IEC 61097-8:1998
(Main)Global maritime distress and safety system (GMDSS) - Part 8: Shipborne watchkeeping receivers for the reception of digital selective calling (DSC) in the maritime MF, MF/HF and VHF bands - Operational and performance requirements, methods of testing and required test results
Global maritime distress and safety system (GMDSS) - Part 8: Shipborne watchkeeping receivers for the reception of digital selective calling (DSC) in the maritime MF, MF/HF and VHF bands - Operational and performance requirements, methods of testing and required test results
Specifies the minimum requirements for shipborne receivers intended to be connected to an external installation, including a decoder for digital selective calling (DSC), and used as receivers for watchkeeping on DSC channels on board ships operating in the maritime mobile MF, MF/HF and VHF bands.
General Information
Standards Content (Sample)
INTERNATIONAL
IEC
STANDARD
61097-8
First edition
1998-09
Global maritime distress
and safety system (GMDSS) –
Part 8:
Shipborne watchkeeping receivers for
the reception of digital selective calling (DSC)
in the maritime MF, MF/HF and VHF bands –
Operational and performance requirements,
methods of testing and required test results
Système mondial de détresse
et de sécurité en mer (SMDSM) –
Partie 8:
Récepteurs de veille de bord pour réception d’appel sélectif
numérique (ASN) dans la gamme des ondes hectométriques,
hectométriques et décamétriques, et métriques –
Exigences opérationnelles et de fonctionnement,
méthodes d’essai et résultats exigibles
Reference number
Numbering
As from 1 January 1997 all IEC publications are issued with a designation in the
60 000 series.
Consolidated publications
Consolidated versions of some IEC publications including amendments are
available. For example, edition numbers 1.0, 1.1 and 1.2 refer, respectively, to the
base publication, the base publication incorporating amendment 1 and the base
publication incorporating amendments 1 and 2.
Validity of this publication
The technical content of IEC publications is kept under constant review by the IEC,
thus ensuring that the content reflects current technology.
Information relating to the date of the reconfirmation of the publication is available
in the IEC catalogue.
Information on the subjects under consideration and work in progress undertaken by
the technical committee which has prepared this publication, as well as the list of
publications issued, is to be found at the following IEC sources:
• IEC web site*
• Catalogue of IEC publications
Published yearly with regular updates
(On-line catalogue)*
• IEC Bulletin
Available both at the IEC web site* and as a printed periodical
Terminology, graphical and letter symbols
For general terminology, readers are referred to IEC 60050: International Electro-
technical Vocabulary (IEV).
For graphical symbols, and letter symbols and signs approved by the IEC for
general use, readers are referred to publications IEC 60027: Letter symbols to be
used in electrical technology, IEC 60417: Graphical symbols for use on equipment.
Index, survey and compilation of the single sheets and IEC 60 617: Graphical symbols
for diagrams.
* See web site address on title page.
INTERNATIONAL
IEC
STANDARD
61097-8
First edition
1998-09
Global maritime distress
and safety system (GMDSS) –
Part 8:
Shipborne watchkeeping receivers for
the reception of digital selective calling (DSC)
in the maritime MF, MF/HF and VHF bands –
Operational and performance requirements,
methods of testing and required test results
Système mondial de détresse
et de sécurité en mer (SMDSM) –
Partie 8:
Récepteurs de veille de bord pour réception d’appel sélectif
numérique (ASN) dans la gamme des ondes hectométriques,
hectométriques et décamétriques, et métriques –
Exigences opérationnelles et de fonctionnement,
méthodes d’essai et résultats exigibles
IEC 1998 Copyright - all rights reserved
No part of this publication may be reproduced or utilized in any form or by any means, electronic or
mechanical, including photocopying and microfilm, without permission in writing from the publisher.
