TECHNICAL MANUAL FOR COMPACT VHF DSC RM2042

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3 SERVICE RM20423.3 PROPOSAL FOR NECESSARY TEST EQUIPMENTOSCILLOSCOPE:BandwidthSensitivityInput ImpedanceE.g. Philips typeDC-35 MHz2mV/div1 Mohm//20 pFPM3050PASSIVE PROBE:AttenuationInput ImpedanceCompensation RangeE.g. Philips type20 dB10 Mohm//15 pF10-30 pFPM8936/091MULTIMETER:Sensitivity DC (f.s.d.)100 mVInput Impedance10 MohmAccuracy DC (f.s.d.) 1.5%E.g. Philips typePM2505FREQUENCY COUNTER:Frequency Range100 Hz - 165 MHzResolution1 Hz at f = 100 MHzAccuracy 1 x 10 -7Sensitivity100 mV RMSInput Impedance1 Mohm/30 pFE.g. Philips type PM 6674RF SIGNAL GENERATOR:Frequency Range155 MHz - 165 MHzOutput Level: -124dBm - +7dBm (EMF: 0.25 µV RMS- 1 V RMS)Output Impedance50 ohmType of ModulationFMModulation FrequencyExternal: 1.3kHz, 2.1kHz / Internal: 1kHzE.g. Rohde & SchwarzCMTRF MODULATION METER:Frequency RangeInput ImpedanceE.g. Rohde & Schwarz155 MHz - 165 MHz50 ohmCMTLF SIGNAL GENERATOR:Frequency RangeOutput LevelOutput ImpedanceE.g. Hewlett-Packard100 Hz - 3 kHz10 mV - 1V50 ohmHP 8903BLF DISTORTION METER:Frequency Range1000 Hz, 1300 Hz, 2100 HzDistortion Range (f.s.d.) 0.1-10%Input Impedance100 kohmAccuracy (f.s.d.)5% of readingE.g. Hewlett-PackardHP 8903BPAGE 3-29403
3 SERVICE RM20423.4 TROUBLE SHOOTINGTrouble shooting should only be performed by persons with sufficient technical knowledge, who have thenecessary measuring instruments at their disposal, and who have carefully studied the operationprinciples and structure of the VHF DSC RM2042.The first thing to check is whether the fault is somewhere in the antennea circuit, the power source, thehandset, or inside the RM2042 it self.In order to help you during trouble shooting, the section 5. CIRCUIT DESCRIPTION AND SCHEMATICDIAGRAMS contains diagrams, principal descriptions, and drawings showing the location of theindividual components. Typical values for the DC and AC voltages are indicated in the diagrams, and alsothe test points are indicated in the diagrams.The RM2042 has a number of trimming cores and trimmers, which must not be touched unlessadjustments as specified in section 3.6. ADJUSTMENT PROCEDURE can be made.When measuring inside the unit, short circuits must be avoided as the transistors would then be spoiled.3.5 PERFORMANCE CHECKCHECK OF SYSTEM PERFORMANCEWith this check procedure it is possible to control the performance of a hole VHF DSC system, whichinclude the DSC unit it self, the VHF tranceiver, a GPS receiver and a printer.The idea of this test procedure is first to key-in a call sequence and hereby control the connections to thekey board and display, and the function of these modules. The next step is to send the DSC call to yourself, which is done in the ‘CALL’ menu by keying-in the MID-number of the unit it self. The DSC call is nowgenerated by the microprocessor and the FSK encoder at the receiver module. The FSK signal is thenmodulating the connected VHF radiotelephone and a short piece of wire connected to the antennaterminal at the VHF will be sufficient to transfer the RF-signal to the channel-70 receiver. The receivedsignal is then demodulated, decoded, sampled and finally recognized by the microprocessor. As aresponse to the receiption of the call, the microprocessor will write the received message to the printerand at the same time generate a gated tone sequence for the internal loudspeaker.The primary force of this test is that the function of all modules is controlled and that the connections forexternal equipment are checked as well. An other force is the fact that the test procedure does not requireany test equipment.The check procedure can also be used as a function check after the system has been installed.1. Connect the RM2042 to the VHF tranceiver, the printer and the GPS receiver (if available)2. Select the ‘FUNC’ menu and then the ‘Position’ menu. Control that the position data is updated bythe GPS receiver.3. Select the ‘CALL’ menu and press the ‘up-arrow’ button to key-in the MID-number of the DSC unitit self.4. Press ‘NEXT’ and select ‘Position’ by means of the ‘left-arrow’ and the ‘NEXT’ button.5. Press ‘NEXT’ and ‘SEND’ for transmission of the DSC call.6. The DSC call should now be received by the RM2042 and the alarm signal will be heard in theinternal loudspeaker. The RM2042 will write the received message to the printer.9403PAGE 3-3
Page 1: TECHNICAL MANUALFORCOMPACT VHF DSC
Page 5: RM2042CONTENTS1 INTRODUCTION1.1 GEN
Page 9 and 10: RM20421 INTRODUCTIONThe RM2042 VHF
Page 11 and 12: 1 INTRODUCTION RM20421.2 TECHNICAL
Page 13 and 14: 1 INTRODUCTION RM2042LASTThis butto
Page 15: 1 INTRODUCTION RM2042MICROPROCESSOR
Page 19: RM2042CONTENTS2 INSTALLATION2.1 MOU
Page 22 and 23: 2 INSTALLATION RM2042H2067 MOUNTING
Page 24 and 25: 2 INSTALLATION RM2042This mounting
Page 27 and 28: 2 INSTALLATION RM20422.5 ELECTRICAL
Page 29: RM2042CONTENTS3 SERVICE3.1 MAINTENA
Page 34 and 35: 3 SERVICE RM2042CHECK OF RECEIVER S
Page 36 and 37: 3 SERVICE RM2042CHECK OF TX AF DIST
Page 38 and 39: 3 SERVICE RM20423.6.3 ADJUSTMENT OF
Page 40 and 41: 3 SERVICE RM20423.9 NECESSARY ADJUS
Page 42 and 43: 3 SERVICE RM20423.10 PIN CONFIGURAT
Page 44 and 45: 3 SERVICE RM2042INTEGREATED CIRCUIT
Page 46 and 47: 3 SERVICE RM204271055/NEC & 82C55/O
Page 48 and 49: 3 SERVICE RM204274HC32 (SO-14 PACKA
Page 51: RM2042CONTENTS4 MECHANICAL DESCRIPT
Page 55: RM2042CONTENTS5 CIRCUIT DESCRIPTION
Page 58 and 59: 5 CIRCUIT DESCRIPTION AND SCHEMATIC
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5 CIRCUIT DESCRIPTION AND SCHEMATIC
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RM2042CONTENTS6 MICROTELEPHONE INST
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6 MICROTELEPHONE INSTALLATION RM204
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RM20427 PARTS LISTVHF DSC RM2042 SA
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7 PARTSLIST RM2042POSITION DESCRIPT
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TECHNICAL MANUAL FOR COMPACT VHF DSC RM2042

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