
output voltage at the collector of the transistors T205 and T206 will decrease until the VCO reaches its
right frequency. If the phase-locked-loop is locked, both outputs of the phase-detector will be 5 V and the
output voltage of the transistors T205 and T206 will have a value between 2 V and 10 V corresponding
to the VC0-frequency. However, the system is working with a constant phase error and the phase detector
sends small correction pulses to transistor T210, even the phase-locked-loop is locked. The four
transistors T205, T206, T207, and T208 are working as an operational amplifier with the inverting input
at base of transistor T208. Non-inverting input is at transistor T207 while the transistors T205 and T206
forms the output stage.

9543

PAGE 2-5

2 CIRCUIT DESCRIPTION RT2047 DSC - PART II

COMPONENT LOCATION RX-SYNTHESIZER UNIT MODULE 200

View from component side View from component side
with upper side tracks. with lower side tracks.

23694D

PAGE 2-6

9543

2 CIRCUIT DESCRIPTION RT2047 DSC - PART II

DIAGRAM RX-SYNTHEZISER UNIT MODULE 200

AC voltages outside frame of diagram.

: Measured with oscilloscope or frq. counter.

: Measured with test probe.

: Connections to module.

[ ] : Approx. measurement with test probe.

Test conditions:
Voltages without brackets:
Antenna signal 1 mV pd:

Df= +3 kHz; f

= 1 kHz

m

Voltages in brackets:
Antenna signal 10 mV pd:

Df = + 3 kHz; f

= 1 kHz

m

This diagram is valid for PCB rev. 23694D.

9543

PAGE 2-7

2 CIRCUIT DESCRIPTION RT2047 DSC - PART II

2.3 TX-EXCITER UNIT MODULE 300

The TX exciter unit contains the following circuits:

2.3.1 INSULATION BUFFER AND 16.8 MHZ MIXER

From RX-VC0 the signal is led to transistor T301 and from TX-VC0 the signal is led to transistor T302.
The transistors are not coupled with common base and act as buffer amplifiers. The mixed signal over
resistor T305 is led to the mixer amplifier T303 via capacitor C305. The differential signal which is the TX­VC0 frequency minus the RX-VC0 frequency is led to the amplifier transistor T304 through the low-pass
filter consisting of C310, L301 and C311. In transistor T305 the signal is amplified to TTL level. The diode
D301 works as a base clamp diode.

2.3.2 THE 21 MHZ OSCILLATOR

The oscillator is a Colpitt type and the oscillator transistor T308 is oscillating by means of a 21 MHz crystal
X301.
The trimmer capacitor C331 is for fine adjustment of the oscillator frequency.
RF signal for the reference divider is led to transistor T307 for amplifying. In transistor T306 the signal
is amplified to TTL level.

2.3.3 PHASE/FREQUENCY DETECTOR, 32 COUNTER AND REF. DIVIDER

The crystal frequency is led to IC306 pin 10 which is a decade counter. From output pin 5 of this, the
frequency is divided by 5. This frequency is led to flip-flop IC305a, where the frequency is divided by 2.
From IC305a pin 5, the 2.1 MHz is taken and this is the clock frequency for the microcomputer and the
RX synthesizer. The resistor R322 is for pull-up and the ferrite bead FP301 is blocking for higher
harmonics of the clock frequency.
From IC306 pin 8, the 21 MHz is also divided by 10. The frequency is divided by 2 in flip-flop IC305b and
divided by 2 in IC304a. At IC304b pin 13, the 21 MHz is then divided by 40 and the frequency is therefore
525 KHz at which the phase detector is working.
From the other side the mixed signal of 16.8 MHz is led to the binary divider IC301 pin 10 where it is divided
by 16. In flip-flop IC302b the signal is divided by 2. From IC320b pin 8 the 16.8 MHz is then divided by
32 giving 525 KHz.
The phase/frequency detector consists of IC302a, IC303, and IC304b. From IC304b pin 9 the detector
is connected to the loop filter via the pull-up resistor R321 and the diode D303. The phase corrections
pulse from the detector is active low and when the phase locked loop is in lock the duty cycle of the
correction pulse is about 30 per cent.

THE CORRECTION PULSES:

After the count down of the 21 MHz the IC304b pin 9 goes low. Pin 8 goes high and this is connected to
IC303 pin 2. When the 16.8 MHz is divided by 32 the IC302a pin 6 and IC303 pin 1 go high. When IC303
pin 13 is always high the IC303 pin 8 will go low and preset IC302a and IC304b; the correction pulse will
then go high and so on. The propagation delay in the two inserters IC303 determines the size of the preset
pulse.

PAGE 2-8

9543

2 CIRCUIT DESCRIPTION RT2047 DSC - PART II

2.3.4 TX-VCO

The TX-VCO comprises a Field Effect Transistor T311 (oscillator transistor), two coaxial coils L309 and
L310, the capacitors C343 and C345, and a variocapacitor diode D302.
The frequency is mainly determined by L309, L310, C345, and D302. The TX-VCO is a Voltage Controlled
Oscillator, where the control voltage from the loop filter determines the frequency by means of the
variocapacitor diode D302. A high voltage to D302 means a smaller capacitor in D302 and again a higher
VCO frequency. In the opposite way a small control voltage means a smaller frequency.
From drain of transistor T311 the signal is led to a buffer amplifier T310 via a tuned filter consisting of L308,
R342, and C342. The ferrite bead is blocking for UHF oscillating. In the collector of T310 there is a tuned
filter consisting of L307 and C340. From here the signal for two circuits is taken.
From an output on coil L307 the signal to the TX-buffer is taken through capacitor C338. Here the TX­VCO signal is amplified in transistor T309. In the drain of T309 there is a tuned filter consisting of L306,
C332, C333, R332, and R333, which gives a 50 ohm generator for the Power Amplifier Unit. The output
power from the TX-buffer is 25 mW and is adjusted by trimmer potentiometer R341.
Stop and start of both TX-buffer and TX-VCO are controlled from the microcomputer by controlling the
supply for the transistor. This secures that the frequency is correct before the transmitter is started. From
the collector of T310 the signal for the 16.8 MHz Mixer is taken via capacitor C341.

2.3.5 LOOP-FILTER

The Loop-filter amplifier is a differential amplifier (OP-Amp.) with the inverted input at the base of
transistor T314, where also the phase detector is connected. The base of transistor T313, which is the
non inverted input, is connected to +5V by means of R349 and R350. Transistor T312 is the output stage,
and the control voltage for TX-VCO is taken over the resistor R346 and is filtered in the ripple-filter
consisting of R345, C348, C347, and R344. At the input R351 and C352 are working as a filter against
the higher harmonics in the phase detector pulse.
We assume that the system is in lock. While the detector pulse is low a current is flowing out of the
capacitor C351 and the output voltage over R346 increases. The TX-VCO frequency is also increasing
until the detector pulse goes high again. Because the diode D303 is blocking, a current flows into C351
through the resistors R354 and R355. The control voltage over R346 decreases and the frequency is also
decreasing. The current which is flowing in and out of C351 is equal when the system is in lock. For
principal understanding accept that C353 and R352 have no influence on the current to C351.
If the TX-VCO frequency is too high, the detector pulse gets smaller and that means that more current
is flowing into C351 than out. That means again that the control voltage and the frequency will decrease
until the frequency is correct again.
The opposite process will happen if the frequency is too low. Even though the system is in lock there is
always a little phase error. The AF modulation signal is led into the Loop-filter via resistor R356. The
control voltage is then modulated which will modulate the phase in the TX-VCO again.

9543

PAGE 2-9

2 CIRCUIT DESCRIPTION RT2047 DSC - PART II

COMPONENT LOCATION TX-EXCITER UNIT MODULE 300

View from component side with upper side tracks.

View from component side with lower side tracks.

23695D

PAGE 2-10

9543

2 CIRCUIT DESCRIPTION RT2047 DSC - PART II

DIAGRAM TX-EXCITER UNIT MODULE 300

AC voltages outside frame of diagram.

: Measured with oscilloscope or frq. counter.

: Measured with test probe.

: Connections to module.

[ ] : Approx. measurement with test probe.

Test conditions:
Voltages without brackets:
Antenna signal 1 mV pd:

Df= +3 kHz; f

= 1 kHz

m

Voltages in brackets:
Antenna signal 10 mV pd:

Df = + 3 kHz; f

= 1 kHz

m

This diagram is valid for PCB rev. 23695D.

9543

PAGE 2-11

2 CIRCUIT DESCRIPTION RT2047 DSC - PART II

PAGE 2-12

9543

2 CIRCUIT DESCRIPTION RT2047 DSC - PART II

2.4 TX-POWER AMPLIFIER MODULE 400

The TX-power-amplifier includes the amplifier and a harmonic filter.

2.4.1 TX-POWER-AMPLIFIER

The amplifier consists of a single transistor output amplifier and a two transistor power driver. The
transistors are both tuned classic amplifier circuits. The amplifier is made on double sided epoxy board,
using micro strip technique in the tuning circuits. The power driver is fed from a 50 ohm generator with
a power level of 25 mW. The final output power level is controlled by means of the supply voltage level
fed to the power driver. In full power mode, the power driver will deliver about 4.5 - 5 W to the output
transistor T401. The output signal is fed to the harmonic filter through capacitors C405 and C406.

2.4.2 HARMONIC FILTER

The harmonic filter is realised as a seventh-order Chebyschev-filter, which at the same time will provide
the necessary attenuation of the harmonics generated by the power amplifier and a low insertion loss at
the carrier frequency. The output from the harmonic filter is fed to the antenna relay.