International Electrotechnical Commission 3, rue de Varembé Geneva, Switzerland
Telefax: +41 22 919 0300 e-mail: inmail@iec.ch IEC web site http: //www.iec.ch
Commission Electrotechnique Internationale
PRICE CODE
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International Electrotechnical Commission
For price, see current catalogue
– 2 – 61097-8 © IEC:1998(E)
CONTENTS
Page
FOREWORD . 4
Clause
1 Scope. 5
2 Normative references. 6
3 Definitions and abbreviations. 6
3.1 Definitions. 6
3.2 Abbreviations. 7
4 General and operational requirements . 8
4.1 General. 8
4.2 Construction. 8
4.3 Controls and indicators. 9
4.4 Software. 9
4.5 Memory. 10
4.6 Interfaces. 10
4.7 Marking and identification. 10
4.8 Instructions. 11
4.9 Warming-up period. 11
4.10 Safety precautions. 11
4.11 Compass safe distance . 11
5 Technical requirements. 12
5.1 Durability and resistance to environmental conditions . 12
5.2 Protection of the antenna input circuit. 12
5.3 Frequency bands and channels . 12
5.4 Mode of reception . 13
5.5 Scanning receivers. 13
5.6 Calling sensitivity. 14
5.7 Adjacent channel selectivity. 14
5.8 Co-channel rejection. 14
5.9 Intermodulation response. 14
5.10 Interference rejection, spurious response and blocking immunity . 14
5.11 Dynamic range. 15
5.12 Conducted spurious emissions into the antenna . 15
5.13 Frequency stability. 15
6 General test conditions. 15
6.1 General. 15
6.2 Test power source. 15
6.3 Normal test conditions. 15
6.4 Extreme test conditions . 16
6.5 Application of test signals to the receiver. 16
6.6 Choice of testing frequencies . 17
6.7 Test signals. 17
6.8 Measurement of bit error rate (BER). 17
6.9 Measurement uncertainty and interpretation of the measuring results . 18
61097-8 © IEC:1998(E) – 3 –
Clause Page
7 Environmental tests. 18
7.1 Procedure. 18
7.2 Performance check. 18
7.3 Vibration tests. 19
7.4 Temperature tests. 20
7.5 Corrosion test. 21
8 MF/HF watchkeeping receiver . 22
8.1 Calling sensitivity. 22
8.2 Adjacent channel selectivity. 23
8.3 Co-channel rejection. 23
8.4 RF intermodulation response. 24
8.5 Spurious response rejection . 24
8.6 Dynamic range. 25
8.7 Conducted spurious emissions into the antenna . 26
8.8 Protection of receiver antenna input circuits . 26
8.9 Stop/start. 27
8.10 Stop/start of scanning efficiency. 27
9 VHF watchkeeping receiver . 27
9.1 Calling sensitivity. 27
9.2 Adjacent channel selectivity. 28
9.3 Co-channel rejection. 28
9.4 Intermodulation response. 29
9.5 Spurious response and blocking immunity . 29
9.6 Dynamic range. 30
9.7 Conducted spurious emissions into the antenna . 30
10 EMC . 31
11 EMI . 31
Annexes
A Relationship between bit error rate (BER) input and symbol error rate (SER) output . 32
B Use of FSK demodulators for testing DSC watchkeeping receivers . 36
C Bibliography . 38
– 4 – 61097-8 © IEC:1998(E)
INTERNATIONAL ELECTROTECHNICAL COMMISSION
_________
GLOBAL MARITIME DISTRESS AND SAFETY SYSTEM (GMDSS) –
Part 8: Shipborne watchkeeping receivers for the reception of
digital selective calling (DSC) in the maritime MF,
MF/HF and VHF bands –
Operational and performance requirements, methods of
testing and required test results
FOREWORD
1) The IEC (International Electrotechnical Commission) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of the IEC is to promote
international co-operation on all questions concerning standardization in the electrical and electronic fields. To
this end and in addition to other activities, the IEC publishes International Standards. Their preparation is
entrusted to technical committees; any IEC National Committee interested in the subject dealt with may
participate in this preparatory work. International, governmental and non-governmental organizations liaising
with the IEC also participate in this preparation. The IEC collaborates closely with the International Organization
for Standardization (ISO) in accordance with conditions determined by agreement between the two
organizations.
2) The formal decisions or agreements of the IEC on technical matters express, as nearly as possible, an
international consensus of opinion on the relevant subjects since each technical committee has representation
from all interested National Committees.
3) The documents produced have the form of recommendations for international use and are published in the form
of standards, technical reports or guides and they are accepted by the National Committees in that sense.
