Ericsson LBI-38756 User Manual

Mobile Communications

LBI-38652

MDS

148-174 MHz MOBILE RADIO
COMBINATION

TABLE OF CONTENTS

MAIN BOARD ASSEMBLY . . . . . . . . . . . . . . . . . . . LBI-38756

FRONT PANEL ASSEMBLY . . . . . . . . . . . . . . . . . . . LBI-38757

POWER AMPLIFIER ASSEMBLY . . . . . . . . . . . . . . . LBI-38758

SERVICE SECTION . . . . . . . . . . . . . . . . . . . . . . . LBI-38759

Maintenance Manual

Printed in U.S.A.

LBI-38652 LBI-38652

SPECIFICATIONS

TABLE OF CONTENTS

Page

SPECIFICATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

GENERAL

Frequency Range Trans mit: 148-174 M H z

Receive: Same as Transmit

PACKAGE NUMBERS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

OPTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

RADIO DESCRIPTIO N . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

MAIN BOARD ASSEMBLY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

FRONT PANEL ASSEMBLY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

POWER AMPLIFIER ASSEMBLY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

FEATURES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

PC PROGRAMMABLE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

EXTERNAL SPEAKER (Optional) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

BATTERY POWER . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

EASY ACCESSIBILITY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

SERVICE AIDS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

DET AILED TYPE 99 OPERATION AND PROGRAMMING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

GE TYPE 99 FORMAT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

MOTOROLA FORMAT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

MECHANICAL PARTS BREAKDOWN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

MECHANICAL PARTS LIST . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

FIGURES

Figure 1 - MDS Conventional Radio Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

TABLES

T a ble 1 - Channel Guard Tone Frequencies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Table 2 - Primary and Eq uival ent Di gital Codes (OCTAL) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Table 3 - To ne Groups . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

T a ble 4 - Tone Generator Frequencies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

Table 5 - Motorola Type Coder Numb ers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

Table 6 - Motorola Group Call Tone Groups (TG) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

Table 7 - Motorola Group Call Tone Groups (TG) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

Channel Spacing 25 kHz
Frequency Stability ±5.0 ppm
Operating Temperat ure Range -30 to +60°C
Battery Voltage 13.6 volts ± 10% (meets specs)

± 20% (operational)

Radio Current Drain OFF: 0.01 amps

Rx Squelched: 0.9 amps
RxOn: 1.5 amps
Tx On: 10.0 amps

Size 170mm W x 216mm L x 53mm H

TRANSMITTER

Tx T wo Frequency Spread 26 MHz
RF Power Output 40 watts (+ 146 dBm, Adjustable 20 to 40 watts)
Maximum Deviation ±5% kHz peak
Tx Duty Cycle 20% Intermittent (EIA)
FM Hum and Noi s e (E IA ) -45 dBc ma x imum
Audio Distortion 5% @ 300 Hz, 3% @ 1kHz, 5% @ 3kHz
RF Load Impedance 50 ohms
Audio Sensitivity 80 mV ±3 dB
Audio Frequency Response Within + 1 ,-3 dB of a 6db/octave pre-emphasis,

300-3000 Hz (EIA)

Spurious Emissions

Conducted
Radiated

RECEIVER

Receiver coverage
Factory Tuned

Rx T w o F req Spread 18 MHz (No degrad at ion)
Channel Spacing 25/30 kHz
Sensitivity (12 dB SINAD) -117 dBm (.30 µV)

-16.5 dBm max ( M eets DOC & FCC)

-13 dBm max (FCC)

148-174 MHz
150-168 MHz

Copyright © April 1992, Ericsson GE Mobile Communications, Inc.

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LBI-38652 LBI-38652

SPECIFICATIONS (Cont.)

Spurious Emissions

Radiated Meets FCC requirements

Conducted -57 dBm maximum
Rx Spurious Res ponse 70 dB minimum
Adj Ch(2-Sig) Selectivity -75 dB max @ 30 kHz (EIA)
Intermodulation Atten uation -75 dB minimum
Rx Modulation Acceptance ± 7 kHz minimum
Audio Distortion 2% maximum @ 0.5 Watt (EIA)

10% maximum @ 4 W atts and 1 kHz

Audio Frequency Response Within + 2,-8 of a 6dB/octave de-emphases,

300-3000 Hz (EIA)

Rx Hum and Noise

Unsquelched -50 dB maximum

Squelched -70 dB maximum
Audio Output Power 4 watts, @ <10% Distortion
Speaker Impedance 4 ohms