2.5 ANTENNA RELAY (500)

The antenna relay, RE501, is placed in the Tx-power amplifier module (400).
The relay is equipped with 2 change-over contacts and is activated when the transmitter is keyed.
In simplex receiving mode the RF signal is led to the receiver (100) through both contacts from the Tx-

section of the duplex filter.
In simplex or duplex transmitting mode the Tx-signal is led from the harmonic filter through a pin to the

Tx-section of the duplex filter.
The other pin is grounded.

9543

PAGE 2-13

2 CIRCUIT DESCRIPTION RT2047 DSC - PART II

COMPONENT LOCATION TX-POWER AMPLIFIER MODULE 400
AND ANTENNA RELAY (500)

View from component side with upper side tracks.

View from component side with lower side tracks.

PAGE 2-14

9619

2 CIRCUIT DESCRIPTION RT2047 DSC - PART II

DIAGRAM TX-POWER AMPLIFIER MODULE 400
AND ANTENNA RELAY (500)

AC voltages outside frame of diagram.

: Measured with AF voltmeter.

Test conditions.
Voltages without brackets:
Operating in Rx position.
With antenna signal 1 mV EMF:

+3 KHz; fm = 1 KHz

f=
Voltages in brackets:
No antenna signal, squelch max.
closed.

Df = + 3 KHz; f

= 1 KHz

m

This diagram is valid for PCB rev. 23973B

9543

PAGE 2-15

2 CIRCUIT DESCRIPTION RT2047 DSC - PART II

PAGE 2-16

9543

2 CIRCUIT DESCRIPTION RT2047 DSC - PART II

2.6 INTERFACE UNIT MODULE 6/600

2.6.1 ON/OFF FUNCTION

ON

When the ON/OFF push button is activated Q4-6 is turned on and the relay RE3-6 is engaged. When the
µC leaves reset condition PC5 is set to high level and Q5-6 will be conducting, keeping Q4-6 on.

OFF

When the ON/OFF push button is activated again U19-6 receives a message on the serial interface. Then
it stores the actual settings of the channel, volume, squelch, power level, INT/USA mode and scan time.
Afterwards PC5 is turned low, and Q5-6, Q4-6, and RE3-6 will switch off.

2.6.2 BATTERY SENSOR

If the battery voltage drops below approx. 9.5V the output of U7/3-6 goes high, and the µC will switch off
the set.

2.6.3 DELAYED OFF

If the ON/OFF push button is kept activated longer than approx. 3 seconds, pin 12 on U12/2-6 will go low
forcing the µC into reset. This means that as soon as the button is released the set will switch off.

2.6.4 TEMPERATURE SENSOR

Not mounted.

2.6.5 5V SUPPLY

The 5V power supply is an integrated, non adjustable regulator.

2.6.6 10V SUPPLY

The 10V supply is a serial regulator with current limiter. When it is switched on Q10-6 gets base current
through R32-6 and R41-6. Thus Q10-6 draws collector current so that Q9-6 turns on and the output
voltage rises. When Q13-6 begins to conduct the current in Q10-6 is reduced. Thus the base current in
Q9-6 is also reduced and the output voltage stabilises . The current limiting starts when the voltage across
R40-6 is big enough to turn Q6-6 on and makes the current flow through D8-6 to the emitter of Q10-6,
and therefore the current in Q10-6 and also in Q9-6 will decrease which results in a decrease of the output
voltage.

9543

PAGE 2-17

2 CIRCUIT DESCRIPTION RT2047 DSC - PART II

2.6.7 PA REGULATOR

By means of the PA regulator it is possible to adjust the output power of the transmitter. When the output
from U3/2-6 is changed from O to 5V, Q7-6 is turned off. Thus Q8-6 is turned on and then also Q2-6 and
Q1-6 and the output voltage rises. When the voltage at the base of Q8-6 is equal to the voltage on the
base of Q7-6 the current in Q8-6 is reduced and then also in Q2-6 and Q1-6 and the output voltage
stabilises. The output power from the TX POWER AMPLIFIER is adjusted by changing the output voltage
of the PA REGULATOR with R68-6. When reduced output power is chosen (0W mode) the µC turns PB5
to 0 V and the reference voltage to the regulator will be lowered. It can be adjusted at R29-6, and thus
also the reduced output power.

2.6.8 RX FILTER CONTROL AMPLIFIER

The control voltage from the RX VCO is turned into a control voltage to the capacity diodes in the band
pass filters in the receiver.

2.6.9 MICROPHONE AMPLIFIER

The amplifier consists of three stages. In the first stage the signal is preemphasized. In the next stage
the signal is clipped when the input signal is big enough, and in the last stage the signal is deemphasize
before it is led to the modulator in the TX EXCITER. The deemphasizing is necessary because it is a phase
modulator.

2.6.10 SQUELCH CIRCUIT

The signal from the receiver is fed to the active high pass filter U5/1-6. The filter attenuates signals below
10 KHz which means that talk will not be detected. The output of the filter is fed to the clipper Q15-6 and
the detector comprising the capacitor C45-6, the diodes D13-6, D14-6, and the resistors R3/1-6 and R5/
1-6. The rectified noise level is compared with a reference level in the voltage comparator U15/2-6. When
the noise level is higher than the reference level, the output will be low. This output is connected to PD7
on the µC, which will turn off the AF by means of U18-6, except if the squelch setting is 0 ( in the display),
The correspondence between the number in the display and the latch U4-6 can be seen below:

64 :LWKRXWFDUULHU :LWKFDUULHU

%%%% %%%%

0 1 1 1 1 1 1 1 1
1 1 1 1 0 1 1 1 1
2 1 1 0 1 1 1 1 0
3 1 1 0 0 1 1 0 1
4 1 0 1 0 1 1 0 0
5 1 0 0 0 1 0 1 0
6 0 1 1 0 1 0 0 0
7 0 1 0 0 0 1 1 0
8 0 0 1 0 0 1 0 0

PAGE 2-18

9543

2 CIRCUIT DESCRIPTION RT2047 DSC - PART II

2.6.11 AF CIRCUITS

The AF signal from the receiver is fed to the active filter U5/2-6. The filter provides a frequency response
of -6 dB/Oct. in the range 0.3 to 3 KHz and limits the signals outside this range. Further the signal is fed
to the telephone output amplifier U6/2-6 and Q6-6. From the telephone output the signal is fed through
the VOLUME CONTROL circuit U6-6 and the AL POWER AMP. The DC current in the differential amplifier
in the VOLUME CONTROL is controlled by the transistor between pins 9, 10 and 11. The attenuation will
be minimum when the current through the transistor between pins 3, 4 and 5 is maximum, and this is the
condition when the outputs B1-B4 on the latch U4-6 is high (display reading will be 15). In that case the
voltage on pin 4 of the differential amplifier will be the same as on pin 2. The D/A converter R131-6 to R134­6 is together with the resistor R128-6 functioning as a voltage divider. With all the outputs B1 - B4 at 0V
the voltage between pin 4 and pin 2 will be approx. 200 Ms. This means that the current through the
transistor between pins 3, 4 and 5 will be minimum and the signal will be attenuated about 60 dB. Resistor
R125-6 and capacitor C58-6 prevents cross talk from the supply voltage to the output of the attenuator.

The AF signal from the receiver is also led through the ‘AF from RX Buffer’ to the Handset Key Connector.
The buffer is a common emitter amplifier with emitter resistance securing a low output impedance and
the signal amplitude required for compatibility with other S.P. RADIO products. This circuit consists of
C77-6 - C79-6, Q19-6 and R157-6 - R162-6. The variable resistor R12-6 is used for adjusting gain and
does in conjunction with C78-6 and R159-6 assure a correct cutoff frequency for the amplifier.

2.6.12 SELCALL

The input to the selcall is taken from the telephone output. The signal is first amplified and limited in U3/
1-6. Then it passes the band pass filter and after this it is rectified and compared with a reference level
in the comparator U15/1-6. 2.1 MHz is divided in the programmable counter U18-6. The output of this is
divided by 2 and turned into a square wave in the flip-flop U12/1-6. The outputs of the flip-flops are
connected to the switches U13-6. The frequency at which the switches around the capacitors C29-6 and
C30-6 are working determines the resonance frequency of the filter. Thus by changing the dividing figure
to U18-6 it is possible to change the resonance frequency of the filter. With R63-6 it is possible to adjust
the resonance frequency of the filter (see the adjustment procedure).

)LJXUH I

QRPLQDO

,&LQSXW I

FORFN

I

UHV RQDQFH

QXPEHU +]  +] +]

1 1124 1010001 12963 1127
2 1197 1001100 13816 1201
3 1275 1001000 14583 1268
4 1358 1000011 15672 1363
5 1446 0111111 16667 1449

9543

6 1540 0111011 17797 1548
7 1640 0111000 18750 1630
8 1747 0110100 20192 1756
9 1860 0110001 21429 1863
0 1981 0101110 22826 1985

R 2110 0101011 24419 2123

PAGE 2-19

2 CIRCUIT DESCRIPTION RT2047 DSC - PART II
When the radio is switched on the dividing figure corresponding to the first figure in the selcall number

is put on port A on the µC which is connected to the input of U18-6. If the correct tone is received the output
of the comparator U15/1-6 goes low. This output is connected to the µC’s INT-pin. When the tone
disappears again the µC will put out the dividing figure corresponding to the next figure in the selcall
number. If all five tones are received correctly then the µC will send a message on the serial interface to
the keyboard unit, turn on the selcall relay RE2-9 (on the filter unit), and send out an alarm tone from PC1
via the volume control and power amp. to the loudspeaker. The alarm tone lasts for 10 seconds after an
individual call and after an all call it lasts until the selcall is reset. If the SELCALL TEST button is activated
the alarm circuits and indicators will be tested.