4) In order to promote international unification, IEC National Committees undertake to apply IEC International
Standards transparently to the maximum extent possible in their national and regional standards. Any
divergence between the IEC Standard and the corresponding national or regional standard shall be clearly
indicated in the latter.
5) The IEC provides no marking procedure to indicate its approval and cannot be rendered responsible for any
equipment declared to be in conformity with one of its standards.
6) Attention is drawn to the possibility that some of the elements of this International Standard may be the subject
of patent rights. The IEC shall not be held responsible for identifying any or all such patent rights.
International Standard IEC 61097-8 has been prepared by IEC technical committee 80:
Maritime navigation and radiocommunication equipment and systems.
The text of this standard is based on the following documents:
FDIS Report on voting
80/191/FDIS 80/208/RVD
Full information on the voting for the approval of this standard can be found in the report on
voting indicated in the above table.
Annexes A, B and C are for information only.
A bilingual version of this standard may be issued at a later date.
61097-8 © IEC:1998(E) – 5 –
GLOBAL MARITIME DISTRESS AND SAFETY SYSTEM (GMDSS) –
Part 8: Shipborne watchkeeping receivers for the reception of
digital selective calling (DSC) in the maritime MF,
MF/HF and VHF bands –
Operational and performance requirements, methods of
testing and required test results
1 Scope
This part of IEC 61097 specifies the minimum requirements for shipborne receivers intended to
be connected to an external installation, including a decoder for digital selective calling (DSC),
and used as receivers for watchkeeping on DSC channels on board ships operating in the
maritime mobile MF, MF/HF and VHF bands allocated in the Radio Regulations of the
International Telecommunication Union (ITU) to the maritime mobile service, both in connection
with distress and safety communication and in connection with general communication.
These requirements include the relevant provisions of the Radio Regulations and recommenda-
tions ITU-R M.489, and ITU-R M.541, and relevant provisions of resolutions A.694, A.803,
A.804 and A.806 of the International Maritime Organization (IMO).
This standard also specifies technical characteristics, methods of testing and required test
results for dedicated watchkeeping receivers for use with radio installations in the GMDSS as
required by chapter IV of the International Convention for Safety of Life at Sea (SOLAS) 1974,
as amended, and with which IEC 60945 is associated. When a requirement in this standard
differs from IEC 60945, the requirement of this standard takes precedence.
This standard covers receivers with analogue or with digital DSC signal output interfaces or
with both.
DSC watchkeeping receivers can be either fixed frequency receivers or, in MF/HF bands,
scanning receivers.
They may be a separate equipment or be integrated with a DSC or radiotelephone equipment.
For integrated equipment this standard specifies the requirements and methods of testing of
the DSC watchkeeping receivers only. The DSC equipment or radiotelephone shall comply with
*
the requirements of the relevant standard, for example, IEC 61097-3 [3] , IEC 61097-7 [4] and
IEC 61097-9 [5] respectively.
NOTE – All requirements of this standard resulting from the above referenced IMO resolutions or ITU
recommendations are identified by quoting the number of the IMO resolution or ITU recommendation and relevant
paragraph in brackets following the requirement.
________
*
Figures in square brackets refer to the bibliography given in annex C.
– 6 – 61097-8 © IEC:1998(E)
2 Normative references
The following normative documents contain provisions which, through reference in this text,
constitute provisions of this part of IEC 61097. At the time of publication, the editions indicated
were valid. All normative documents are subject to revision, and parties to agreements based
on this part of IEC 61097 are encouraged to investigate the possibility of applying the most
recent editions of the normative documents indicated below. Members of IEC and ISO maintain
registers of currently valid International Standards.