MDS RADIO PACKAGE NUMBERS

PACKAGE NUMBER DESCRIPTION

TLH22 VHF 2 CHANNEL, 40 WA T T
TLH28 VHF 8 CHANNEL, 40 WA T T

OPTIONS

OPTION NUMBER DESCRIPTION

MC3G DESK TO P MIC

ANIR 1/4 WAVE, ROOF M T ANTENNA W/TNC CONNECTOR

ZM3L EXTERNAL WEA THERPROOF SPEAKER AND CABLE

LS1F MIL SPEC SPEAKER, 4 OHMS, 5 x 5
CD1E SPEAKER CABLE
PD1A NOISE FILTER KIT
SU1C ALARM RELAY KIT
EC1A DOC POWER SET

MA1L DESK TOP RADIO MOUNTING W EDGE

PS1D 240 VAC-12 VDC, 13A 50/60 Hz Power Supply
PS5K 120 VAC-12 VDC, 13A 50/60 Hz Power Supply

INTRODUCTION

The Ericsson GE Conventional MDS VHF Radio is a rug­ged two-way FM mobile radio which operates in the 148-174
MHz frequency band. The MDS is a wide band synthesized ra­dio utilizing microcomputer technology to provide reliable
high quality simplex two-way mobile communications. Its
transmitter output power level is 40 watts over the wide band­width of each split. The receiver has an allowable 12 MHz
maximum receive channel separation. There are two versions
available, a 2-channel and an 8-channel. The basic radio pack­age includes the following featu re s:

• Microprocessor Control

• Synthesized RF Channel selection (frequency control)

• 7-Segment LED Channel Display

• Multi-tone Channel Guard (CTCSS) Encode/D ec o d e

• Multi-code Digital Channel Guard (DCG)

Encode/Decode

• Automatic Hook Switch Channel Guard Disable

• Channel Activity Sensing (CAS)

• Carrier Control Timer (CCT)

• 5 ppm frequency stability

• Type 99 Tone Decode

• Field Programmable with PC

• Fixed Squelch, threshold programmable

• Internal 4-watt Speaker, with volume control

• Front Mounted Microphone Connector

• Rear Mounted Antenna TNC Connector

• Rear entry power connections

• ANI Encode

The small size of the MDS radio makes it ideal for front
mounting in conventional vehicles. The radio is operated with
a simple hand held microphone in combination with the fol­lowing operating controls, all loca ted on t h e front p an el:

• Power ON/OFF Switch

• Channel UP/DOWN Selector

• Volume UP/DOWN Control

• Monitor Switch for Channel Guard Disable

• Type 99 Tone RESET S w i tch , to reset the tone d ecoder.

Refer to the Operator’s Manual LBI-38651 for a complete
description of the operating proced ures.

RADIO DESCRIPTION

MAIN BOARD ASSEMBLY

A sturdy aluminum casting houses the Main Board Assem­bly N29/85154001920. There is complete accessibility to the
Main Board with the radio’s top and bottom cover s removed.
The Main Board contains the following circuits:

• Microprocessor and associated Logic

• Frequency Synthesizer

• Transmitter Excite r

• Receiver

• Audio Processing (for both transmit and receive paths)

• Tone and Squelch Processing (for both transmit and

receive paths)

• Voltage Regulators

Logic Circuitry

The radio’s logic circuitry includes the 80C535 microproc­essor with associated EPROM and Electrically Erasable
PROM (EEPROM) memory and latch circuitry. The Micro­processor controls the functions of the transmitter, the receiver,
the inputs from the operator and the outputs to the operator.

Synthesizer

A programmable Synthesizer generates both transmit and
receive operating frequencies. It includes a synthesizer chip, a
dual modulas counter, a temperature compensated reference
oscillator (TCXO) and a voltage controlled oscillator (VCO);
all part of an operating phase lock loop, with its requisite loop
filter.

Transmitter

The radio transmitter includes the Synthesizer’s modulated
VCO and the fixed tuned exciter amplifiers. The e xc i te r a mpli­fiers are wideband, covering the VHF band without retuning.
The exciter output is fed to the Power Amplifier Board through
a coax cable. The exciter provides 35 dB of gain to drive the
Power Amplifier with 2 watts. The transmitter output level at
the antenna connector is factory set for a rated output power of
40 watts. The power control circuit detects the powe r o u tp u t of
the Power Amplifier. Using the error signal, the power control
circuit varies the DC supply voltage to the first stage of the ex­cite r. T his will hold the tr ansmitte r output lev el c onstan t.

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