2.6.13 THE EEPROM

The EEPROM contains an address/opcode register, a data I/O register, a memory array, an internal high
voltage generator (V
and all communication starts with the µC setting PC5 thus enabling the Chip Select (CS) on the eeprom
(U8-6). Instructions to U8-6 consists of a dummy 1, a 2 bit opcode, an 8 bit address and for some
instructions also a 16 bit data word. When the opcode is 00 the 2 first bits in the address serve as an
extended opcode.

INSTRUCTION SET FOR THE EEPROM (NMC93C56):

) and some decoding logic. The Serial Data Clock (CK) is fed from PC7 on the µC

pp

,QVWUXFWLRQ 2S $GGUHVV 'DWD &RPPHQW

FRGH

READ 10 A7-A0 Reads data at specified address

EWEN 0 11XXXXXX

Write enable, must precede all

programming modes

ERASE 11 A7-A0 Erase register A7-A0

ERAL 0 10XXXXXX E rase all registers

WRITE 1 A7-A0 D15-D0 Writes reg if address unprotected

WRAL 0 01XXXXXX D15-D0

Writes all registers. Valid only when

Protect Reg is cleared

EWDS 0 00XXXXXX Disables all programming instructions

READ:

After a Read instruction is received, the instruction and address are decoded, followed by data transfer
from the selected memory register. A dummy 0 precedes the 16-bit data output string. Output data
changes are initiated by a low to high trasition of the SK clock.

WRITE:

The Write operation is followed by 16 bits of data to be written to the specified address. CS must then be
brought low before the next rising edge of the SK clock to initiate the self-timed programming cycle. D0
indicates the ready state ( 1/0 => ready/busy ) the chip is ready for another instruction.

PAGE 2-20

9543

2 CIRCUIT DESCRIPTION RT2047 DSC - PART II

2.6.14 COMMUNICATION BETWEEN THE TWO MICROCOMPUTERS

The transmission of information between the 2 µC’s takes place on a serial bus similar to a RS232C serial
interface. Each byte consists of 8 bits of information, a start-, a stop-, and a parity bit. Odd parity is being
used and the transmission speed is 2400 Baud but only one byte will be transferred in each period of 10
mS. Transmission can only take place when the DTR (PD1) is high. The µC on the KEYBOARD UNIT
will take this line high once every 10 mS.

Transmission from U19-6 to U9-7 Transmission is allowed on the ROD line (PC4) as soon as DTR is high
independent of the level of RTS. U9-7 will keep DTR high as long as it is receiving a byte.

Transmission from U9-7 to U19-6 U9-7 will set RTS (PD6 on U19-6) to a high level at the same time
as it sets DTR high. If U19-6 has nothing to transmit it will answer by setting CUTS (PC6) to a high level
as soon as it is ready to receive. After U9-7 has received the ready signal it will start transmission on the
TXD line (PD0 on U19-6). The DTR, RTS and CTS will be kept high as long as the transmission takes
place.

2.6.15 THE KEY-FUNCTION

When the transmitter is keyed the input PD2 on the Interface µC is put to a high level by the Keyboard
µC assuming that TX is allowed, TX can be prohibited when the RT2047 is operated as a slave over the
SP VHF Bus ( Described in section 2.7.5 The SP VHF Bus ). If the radio is tuned on a simplex channel!
the AF is muted by setting the output PB4 to a high level. Then the synthesizer is moved 4.6 MHz upwards.
Then the TX-VCO is turned on by setting PB3 high and after approx. 15 mS also the TX-BUFFER on (PB1
high) and after further 60 mS the PA-REGULATOR is turned on by setting PB0 and PB5 high. If reduced
power is selected PB5 will be low. When the key is released the PA-REGULATOR is turned off first. After
approx. 15 mS the TX-BUFFER is turned off, and after further 45 mS the TX-VCO is turned off. If the set
is in a simplex channel the synthesizer is moved 4.6 MHz back again, and the AF is turned on.

2.6.16 THE MICROCOMPUTER

The µC is held in reset by a low voltage on the RESET input pin. As long as the µC is in reset it is inactive
and all ports are configured as input pins. The 10V-SENSOR secures that the capacitor C54-6 cannot
be charged before the 10V supply is higher than approx. 8V. The 5V is checked internally. When the
voltage on the reset pin is above the internal comparator level the µC starts. First all pins on PA, PB, and
PC are configured as outputs. PB4, PB6, PC2, PC4 and PC5 to high level and the rest to low level. Then
the µC reads the address range from 64 to 0F in the EEPROM U8-6. If there is an error in the range from
64 to 77 the µC will transmit an “E0” message to the display and go to test mode. If there is an error in
the address range from 78 to 0F it will always initiate with channel 16, volume level at Pos. 5 and the
squelch level at 4. If the first test is passed the µC will send information to the VOL/SQ latch (U4-6) and
the RX-synthesizer and also initiate the selcall. Then the µC supervises the KEY-input (PD2), the squelsh
detector (PD7), the selcall detector (INT pin), the RTS-input (PD6), and the battery sensor. (See the
appropriate sections).

9543

PAGE 2-21

2 CIRCUIT DESCRIPTION RT2047 DSC - PART II

COMPONENT LOCATION INTERFACE UNIT MODULE 6/600

View from component side with upper side tracks. View from component side with lower side tracks.

27746D

PAGE 2-22

9543

2 CIRCUIT DESCRIPTION RT2047 DSC - PART II

DIAGRAM INTERFACE UNIT MODULE 6/600

This diagram is valid for PCB rev. 27746D.

9543

PAGE 2-23

2 CIRCUIT DESCRIPTION RT2047 DSC - PART II

2.7 KEYBOARD UNIT MODULE 7/700

2.7.1 DISPLAY

The LCD-display is static driven with an 50 Hz AC signal measured with reference to the back plane input
(BP pin numbers 1, 27, 28, 54). A segment that is off always has the same voltage as the BP. The latches
(U1-7 - U6-7) is loaded serially from the µC. Every 10 mS a strobe pulse is sent to the latches, and the
content of the internal shift register in the latches is loaded into the output latches. Afterwards new
information is shifted into the shift registers so the content is ready when the next 10 msec cycle has
passed.

2.7.2 KEYBOARD

The keyboard is scanned once every 10 mS. First PA4 is turned low, and PAO- PA3 are turned into inputs.
Afterwards PCO-PC3 are read, and if there is a low level on one of these pins a push button is activated.
If they are all high PA3 is turned low and the others to input pins, and PCO-PC3 are read once more and
so on. When finished PAO is left at low level.

2.7.3 PANEL ILLUMINATION

The LEDs are driven with a constant current generator. With PB1 at OV the current generators are on
and with PB1 at 5V they are switched off.

2.7.4 THE MICROCOMPUTER

The µC uses the internal clock-generator and a ceramic resonator. The clock frequency is approx. 4 MHz.
The µC takes care of the dual watch and scanning functions and the keyboard and display. This means
that when scanning, the µC requests a new channel every 100 mS if it has not received a message telling
that there is a carrier. Concerning the serial interface see section 2.6.14 COMMUNICATION BETWEEN
THE TWO µC’S. When the radio is on and the ON/OFF switch is activated and released again the µC will
be interrupted. The µC will then transmit a message to U19-6 to tell it to switch off. C18-7 and R17-7 is
an external pullup of the RESET*-pin and keeps the RESET* set for 0.5 second after the set is turned off
allowing time for transferring the startup table to the Interface µC. The interface µC then stores this
information in the eeprom before the set is finally turned off.

2.7.5 THE SP VHF-BUS

The keyboard µC also handles the communication with external units on the SP VHF Bus. The structure
is a digital Command/Response time division multi-pleasing data bus, with an interrupt extension. The
interrupt signal is located on pin 23 (PC5) on the µC and the serial I/O signals on pin 29/30 (PD0/PD1).
The RT2047 will always behave as a slave in the communication but can initiate a dialogue with the
external unit by setting the interrupt pin. A communication sequence will typically be initiated by the
external unit ( the master ) with an Address Word specifying what slave it wants to contact, a Command
Code or a Transfer Code ordering the slave to execute a command or to transfer information to the master
and finally a number of Data Words. The number of data Words can vary from 0 to 10. The answer from
the slave (RT2047) could consists of a Status Word, specifying what slave the answer came from and
a Response Word confirming that the command has been executed, optionally a Message Code and a
number of Data Words corresponding to the data transfer requested by the master. The answer from the
slave could also consist of a Status Word with its Busy-bit set and a Response Word confirming that the
command was received. In this case the slave will set the interrupt pin when it’s ready and the following
communication will confirm that the command was executed or optionally give the data transfer
requested. There are several other types of communication. For these and for specifics we refer to the
documentation on the SP VHF-BUS.