IEC 60417:1973, Graphical symbols for use on equipment – Index, survey and compilation of
the single sheets
IEC 60945:1996, Maritime navigation and radiocommunication equipment and systems –
General requirements – Methods of testing and required test results
IEC 61162-1:1995, Maritime navigation and radiocommunication equipment and systems –
Digital interfaces – Part 1: Single talker and multiple listeners
ISO 3791:1976, Office machines and data processing equipment – Keyboard layouts for
numeric applications
ITU Radio Regulations:1997, as revised
ITU-R Recommendation M.489-2:1995, Technical characteristics of VHF radiotelephone
equipment operating in the maritime mobile service in channels spaced by 25 kHz
ITU-R Recommendation M.493-9:1997, Digital selective-calling system for use in the maritime
mobile service
ITU-R Recommendation M.541-8:1997, Operational procedures for the use of digital selective-
calling (DSC) equipment in the maritime mobile service
ITU-T Recommendation E.161:1993, Arrangement of digits, letters and symbols on telephones
and other devices that can be used for gaining access to a telephone network
ITU-R Recommendation SM.332-4:1994, Selectivity of receivers
ITU-T Recommendation V.11:1996, Electrical characteristic for balanced double-current
interchange circuits operating at signalling rates up to 10 Mbit/s
International Convention for the Safety of Life at Sea (SOLAS) 1974, as amended
IMO Resolution A.694:1991, General requirements for shipborne radio equipment forming part
of the global maritime distress and safety system and for electronic navigational aids
IMO Resolution A.803:1995, Performance standards for shipborne VHF radio installations
capable of voice communications and digital selective calling
IMO Resolution A.804:1995, Performance standards for shipborne MF radio installations
capable of voice communications and digital selective calling
IMO Resolution A.806:1995, Performance standards for shipborne MF/HF radio installations
capable of voice communications, narrow-band direct-printing and digital selective calling
ETR 028:1994, Radio Equipment and Systems (RES) – Uncertainties in the measurement of
mobile radio equipment characteristics
3 Definitions and abbreviations
3.1 Definitions
For the purpose of this standard, the following definitions apply:
3.1.1
assigned frequency
the centre of the frequency band assigned to a station
61097-8 © IEC:1998(E) – 7 –
3.1.2
continuous watch
the capability of receiving DSC calls not being interrupted other than for brief intervals when
the ship’s receiving capability is impaired or blocked by its own communications or when the
facilities are under periodical maintenance or checks (SOLAS/IV.2.1.2)
3.1.3
F1B
frequency modulation with digital information, without a subcarrier for automatic reception
3.1.4
J2B
single sideband with digital information, with the use of a modulating subcarrier, with the carrier
suppressed to at least 40 dB below peak envelope power
3.1.5
G2B
phase-modulation with digital information, with a subcarrier for automatic reception
3.1.6
performance check
a check of calling sensitivity
3.2 Abbreviations
For the purpose of this standard, the following abbreviations apply:
a.c. Alternating current
BER Bit error rate
d.c. Direct current
DSC Digital selective calling
e.m.f. Electromotive force
EMC Electromagnetic compatibility
EMI Electromagnetic immunity
ETR ETSI technical report
ETS European telecommunications standard
ETSI European Telecommunications Standards Institute
EUT Equipment under test
FSK Frequency shift keying
GMDSS Global maritime distress and safety system
IEC International Electrotechnical Commission
IMO International Maritime Organisation
ISO International Organization for Standardisation
ITU International Telecommunication Union
ITU-R ITU Radiocommunication Sector
ITU-T ITU Standardization Sector
MF Medium frequency
MF/HF Medium and high frequency
RF Radiofrequency
r.m.s. Root mean square
RR Radio regulations
S/N Signal-to-noise ratio
SER Symbol error rate
SOLAS Safety of life at sea
VHF Very high frequency
– 8 – 61097-8 © IEC:1998(E)
4 General and operational requirements
4.1 General
The equipment, in addition to meeting the requirements of the Radio Regulations, the relevant
ITU recommendations, the IMO performance standards and general requirements set out in
IMO resolution A.694 and detailed in IEC 60945, shall comply with the following requirements
and with the technical requirements contained in clause 5 of this standard (A.803/1, A.804/A.1,
A.806/A.1).
Requirements contained in clause 4 need not be verified by measurements. The manufacturer
shall declare that compliance with these requirements is achieved and shall provide relevant
documentation.
The manufacturer shall also declare the composition of the equipment and the relevant
category of IEC 60945 for each unit.
4.2 Construction
4.2.1 General
The equipment shall be so constructed that it is capable of:
– keeping continuous watch on DSC channels (A.803/2.4.6, A.804/A.2.4.6, A.806/A.2.4.7);
– being operated readily and in accordance with the requirements of this standard.