PAGE 2-24

9543

2 CIRCUIT DESCRIPTION RT2047 DSC - PART II
Q5-7, R18-7 and R19-7 is the Interrupt driver circuit and U10/2-7, Q4-7, C17-7, R14-7 - 16-7 and R22/

1-7 - R22/4-7 forms the serial interface circuit. This circuit transforms the µC’s two-wire serial
communication interface (SCI) into the one-wire SCI required for communication with external units. Data
output from the µC can be detected on pin PD1 and data input on pin PD0. The one-wire asynchronized
signal can be measured on R15-7 or P1/15-7.

2.7.6 DUAL WATCH

When the radio is dual-watching the receiver is watching CH16 for 100 mS once every 1.5 sec. If there
is a carrier on CH16 the receiver will stay there until the carrier disappears. When there is no carrier on
CH16 only the number of the primary channel is shown in the display along with the DW-symbol. The µC
on the keyboard is taking care of the timing and is requesting every change of channel.

2.7.7 SCANNING

When the radio is scanning the radio is listening to the channels in the scanning table for 100 mS each.
CH16 is being watched for 100 mS between every change of channel. If there is a carrier the receiver will
start dual watching on this channel as long as the SCAN TIME is set. There is built in hold time of 1.5
second so the receiver will stay there for 1.5 see after the carrier has disappeared.

9543

PAGE 2-25

2 CIRCUIT DESCRIPTION RT2047 DSC - PART II

COMPONENT LOCATION KEYBOARD UNIT MODULE 7/700

View from component side with upper side tracks.

View from component side with lower side tracks.

27747C

PAGE 2-26

9543

2 CIRCUIT DESCRIPTION RT2047 DSC - PART II

DIAGRAM KEYBOARD UNIT MODULE 7/700

This diagram is valid for PCB rev. 27747C.

9543

PAGE 2-27

2 CIRCUIT DESCRIPTION RT2047 DSC - PART II

75$160,77(5 G% 5$1*(0+]

Band-stop attenuation -30 151.425 - 152.825
Band-stop attenuation -47 156.025 - 157.425

Insertion loss. Max 1.6 -

Return loss. Mid 1.7 -

5(&(,9(5 G% 5$1*(0+]

Band-stop attenuation -60 160.625 - 162.025

Insertion loss. Max 1.5 -

Insert. loss.
max. 1.6dB

Insert. loss.
max. 1.5dB

Rx-sectionTx-section

Frequency

(MHz)

dB

-30dB

-47dB

-60dB

24902

A B

C

D E F

G

AB

C

E

D

F

G

151.425

151.825

157.425

156.025 160.625 162.025

2.8 DUPLEX FILTER MODULE 800

With a duplex filter, DF801, placed in the station it is possible to operate in full duplex mode with only one
antenna installed.

The duplex filter consists of 7 cavities, three in the Rx-section and four in the Tx-section.
The cavities in the Tx-section are stagger tuned. Two cavities (D-E) are suppressing the noise in the

receiving band 160.625 MHz - 162.025 MHz with Minimal insertion loss in the transmission band.
The function of the other two cavities (F-G) is to provide a band stop filter within the image frequency band

range of the duplex distance, 4.6 MHz: 151.425 MHz -152.825 MHz.
The cavities (A-B-C) in the Rx-section are stagger tuned. They are suppressing the transmitting

frequencies with Mid. insertion loss in the receiving band.
See the plot of duplex filters frequency response below.
NB: The duplex filter is adjusted with special measuring equipment and should be adjusted by S.P. Radio

A/S only.

TECHNICAL DATA FOR DUPLEX FILTER FOR VHF RT146 - RT2047.

PAGE 2-28

9543

2 CIRCUIT DESCRIPTION RT2047 DSC - PART II

2.9 FILTER UNIT MODULE 9/900

The function of the Filter unit is to protect the set against RF interference from equipment installed near
the set. The two options AUX II and SELCALL RELAY requires the relays RE1-9 and RE2-9. These relays
are not a standard feature and can, if needed, be acquired from SP-Radio ( order number 21.300 ).

The function of jumper P34-9 is described in part I, section 2.9 Special Options.

9543

PAGE 2-29

2 CIRCUIT DESCRIPTION RT2047 DSC - PART II

COMPONENT LOCATION FILTER UNIT MODULE 9/900

View from component side with upper side tracks.

View from component side with lower side tracks.

27749C

PAGE 2-30

9543

2 CIRCUIT DESCRIPTION RT2047 DSC - PART II

DIAGRAM FILTER UNIT MODULE 9/900

This diagram is valid for PCB rev. 27749C.

9543

PAGE 2-31

9546

2 CIRCUIT DESCRIPTION RT2047 DSC - PART II

32162

9546

PAGE 2-33

2 CIRCUIT DESCRIPTION RT2047 DSC - PART II

5

9

1

6

7

3

5

2

4

1

6

MC801

MIC PRE-AMP

WHITE

P803
DIN
CONNECTOR

BLUE

TC801

RED
YELLOW

BROWN

HAND KEY

S801

VHF RT2047 SCRAMBLER CRY2001, RE2100, RT2047 prepared for DSC and RT2048

S1

HAND KEY

YELLOW

RED

TC1

MIC PRE-AMP

MC1

D-CONNECTOR

BLUE

WHITE

BROWN

SHORTWAVE S130X

S1701

HAND KEY

BROWN

WHITE

RED

TC1701

BLUE

CONNECTOR

HIRSCHMANN

P1701

YELLOW

MIC PRE-AMP

MC1701

6

1

4

2

5

3

MC1

R1

1k8

C1

100u

10nC2D1

1N4148

8k2

R3

R5

2k7

2k2

R7

R9
2k7

R10

120k

R2
1k8

*

C3

10u

u47

C4

R4

18k

MIC. PRE-AMPLIFIER (100)

33u

C10

39k

R11

4k7

R6

C5

2u2

2u2

C6

R8

6k8

C9

1n

10u

C7

1n

C8

C11

10n

390 +10-18v

For TEST

4-0-24025E

In orange marked microtelephone cartridge, R2 is changed from 1k8 to 5k6 ohm.

10mV/DIV

OV

0.5msec/DIV 0.5msec/DIV

OV

10mV/DIV

T3

BC547C

BC547C

T2

BC547C

T1

27777A

C12

27pf

C13

27pf

C14

15pf

C14

15pf

C4 C5C10

C6

C7

T2

T3

T1

C1

C3

R3

R2

R5

R11

R1

R7

R10

R9

D1

C2

C9

R4

R6

R8

C8

C11

C13

C12

2.11 MICROTELEPHONE INSTALLATION

MICROTELEPHONE WITH ELECTRET MIC. AMP. ECI A/S 5-0-24025D 60087

POSITION DESCRIPTION MANUFACTOR TYPE PART NO.

C1 CAPACITOR ELECTROLYTIC 100uF 20% 10VDC ERO EKI 00 BB 310 C M0E 14.607
C2 CAPACITOR CERAMIC 10nF -20/+80% CL2 50VDC NKE DT 350 758L F 103 Z 50V 15.170

C3 CAPACITOR ELECTROLYTIC 10uF 20% 35VDC ERO EKI 00 AA 210 F M0E 14.512
C4 CAPACITOR ELECTROLYTIC 0.47uF 20% 50VDC ERO EKI 00 AA 047 H M0E 14.504
C5 CAPACITOR ELECTROLYTIC 2u2F 20% 50VDC ERO EKI 00 AA 122 H M0E 14.503
C6 CAPACITOR ELECTROLYTIC 2u2F 20% 50VDC ERO EKI 00 AA 122 H M0E 14.503
C7 CAPACITOR ELECTROLYTIC 10uF 20% 35VDC ERO EKI 00 AA 210 F M0E 14.512
C8 CAPACITOR CERAMIC 1nF 10% 100V *PHILIPS 2222 630 19102 16.149
C9 CAPACITOR CERAMIC 1nF 10% 100V *PHILIPS 2222 630 19102 16.149
C10 CAPACITOR ELECTROLYTIC 33uF 20% 16VDC ERO EKI 00 AA 233 D M0E 14.518
C11 CAPACITOR CERAMIC 10nF -20/+80% CL2 50VDC NKE DT 350 758L F 103 Z 50V 15.170

D1 DIODE 1N4148 HIGH SPEED PHILIPS 1N4148-143 25.131
MC1 MICROPHONE ELECTRET ø9.7 x 6.7mm PANASONIC WM-0344BY 46.012
R1 RESISTOR MF 1k8 OHM 5% 0.33W PHILIPS 2322 180 73182 02.478
R2 RESISTOR MF 1k8 OHM 5% 0.33W PHILIPS 2322 180 73182 02.478
R3 RESISTOR MF 8k2 OHM 5% 0.33W PHILIPS 2322 180 73822 02.494
R4 RESISTOR MF 18k OHM 5% 0.33W PHILIPS 2322 180 73183 02.502
R5 RESISTOR MF 2k7 OHM 5% 0.33W PHILIPS 2322 180 73272 02.482
R6 RESISTOR MF 4k7 OHM 5% 0.33W PHILIPS 2322 180 73472 02.488
R7 RESISTOR MF 2k2 OHM 5% 0.33W PHILIPS 2322 180 73222 02.480
R8 RESISTOR MF 6k8 OHM 5% 0.33W PHILIPS 2322 180 73682 02.492
R9 RESISTOR MF 2k7 OHM 5% 0.33W PHILIPS 2322 180 73272 02.482
R10 RESISTOR MF 120k OHM 5% 0.33W PHILIPS 2322 180 73124 02.522
R11 RESISTOR MF 39k OHM 5% 0.33W PHILIPS 2322 180 73393 02.510
S1 MICROSWITCH E62-10H PDT CHERRY E62-10H PDT 44.025
T1 TRANSISTOR AF NPN BC547C TO-92 PHILIPS BC547C 28.068
T2 TRANSISTOR AF NPN BC547C TO-92 PHILIPS BC547C 28.068
T3 TRANSISTOR AF NPN BC547C TO-92 PHILIPS BC547C 28.068
TC1 TELEPHONE CARTRIDGE 200 OHMS S.E.K. (KIRK) T802 0113 2715 46.010

PAGE 2-34

FLAT PACK

FLAT PACK

9543

2 CIRCUIT DESCRIPTION RT2047 DSC - PART II

2.12 SPECIAL INSTALLATION WITH 2 MICROTELEPHONES

H2086 for scrambler CRY2001, RT2047 DSC, RT2048 and RE2100.
H2087 for VHF RT2047.

H2087

MICROTELEPHONE
CONNECTOR CONNECTOR

P1

7

6

3

1

5

2

4

J2 (H2087)

6

1

4

2

P2 (H2087)

6

1

4

2

5

5

RED

YELLOW

WHITE

BLUE

BROWN

7

3

7

3

H2086

MICROTELEPHONE

1

6

2

7

3

8

4

9

5

P1

BROWN
RED
YELLOW
WHITE

BLUE

WHITE
BLUE
WHITE
YELLOW
RED
BROWN

RED

YELLOW

WHITE

BLUE

BROWN

Hook 1

1 2

3 495

6

7 8

6

RED

YELLOW

HOOK 2/3

1 2

3 495

6

7 8

WHITE

BLUE

59438721

BROWN

BROWN

RED

YELLOW

WHITE

BLUE

J2

P2

BROWN

RED

YELLOW

WHITE

BLUE

J3

S1

S2

BLUE/GREEN
BLUE/BLACK

BLUE/GREEN
BLUE/BLACK

Connection Board (1)

5-0-24281 B

Connection Board (1)

5-0-24281 B

NORMAL MICROTELEPHONE
program 2000 (HANDSET)

RED

YELLOW

RED

YELLOW

BROWN

BLUE

WHITE

BROWN

The cable between the Hooks
is not factory delivered (7 x 0.14 mm )

RED

YELLOW

BROWN

BLUE

WHITE

MICROTELEPHONE
(HANDSET 2)

7

1 2 3 4 5 6

WHITE

BLUE

7

1 2 3 4 5 6

TC

HAND KEY 1

MIC PRE-AMP MC

2

TC

HAND KEY 2

MIC PRE-AMP MC

RED

27778

6

59438721

P3

S1. 2. 3 is shown with microtelephone in Hook.
Recommended cable lenght max. 20 meters.

YELLOW

WHITE

BLUE

BROWN

If H2087 is used and if there is "Hum" or noice problems with
the modulations, the ground wires white and yellow in P3 must
be seperated. Yellow wire on Pin 2, and white wire in P7.

9543

PAGE 2-35

2 CIRCUIT DESCRIPTION RT2047 DSC - PART II

2.13 SPECIAL INSTALLATION WITH 3 MICROTELEPHONES

H2088 for scrambler CRY2001, RT2047 DSC, RT2048 and RE2100.
H2089 for VHF RT2047.

H2089

MICROTELEPHONE
CONNECTOR CONNECTOR

P1

7

6

3

1

5

2

4

J2 (H2089)

6

1

4

2

P2 (H2089)

6

1

4

2

5

5

RED

YELLOW

WHITE

BLUE

BROWN

7

3

7

3

H2088

MICROTELEPHONE

6

7

8

9

P1

BROWN
RED
YELLOW
WHITE

BLUE

WHITE
BLUE
WHITE
YELLOW
RED
BROWN

1

2

3

4

5

RED

YELLOW

WHITE

BLUE

BROWN

Hook 1

1 2

3 495

6

7 8

6

RED

YELLOW

HOOK 2/3

6

WHITE

BLUE

59438721

BROWN

59438721

BROWN

RED

YELLOW

WHITE

BLUE

J2

P2

BROWN

RED

YELLOW

WHITE

BLUE

J3

S1

S2

BLUE/GREEN
BLUE/BLACK

BLUE/GREEN
BLUE/BLACK

Connection Board (1)

5-0-24281 B

Connection Board (1)

5-0-24281 B

NORMAL MICROTELEPHONE
program 2000 (HANDSET)

RED

YELLOW

RED

RED

YELLOW

YELLOW

BROWN

BLUE

WHITE

BROWN

The cable between the Hooks
is not factory delivered (7 x 0.14 mm )

RED

YELLOW

BROWN

BLUE

WHITE

BROWN

MICROTELEPHONE
(HANDSET 2)

7

1 2 3 4 5 6

WHITE

BLUE

7
654321

BLUE

WHITE

TC

HAND KEY 1

MIC PRE-AMP MC

2

TC

HAND KEY 2

MCMIC PRE-AMP

1 2

3 495

6

7 8

RED

YELLOW

HOOK 2/3

1 2

6

7 8

6

BLUE

WHITE

3 495

BROWN

59438721

P3

BROWN

RED

YELLOW

WHITE

BLUE

J4

P4

S3

BLUE/GREEN
BLUE/BLACK

Connection Board (1)

5-0-24281 B

S1. 2. 3 is shown with microtelephone in Hook.

MICROTELEPHONE
(HANDSET 3)

RED

7

1 2 3 4 5 6

YELLOW

BROWN

BLUE

WHITE

TC

HAND KEY 3

MIC PRE-AMP MC

Recommended cable lenght max. 20 meters.

RED

YELLOW

WHITE

BLUE

BROWN

27779

If H2089 is used and if there is "Hum" or noice problems with
the modulations, the ground wires white and yellow in P3 must
be seperated. Yellow wire on Pin 2, and white wire in P7.

PAGE 2-36

9543

2 CIRCUIT DESCRIPTION RT2047 DSC - PART II

2.14 MECHANICAL DIMENSIONS FOR HANDSET

MECHANICAL DIMENSIONS FOR HANDSET

81

64

80

436543

ø4.5

151

275

27946

MECHANICAL DIMENSIONS FOR HANDSET HOLDER WITH MICROSWITCH

103

64

ø4.5

80

32 32

80

436543

ø4.5

9543

151

26999

275

ø4.5

80

32 32

PAGE 2-37

2 CIRCUIT DESCRIPTION RT2047 DSC - PART II

MECHANICAL DIMENSIONS FOR HANDSET

78

62

ø4.5

132

275

4-0-29938

MECHANICAL DIMENSIONS FOR HANDSET HOLDER WITH MICROSWITCH

103

64

65 8080

ø4.5

32 32

8080

43

ø4.5

151

4-0-29937

PAGE 2-38

275

6543

ø4.5

32 32

9543

2 CIRCUIT DESCRIPTION RT2047 DSC - PART II

2.15 DC POWER SUPPLY N418

GENERAL DESCRIPTION

The power supply N418 is constructed for supplying a 13.2V VHF from a 24V DC system. In order to obtain
high efficiency regulation is obtained by the switch mode principle.

TECHNICAL DATA:

The power supply N418 is controlled from the connected VHF unit by on/off.

Input voltage 16- 32V DC
Output voltage 13.2V DC
Output current Max. 7A DC
Operation temperatur e range -15 - +55 °C
Switch fr equency Appr ox 40 KHz

2.15.1 PRINCIPLE OF OPERATION

The on/off information from the connected VHF unit is controlling the N418 via pin 4 of P201.
The regulation takes place after the forward principle, which means that during the “on time” of the
switching element T202, the coil L105 is connected directly from the input to the output.

When switching element T202 is turned off the stored energy in L105 maintains the supply current to the
output via diode D201.

Regulation of the output voltage takes place via pulse width regulation, which means that the “on time”
(duty cycle) of the switching element T202 is controlled. The regulation gives long “on time” when the input
voltage is low, a further decrease of input voltage allows the T202 to be on, continuously. If the input
voltage is increased the “on time” is shortened.

In order to limit the rush in current during switching there’s a built in soft start, thus enabling a short “on
time” for T202 immediately after the switching on, and afterwards the “on time” is slowly increased.
Current limitation is established by sensing the voltage over the resistor R126. If the current is too high,
the pulse width is shortened in order to reduce the output current.

2.15.2 CIRCUIT DESCRIPTION

When N418 is switched on R113 is connected to the negative terminal of the supply in the VHF and
transistor T102 is on. IC101 starts functioning. The voltage level on pin 9 of IC101 controls the duty cycle
and the voltage always starts from low level because C108 is discharged via transistor T101 every time
the N418 is switched off.

Pin 16 of IC101 is a 5V reference voltage, which is divided down in R104, R105, and R106 and connected
to pin 2 (the non-inverted input). Pin 1 of IC101 is connected to the output voltage via voltage divider R117
and R122, the two levels are compared and the pulse width is controlled so that the output voltage stays
stable. Pin 11 and 14 are outputs connected in parallel, the signal forms the drive signal for the switching
element T202 via T103 and T201 . The components L103, L104, R123, R124, R125, and C121 control
the on and off switching of T202 and D201. D105 prevents inverse polarity across T202.

The IC102 senses the output current via the voltage over R126. If this voltage is too high - due to an
overload - the pulse width and thus the output voltage is reduced.
The capacitors and coils in input and output suppresses switching noise enabling N418 to fulfill the CISPR
noice regulations.