4.2.2 Design
In all respects, the mechanical and electrical design and construction, and the finish of the
equipment shall conform with good engineering practice, and the equipment shall be suitable
for use on board ships at sea.
The equipment shall be designed for continuous operation.
4.2.3 Accessibility
All parts of the equipment that are subject to inspection and maintenance adjustments shall be
easily accessible (A.694/8.2).
Components shall be easily identifiable either by markings within the equipment, or with the aid
of technical descriptions.
4.2.4 Calibration and maintenance
The equipment shall be so constructed that its main modules can be replaced easily and put
into operation without elaborate calibration or readjustment (A.694/8.1).
4.2.5 Antenna static protection
In order to provide protection against damage due to static voltages that may appear at the
input of the receiver, there shall be a d.c. path from the antenna terminal to ground not
exceeding 100 kΩ.
61097-8 © IEC:1998(E) – 9 –
4.2.6 Digital input panels
Where a digital input panel with the digits 0 to 9 is provided, the digits preferably shall be
arranged to conform with recommendation ITU-T E.161. However, where an alphanumeric key-
board layout, as used on office machinery and data processing equipment, is provided, the
digits 0 to 9 may, alternatively, be arranged to conform with ISO 3791 (A.694/3.6).
4.3 Controls and indicators
4.3.1 General
The number of operational controls, their design and manner of functioning, location, arrange-
ment and size should provide for simple, quick and efficient operation. The controls shall be
arranged in a manner which minimizes the chance of inadvertent activation (A.694/3.1).
All operational controls shall permit normal adjustments to be easily performed (A.694/3.2).
The user shall not have access to any control which may impair the technical characteristics of
the equipment if wrongly set.
4.3.2 Identification
All operational controls and indicators shall be easy to identify and read from the position at
which the equipment is normally operated (A.694/3.2).
The controls and indicators shall be identified in English. Symbols as specified in IEC 60417
may be used in addition to the identification in English.
4.3.3 Protection against possible maladjustment
Controls not required for normal operation shall not be readily accessible (A.694/3.2).
Operational controls, the inadvertent exercise of which could switch off the equipment, lead to
its performance degradation or to false indications not obvious to the operator, shall be
protected especially against unintentional operation.
4.3.4 Light sources
Equipment with controls and indicators shall be provided with adequate adjustable illumination
to enable identification of controls and facilitate reading of indicators at all times. Means shall
be provided for dimming the output of any equipment light source (A.694/3.3).
4.3.5 Operation
The design of the equipment shall be such that misuse of the controls shall not cause damage
to the equipment or injury to personnel (A.694/3.4).
4.4 Software
Facilities shall be provided to protect all operational software incorporated in the equipment.
Any software required in an equipment to facilitate operation, including that for its initial activa-
tion/reactivation, shall be permanently installed within the equipment, in such a way that it is
not possible for the user to have access to this software.
Means shall be provided to monitor the operational software of the equipment automatically at
appropriate regular intervals, and to activate an alarm in the event of non-automatic
recoverable failure.
– 10 – 61097-8 © IEC:1998(E)
4.5 Memory
Pre-programmed DSC distress calling frequencies and information inherent to the operation of
the equipment shall be stored in non-volatile devices.
If the equipment contains information in operator programmable memory devices, such devices
shall be protected from interruptions in the power supply up to at least 10 h duration.
4.6 Interfaces
4.6.1 DSC signal output – analogue interface
For equipment designed for analogue DSC signal output to an external DSC decoder, the audio
frequency signal output shall have an impedance of 600 Ω, balanced and free of earth, and
the closed circuit level shall be adjustable to any r.m.s. voltage between 0,245 V and 2,450 V
(0 dBm ± 10 dB).
The higher frequency corresponds to the B-state and the lower frequency corresponds to the
Y-state of the signal elements.
4.6.2 DSC signal output – digital interface
For equipment designed for binary signal output to an external DSC decoder, the logic level of
the digital signal output shall be compatible with recommendation ITU-T V.11.
The B-state shall be the logic “0”, and the Y-state shall be the logic “1”.
4.6.3 Operational interfaces
Where provided:
– interfaces for stop and start of the scanning sequence of scanning receivers shall comply
with recommendation ITU-T V.11;
– interfaces for frequency control or read-out of scanning receivers shall comply with IEC 61162-1.