9543

PAGE 2-39

2 CIRCUIT DESCRIPTION RT2047 DSC - PART II

2.15.3 ADJUSTMENT PROCEDURE

ADJUSTMENT OF OUTPUT VOLTAGE.

Measure the output voltage across C126 with a load equal to the consumption of a VHF unit in receive
condition (0.5 - 0.8A). Adjust R105 until the output is 13.2V if necessary.

ADJUSTMENT OF MAX. CURRENT.

Check that the output voltage is still 13.2V with a load of 5.8A (2.3 ohm) across the output.
Change the load to 1,5 ohm by connecting 4.3 ohm in parallel with the 2.3 ohm. The voltage will then be

10.5V and the output 7A. If necessary adjust the output to 10.5V with R111.

COMPONENT LOCATION DC POWER SUPPLY N418

View from component side with lower side tracks.

23818C

PAGE 2-40

9543

2 CIRCUIT DESCRIPTION RT2047 DSC - PART II

DIAGRAM DC POWER SUPPLY N418

This diagram is valid for PCB rev. 23818C.

PAGE 2-41

9543

2 CIRCUIT DESCRIPTION RT2047 DSC - PART II

,QSXW9ROWDJH

21.6 to 31.2V DC

2XWSXW9ROWDJH

13.4V DC

2XWSXW&XUUHQW Max. 8A DC

2SHUDWLRQ7HPSHUDWXUH5DQJH 15°C to +55°C

)XVH 8 Amp. 5 x 20 mm

&XUUHQWIURPRQRII7HUPLQDO Less than 15 mA DC

2.16 N420 24V/12V REGULATOR

GENERAL DESCRIPTION

The regulator N420 is a general purpose 24V DC to 13.2V DC regulator, e.g. to be used for supply of VHF
radiotelephones.

The regulator N420 is a serial regulator with excellent noise performance.

2.16.1 TECHNICAL DATA

The regulator N420 is controlled from the connected VHF unit by the on/off button.

2.16.2 PRINCIPLE OF OPERATION

N420 is a linear serial regulator where most of the loss is dissipated in resistors. It is provided with a
terminal for remote shut-down. If the on/off terminal is connected to the -terminal, the regulator is on. If
the on/off terminal is disconnected, the regulator is off.

2.16.3 CIRCUIT DESCRIPTION

The output voltage is regulated by the integrated voltage regulator IC1. The output voltage is 12V DC plus
the forward voltage over diodes D5 and D6: approx. 13.4V DC in total if T4 is conducting. If the output
voltage drops the current through IC1 and R5 increases. An increase in voltage across R5 will result in
an increase in current in T1 and the resistors R10 - R23 resulting in an increase in the output current.
T1 delivers most of the output current and FC1 only a small driver current.

If the input voltage is low and the output current is high, the voltage across R10 -R23 results in T1 going
into saturation. The voltage across R4 increases and when the voltage across R4 and VBE Of T1 is greater
than approx. 1 Volt, T3 starts to conduct base current to T1. This transistor then shunts the remaining
current to the output, bypassing R10 - R23.
When the input voltage and the output current are high, T1 is nearly saturated. When the input voltage
is low and the output current is high, the resistors R1 - R3 will result in saturation of both T1 and T2. The
combination of T1 in saturation and T2 delivering the remaining output current divides the total loss, so
the main loss is in the resistors giving low loss in the semi-conductors and a lower junction temperature,
resulting in a higher reliability for the whole regulator.
T4 is used to switch the regulator ON and OFF. If the ON/OFF input is disconnected T4 is OFF and the
base currents to T1 and T2 are zero and the current through IC1 will also be reduced to zero. The stand­by current consumption is then less than 10 micro amp. If the ON/OFF input is connected to - input, T4
goes into saturation and the regulator starts.

PAGE 2-42

9543

2 CIRCUIT DESCRIPTION RT2047 DSC - PART II
In case of a short-circuit over the output R5 and D3 limits the current through IC1 and T4 to approx. 250

mA and R1 - R3 and D3 limits the current through T1 and T2 to approx. 15 Amp. The temperature of the
cooling surface will increase and activate the thermal protection circuit inside IC1 and lower the output
voltage, even though a short-circuit of the output should be avoided.

The diode D1 protects against reverse input voltage. A fuse will blow in case of reverse input.

9543

PAGE 2-43

2 CIRCUIT DESCRIPTION RT2047 DSC - PART II

COMPONENT LOCATION 24V/12V REGULATOR N420

View from component side with upper side tracks. View from component side with lower side tracks.

24613F

PAGE 2-44

9543

2 CIRCUIT DESCRIPTION RT2047 DSC - PART II

DIAGRAM 24V/12V REGULATOR N420

This diagram is valid for PCB rev. 24613F.

9543

PAGE 2-45

2 CIRCUIT DESCRIPTION RT2047 DSC - PART II

DIMENSION AND DRILLING PLAN N420

PARTS LISTS N420

VOLTAGE REGULATOR N420 ECI A/S 5-0-24613G 600416

POSITION DESCRIPTION MANUFACTOR TYPE PART No.

C1 CAPACITOR ELECTROLYTIC 47uF -10/+50% 63V ERO EB 00 FL 247 J 14.552
C2 CAPACITOR MKT 0.22uF 10% 63V ERO* MKT1818 11.090
C3 CAPACITOR MKT 0.22uF 10% 63V ERO* MKT1818 11.090
C4 CAPACITOR ELECTROLYTIC 47uF -10/+50% 63V ERO EB 00 FL 247 J 14.552
C5 CAPACITOR MKT 100nF 10% 100VDC PHILIPS 2222 371 28104 11.180
D1 DIODE MR750 MOTOROLA MR750 25.219
D2 DIODE SCHOTTKY BAT 43 THOMSON-CSF BAT43 27.600
D3 DIODE ZENER 7.5V 5% 0.4W BZX79C7V5 PHILIPS BZX79C7V5 26.539
D5 DIODE 1N4148 HIGH SPEED PHILIPS 1N4148-143 25.131
D6 DIODE 1N4148 HIGH SPEED PHILIPS 1N4148-143 25.131
F1 FUSE 8AF 250V Ø5x20mm ELU 171 100 8AF 45.561

(DIN 41571/1)
IC1 VOLTAGE REGULATOR +12V MOTOROLA* MC7812CT 31.260
R1 RESISTOR POWER 1R0 OHM 10% 6.5W VITROHM 1R0 10% TYPE 296-0 05.725
R2 RESISTOR POWER 1R0 OHM 10% 6.5W VITROHM 1R0 10% TYPE 296-0 05.725
R3 RESISTOR POWER 1R0 OHM 10% 6.5W VITROHM 1R0 10% TYPE 296-0 05.725
R4 RESISTOR 47 OHM 5% 0.6W BEYSCHLAG MBB 0207-00-BX-47R 5% 03.167
R5 RESISTOR PMF 27 OHM 5% 3W PHILIPS 2322 195 13279 04.660
R6 RESISTOR MF 1k0 OHM 5% 0.4W PHILIPS 2322 181 53102 01.200
R7 RESISTOR MF 1k0 OHM 5% 0.4W PHILIPS 2322 181 53102 01.200
R8 RESISTOR MF 10k OHM 5% 0.4W PHILIPS 2322 181 53103 01.225
R9 RESISTOR 2.2 KOHM 5% 0.6W DRALORIC SMA 0207 S TK100-2K2 5% 03.208
R10 RESISTOR POWER 6R8 OHM 10% 6.5W VITROHM 6R8 10% TYPE 296-0 05.730
R11 RESISTOR POWER 6R8 OHM 10% 6.5W VITROHM 6R8 10% TYPE 296-0 05.730
R12 RESISTOR POWER 6R8 OHM 10% 6.5W VITROHM 6R8 10% TYPE 296-0 05.730
R13 RESISTOR POWER 6R8 OHM 10% 6.5W VITROHM 6R8 10% TYPE 296-0 05.730
R14 RESISTOR POWER 6R8 OHM 10% 6.5W VITROHM 6R8 10% TYPE 296-0 05.730
R15 RESISTOR POWER 6R8 OHM 10% 6.5W VITROHM 6R8 10% TYPE 296-0 05.730
R16 RESISTOR POWER 6R8 OHM 10% 6.5W VITROHM 6R8 10% TYPE 296-0 05.730
R17 RESISTOR POWER 6R8 OHM 10% 6.5W VITROHM 6R8 10% TYPE 296-0 05.730
R18 RESISTOR POWER 6R8 OHM 10% 6.5W VITROHM 6R8 10% TYPE 296-0 05.730
R19 RESISTOR POWER 6R8 OHM 10% 6.5W VITROHM 6R8 10% TYPE 296-0 05.730
R20 RESISTOR POWER 6R8 OHM 10% 6.5W VITROHM 6R8 10% TYPE 296-0 05.730
R21 RESISTOR POWER 6R8 OHM 10% 6.5W VITROHM 6R8 10% TYPE 296-0 05.730
R22 RESISTOR POWER 6R8 OHM 10% 6.5W VITROHM 6R8 10% TYPE 296-0 05.730
R23 RESISTOR POWER 6R8 OHM 10% 6.5W VITROHM 6R8 10% TYPE 296-0 05.730
T1 TRANSISTOR DARLINGTON MJ2501 TEXAS* MJ2501 29.235
T2 TRANSISTOR DARLINGTON MJ2501 TEXAS* MJ2501 29.235
T3 TRANSISTOR AF BC547B NPN TO-92 PHILIPS BC547B 28.067
T4 TRANSISTOR BD140-10 AEG* BD140-10 29.066

25332

N420 must only be mounted vertically.
Free distance must be kept to allow circulation.

PAGE 2-46

9543

RT2047 DSC - PART II

CONTENTS

3 MECHANICAL DISASSEMBLING AND MODULE LOCATION 3-1

3.1 MECHANICAL DISASSEMBLING 3-1

3.2 MODULE LOCATION 3-3

9546

RT2047 DSC - PART II

3 MECHANICAL DISASSEMBLING AND MODULE LOCATION

3.1 MECHANICAL DISASSEMBLING

9545

PAGE 3-1

3 MECHANICAL DISASSEMBLING AND MODULE LOCATION RT2047 DSC - PART II

PAGE 3-2

9545

3 MECHANICAL DISASSEMBLING AND MODULE LOCATION RT2047 DSC - PART II

3.2 MODULE LOCATION

MICROTELEPHONE

ANTENNA

CONNECTOR J803

CONNECTOR J801

POWER

CONNECTOR P802

FILTER UNIT (9/900)

RX-SYNTHESIZER (200)

U2
Q9
U1

Q11

R68
R65
R29

Q1

VDRX (R6)

R16
R13
R23
R61

F1
RE3
P3/PIN9
R82
R74
R162
R63
INTERFACE UNIT

(6/600)

DUPLEX FILTER
DF801

501295

FLO1 TO RX

RECEIVER UNIT (100)

L202

L108

L206

L106

R209

FLO1 TO TX

L105

VVCO (R217)

L104

L103

L102

L101

LOUDSPEAKER

LS801

501293

KEYBOARD UNIT
(7/700)

TX-POWER AMP

(400)

C419
C413
C423
C331
T306

FP301

DUPLEX FILTER
DF801

C408
ANTENNA RELAY

(500)
C407
TX-EXCITER (300)
L307
R341
R344
L306
R332 TX TO

PA OUTPUT

9545

501530

RECEIVER

(100)

LOUDSPEAKER

LS801

KEYBOARD UNIT
(7/700)

LOUDSPEAKER

LS801

501294

KEYBOARD UNIT
(7/700)

PAGE 3-3

501292

RT2047 DSC - PART II

CONTENTS

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

9546

4 SERVICE RT2047 DSC - PART II

4 SERVICE

4.1 MAINTENANCE

PREVENTIVE MAINTENANCE

If RT2047 has been installed properly the maintenance can be reduced to an overhaul at each visit of our
service staff. Inspect the set, the antenna, cables and plugs for mechanical damages, salt deposits,
corrosion and any foreign materials. Due to its solid structure the RT2047 has a long lifetime, but due to
the operating conditions it should be carefully controlled at maximum 12 month intervals. The set should
be taken to a certified service point for testing. Along with each set a “Test-sheet” is delivered in which
all the measurements made in the test department of the factory are listed. If the control measurements
made in the service workshop should show other values then those listed in the “Test-sheet”, the set must
be adjusted as specified under Adjustment Procedure.

4.2 ADJUSTMENT INSTRUCTIONS

INTRODUCTIONS

The measuring values indicated in paragraph 2 concerning circuit description and schematic diagrams
are typical values and it will be necessary to use instruments in absolute conformity with the list below:

4.3 PROPOSAL FOR NECESSARY MEASURING INSTRUMENTS

VHF Signal Generator type TF2015 MARCONI
FM Modulation Meter type TF2303 MARCONI
Distortion Analyzer type TF2337A MARCONI
AF Volmeter type VT-121 TRIO
Tone Generator type PM5107 PHILIPS
Electronic Multi meter type PM2505 PHILIPS
RF Directional Watt meter Model 43 BIRD
50W Load with 30 dB Attenuator type 8321 BIRD

FREQUENCY COUNTER:
Frequency range
Sensitivity
Impedance
Accuracy

We also recommend the portable universal VHF test set from Radio Holland,
the Omnitester type RH-4316 . This test set is designed especially for fast and accurate service of VHF
transceivers.

> 175 MHz
< 100 mV
> 1 MW & 50W
< 1×10

-6

9545

PAGE 4-1

4 SERVICE RT2047 DSC - PART II

TEST PROBE

RF

1nF

ceramic

AA119

AA119

1nF
ceramic

LAYOUT OF THE PROBE

10.00 12.00 70.00

Metal tube

Insulating material

25079

To multimeter

ø10

4.4 CALIBRATION OF THE TEST PROBE

For some test probe measurements it is necessary to use a test probe calibrated with a specified multi
meter.

NECESSARY EQUIPMENT FOR THIS PROCEDURE:

1. Diagram for the measurements

2. Test probe

3. Multi meter

4. New factory adjusted RT2047

4.5 PROCEDURE FOR CALIBRATION

1. Switch on the set.

2. Select channel 28.

3. Remove coax cable from the soldering point for F
it with a 50 resistor.

4. Connect the test probe to the point mentioned above and record the result in the diagram.

5. Remove the resistor and solder back the coax cable.

6. Follow the procedure mentioned above by measuring the levels from F
Synthesizer and the TX drive level from the TX-Exciter.

All other test probe measurements are relative and ought to be measured with the same test probe and
recorded in the diagram.

to RX on the RX-Synthesizer and replace

L01

to TX on the RX-

L01

PAGE 4-2

9545

4 SERVICE RT2047 DSC - PART II

4.6 ADJUSTMENT PROCEDURE

4.6.1 ADJUSTMENTS OF INTERFACE UNIT MODULE 6/600

ADJUSTMENT AND CONTROL OF VOLTAGE REGULATORS.

1. Switch on the set.

2. Select channel 28.

3. Check 13.2V with a multi-meter on fuse F1-6 and P3-6 pin 9.

4. Check 5V +0.2V with a multi-meter on U1-6 pin 3.

5. Connect the multi-meter to Q9-6’s collector and adjust the 10V regulator with R65-6 to 10V +0.2V.

6. Connect the multi-meter to Q11-6’s collector and key the transmitter.

7. Adjust the PA-regulator with R68-6 to 8.4V

+ 0.2V.

8. Connect the multi-meter to R6-6.

9. Adjust RX-control voltage (VD

) to 8V + 0.2V with R16-6.

RX

ADJUSTMENT OF SELCALL TEST TONE

The procedure is described in the manual, INSTRUCTIONS FOR IDENTITY AND
SERVICE PROGRAMMING OF VHF RT2047, section 3.8: SELCALL TEST TONE

4.6.2 ADJUSTMENTS OF RX-SYNTHESIZER MODULE 200

1. Select channel 28.

2. Check the DC-control voltage on R217 with a multi meter to be 8V

+ 0.4V. If components have been
changed in the VCO-circuit, it is possible that the jump wire used for adjusting the VCO frequency
range has to be moved until the 8

3. Control the frequency F

ADJUSTMENT OF F

TO TX AND F

L01

to RX with a frequency counter to be 140.600 MHz.

L01

1. Connect “calibrated” test probe to soldering point for F

+ 0.4 V is achieved.

TO RX.

L01

to TX.

L01

2. Adjust L202 until the core is 0.5 mm over the coil form and potentiometer R209 CCW to 1/3 of the
range.

3. Adjust L206 to Max. deflection on the Tp meter.

4. Select channel 6.

5. Check the deflection on the Tp meter to be nearly the same as ch. 28. Otherwise obtain the level
on ch. 6 and ch. 28 to be nearly the same by adjusting L206.

6. Connect test probe to soldering point for F

to RX.

L01

7. Adjust L202 to Max. deflection on the Tp meter and secure that deflection on ch. 6 and ch. 28 are
nearly the same.

The levels measured with power meter (mW) and 50 W impedance must be:

F

to TX: 0.25 mW

L01

to RX: 5 mW +1.5 dB.

F

L01

4.6.3 ADJUSTMENTS OF TX-EXCITER MODULE 300

1. Select channel 28.

2. Connect frequency counter to the top of T306.

3. Adjust trimming capacitor C331 until the frequency counter shows 21MHz
the transmitter is keyed you can measure on R332 and adjust R331 until the frequency counter
show 157400000 Hz + 150 hz.

4. Check the clock frequency on microprocessor to be 2.1 MHz on FP301 .

5. Check the DC-control voltage on R344 to be 8

+ 0.4V. If components have been changed in the
VCO-circuit it is possible that the jump wire used for adjusting the VCO frequency range has to be
moved until the 8

9545

+ 0.4V is achieved. (With the Transmitter Keyed)

+ 20Hz. Note that when

PAGE 4-3

4 SERVICE RT2047 DSC - PART II

ADJUSTMENT OF TX-DRIVE LEVEL.

1. Remove coax cable from TX-PA and solder a 50 W resistor from TX to PA output to ground.

2. Connect test probe to TX to PA output.

3. Adjust coils L306 and L307 to Max deflection on the Tp meter and ensure that the levels on ch. 6
and ch. 28 are nearly the same.

4. Adjust R341 to the correct output: about 3.8V on the Tp meter.

5. Remove the 50 W resistor and solder the coax cable back to the output point.

4.6.4 ADJUSTMENTS OF TX-POWER AMPLIFIER MODULE 400

ADJUSTMENT OF OUTPUT POWER.

1. Select channel 20.

2. Connect RF-power meter and a 50 W/ 25 Watt load resistor to the antenna connector J801.

3. Adjust trimming capacitors C423, C419, C413, C408, C407 to Max. deflection on the power meter.

4. Repeat the adjustment under part 3 several times to get Max. output power.

5. Adjust R68-6 on interface unit until the power meter shows 25 Watt. Max PA regulator Vcc = 10.5V.

6. Set output power to 1W.

7. Adjust R29-6 on the interface unit until the power meter shows 0.8 Watt.

4.6.5 ADJUSTMENT OF MODULATION ON INTERFACE UNIT MODULE 6/600

1. Select channel 28.

2. Disconnect the blue wire on the Filter Unit coming from J3-8 pin 3.

3. Connect tone generator and AF Volmeter between the solder terminal for the disconnected blue
wire and ground (the white wire next to it).

4. Set power output level to 1W.

5. Connect modulation meter loosely to the RF-load resistor.

6. Connect distortion analyzer to the modulation meter.

7. Turn potentiometer R61 to the middle of its adjustment range.

8. Set the tone generator to a frequency of 1000 Hz and the output level to 1 V
mV

+ 20 dB). Read the level on the AF-volmeter.

RMS

(nominal level 100

RMS

9. Key the transmitter.

10. Adjust R23-6 to Max. deviation: D F =

11. Set level of tone generator to nominal level: 100 mV

12. Adjust R61-6 to nominal modulation: D F =

+ 5.0 kHz.

+ 3.0 kHz.

RMS

.

13. Check that the distortion is less than 5%.

4.6.6 ADJUSTMENT OF RECEIVER UNIT MODULE 100

ADJUSTMENT OF RF AND IF AMPLIFIER

1. Select channel 28.

2. Connect the signal generator to the antenna connector J801.

3. Connect the test probe to pin 16 on U101.

4. Set the signal generator frequency to 162.000 MHz and increase the level until the deflection on

meter reaches 30% of maximum deflection.

the T

5. Readjust the signal generator level during the adjustment, if necessary to keep the same deflection

6. Adjust coils L101, L102, L103, L104, L105, L106 to maximum deflection on the T

7. Select channel 6.

8. Set signal generator to 156.300 MHz.

9. Adjust potentiometer R16-6 (interface unit) to maximum deflection on the Tp meter.

10. Select channel 28.

11. Set the signal generator frequency to 162.000 MHz.

12. Adjust coils L101, L102, L103, L104 to maximum deflection on the Tp meter.

p

on the T

meter. You must be sure that the signal is not compressed.

p

meter.

p

PAGE 4-4

9545

4 SERVICE RT2047 DSC - PART II

ADJUSTMENT OF DETECTOR, TELEPHONE-AMPLIFIER, LF-POWER-AMPLIFIER AND THE AF
FROM RX BUFFER

1. Select channel 6.

2. Connect the signal generator to the antenna connector J801.

3. Connect frequency counter between pin 3 of U101 and frame through a 10 uF capacitor.

4. Set signal generator level to -30 dBm (no modulation)

5. Adjust signal generator frequency until frequency counter shows 455.0 kHz ± 100 Hz.

6. Set modulation on signal generator to nominal modulation, fm = 1kHz and frequency deviation D
f = ± 3 kHz.

7. Connect the AF voltmeter to the telephone output, pin 1 on J803 or the solder terminal on the Filter­Unit for the red/orange wire. (The telephone output must be loaded with 200 W or a telephone).

8. Adjust coil L108 to maximum deflection on the AF voltmeter.

9. Adjust potentiometer R74-6 to an AF level of 0.45 V

RMS

.

10. Connect a distortion analyzer between the orange and green wire (ground) on the Filter-Unit.

11. Set volume control to maximum level (Pos. 15).

12. Adjust potentiometer R113-6 to 3.3 V

over 4 W.

RMS

13. Check that distortion is below 5%.

14. Connect AF voltmeter to the ‘AF from Rx´-signal located in the Handset Key connector (J803), pin
6 or solder pin P25-9 on the Filter Unit. Also connect a 1 KW load.

15. Adjust potentiometer R162-6 until the AF voltmeter reads 0.25 V

RMS

.

ADJUSTMENT AND CONTROL OF RECEIVER SENSITIVITY:

l. Select channel 6.

2. Connect the signal generator to antenna connector J801.

3. Connect distortion analyzer between the orange and green wire (ground) on Filter-Unit.

4. Set the signal generator to best sensitivity (12 dB SINAD).

5. Adjust potentiometer R16-6 (Interface Unit) to the best sensitivity.

6. Adjust coils L101, L102, and L103 to Max. signal to noise ratio (best sensitivity).

7. Check that the sensitivity is better than 0.8 uV EMF for 12 dB SINAD.

ADJUSTMENT OF SQUELCH:

1. Select channel 28.

2. Connect signal generator to antenna connector J801.

3. Set squelch control to Pos. 0.

4. Adjust signal generator to give -18 dB signal to noise ratio.

5. Set squelch control to Max. position (Pos. 8).

6. Adjust potentiometer R82-6 until the squelch just starts to cut the noise.

9545

PAGE 4-5

4 SERVICE RT2047 DSC - PART II

4.7 TROUBLE-SHOOTING

Trouble-shooting should only be attempted by persons with a sufficient technical background, who have
the necessary measuring instruments at their disposal, and who have carefully studied the operation
principles and structure of RT2047.

Commence by ascertaining whether the fault is somewhere in the antenna circuit, the power source, the
handset or in the transmitter - receiver unit.

For help with trouble-shooting in the RT2047, the section 2 CIRCUIT DESCRIPTION, contains diagrams,
principal descriptions and drawings showing the location of the individual components. In the diagrams
typical values are indicated for the DC and AC voltages, just as the test points are indicated in the
diagrams.

RT2047 has a number of trimming cores and trimmers, which must not be touched, unless adjustments
like specified under section 4.5 ADJUSTMENT PROCEDURE can be made.

When measuring in the units, short-circuits must be avoided as the transistors could be destroyed.
A great help for trouble-shooting is the TEST PROGRAMMES FOR RT2047 mentioned in section 3. of
the manual: INSTRUCTIONS FOR IDENTITY AND SERVICE PROGRAMMING OF VHF RT2047.

Therefore we recommend all service personal to read sections 3,4 and 5 where the fault finding facilities
in the test programmes are located.

4.8 REPLACEMENT OF COMPONENTS

Changing of transistors, diodes, resistors, capacitors and similar components will involve the use of a
small “pencil” soldering iron of 30 to 75 Watt rating. The soldering must be performed rapidly to avoid over
heating, and the use of a tin sucker is recommended, as there is a risk that both the components and the
printed circuit will be damaged otherwise.

4.9 REPLACEMENT OF MODULES

If a fault has been located to certain module time can be saved by replacing it and repairing it on a later
occasion.

PAGE 4-6

9545

4 SERVICE RT2047 DSC - PART II

4.10 NECESSARY ADJUSTMENTS AFTER REPLACEMENT OF A MODULE

4.10.1 REPLACEMENT OF RECEIVER UNIT MODULE 100

1. Adjustment of RF and IF amplifier, point 1 - 12.

2. Alignment of detector, telephone-amplifier, LF-power-amplifier and the AF from Rx buffer, point 1

- 15.

3. Adjustment and control of receiver sensitivity, point 1 - 7.

4. Adjustment of Squelch, point 1 - 6.

4.10.2 REPLACEMENT OF RX-SYNTHESIZER MODULE 200

Normally the module is adjusted from the factory. Just control the frequency on the soldering point for
FL01 to Rx on a simplex channels e.g. oh. 6 to be in Rx-mode: 156.300 MHz - 21.4 MHz = 134.900 MHz
and in Tx-mode: 156.300 MHz - 16.8 MHz = 139.500 Mhz.

4.10.3 REPLACEMENT OF TX-EXCITER MODULE 300

Follow the procedure in section 4.5.3. Adjustment of Tx-exciter:

1. Control of frequencies and DC-control voltage to VCO, point 1 - 5.

2. Adjustment of Tx-drive level, point 1 - 5.

4.10.4 REPLACEMENT OF TX-POWER AMPLIFIER MODULE 400

Follow the procedure in section 4.5.4. Adjustment of Tx-Power Amplifier about adjustment of output
power, point 1 - 7.

4.10.5 REPLACEMENT OF INTERFACE UNIT MODULE 6/600

1. Follow the procedure in section 4.5.1. Adjustment of Interface Unit about adjustment and control
of voltage regulators, point 1 - 9 and adjustment of the SELCALL TEST TONE.

2. Section 4.5.5. Adjustment of Modulation on Interface Unit, point 1-13.

3. Section 4.5.6. Adjustment of Receiver Unit about adjustment of Telephone-amplifier, LF-power­amplifier and the AF from Rx buffer amplifier, point 1 - 15, leaving out point 3, 5 and 8 and about
adjustment of squelch, point 1 - 6.

4. Section 4.5.4. Adjustment of TX-Power Amplifier, point 5 - 7.

9545

PAGE 4-7

4 SERVICE RT2047 DSC - PART II

PAGE 4-8

9545

4 SERVICE RT2047 DSC - PART II

4.11 PIN CONFIGURATION

9545

PAGE 4-9

4 SERVICE RT2047 DSC - PART II

4.12 PIN CONFIGURATIONS, BLOCK & SCHEMATIC DIAGRAMS FOR IC’S

MC6805U3 8-BIT MICROCOMPUTER

PIN ARRANGEMENT BLOCK DIAGRAM

MC68HC705C8 8-BIT MICROCOMPUTER

PIN ARRANGEMENT BLOCK DIAGRAM

PAGE 4-10

9545