Additional interfaces may be provided but connection of, or failure within, any external circuits
shall not degrade the performance of the equipment (A.694/3.5).
4.7 Marking and identification
Each unit of the equipment shall be marked externally with the following information which,
where practicable, should be clearly visible in the normal installed position:
– identification of the manufacturer;
– equipment type number or model identification under which it was type tested;
– serial number of the unit (A.694/9);
– details of the power supply from which the equipment is intended to operate.
Alternatively, the marking may be presented on a display on equipment start-up.
The title and version of the installed software system shall be either marked or displayed on
command on the equipment.
When the marking and the title and version of the software are shown only on the display, such
information shall also be included in the equipment manual.
61097-8 © IEC:1998(E) – 11 –
The DSC frequency or channel to which the equipment is tuned or programmed shall be clearly
indicated. For programmable scanning receivers, read-out or print-out on the receiver controller
shall be used.
4.8 Instructions
Adequate information shall be provided to enable the equipment to be properly operated and
maintained.
Operating and servicing manuals shall:
– at least be written in English;
– identify the category (protected from or exposed to the weather) of the equipment or units
to which they refer;
– in the case of equipment so designed that fault diagnosis and repair down to component level
are practicable, provide full circuit diagrams, component layouts, a component parts list;
– in the case of equipment containing complex modules in which fault diagnosis and repair
down to component level are not practicable, contain sufficient information to enable a
defective complex module to be located, identified and replaced. Other modules and those
discrete components which do not form part of modules shall also meet the requirements
above (A.694/8.3).
4.9 Warming-up period
The equipment shall be operational and shall meet the requirements of this standard 1 min
after switching on (A.803/5, A.804/C.5, A.806/C.5).
4.10 Safety precautions
4.10.1 Excessive current and voltage
Means shall be incorporated for the protection of equipment from the effects of excessive
current and voltage and accidental reversal of the power supply polarity or phase sequence
(A.694/4.2).
4.10.2 Earthing
Means shall be provided for earthing exposed metallic parts of the equipment, but the
equipment shall not cause any terminal of the source of electrical energy to be earthed
(A.694/7.2).
4.10.3 Protection
As far as practicable, accidental access to dangerous voltages shall be prevented. All parts
and wiring in which the direct or alternating voltages or both (other than radiofrequency
voltages) combine to give a peak voltage greater than 50 V, shall be protected against
accidental access and shall be isolated automatically from all sources of electrical energy when
the protective covers are removed. Alternatively, the equipment shall be so constructed that
access to such voltages may only be gained after having used a tool for this purpose, such as
a spanner or screwdriver, and warning labels shall be prominently displayed both within the
equipment and on protective covers.
4.11 Compass safe distance
The compass safe distance to a standard or steering magnetic compass shall be stated on the
equipment or in the manual (A.694/6.3).
The determination of the compass safe distance shall be performed in accordance with IEC 60945.
– 12 – 61097-8 © IEC:1998(E)
5 Technical requirements
5.1 Durability and resistance to environmental conditions
The equipment shall be capable of continuous operation under the conditions of various sea
states, vibration, humidity and of temperature likely to be experienced in ships (A.694/5).
5.2 Protection of the antenna input circuit
The receiver shall not suffer damage when an unmodulated radiofrequency signal at an input
level of 30 V r.m.s. at any frequency in the range 100 kHz to 27,5 MHz is applied to its antenna
input terminal for a period of 15 min.
5.3 Frequency bands and channels
The equipment can be designed as a single-frequency receiver, as a multiple-frequency
receiver or as a scanning receiver in one or more of the frequency bands:
MF: 1 605 kHz to 4 000 kHz;
HF: 4 MHz to 27,5 MHz;
VHF: 156 MHz to 174 MHz.
MF and HF DSC frequencies shall be designated in terms of the assigned frequency
(A.804/B.1.2, A.806/B.1.2).
On MF and HF DSC calling frequencies for distress, urgency and safety calling are different
from those for general communication calling.
The MF and HF DSC distress calling frequencies are:
– 2 187,5 kHz; 4 207,5 kHz; 6 312 kHz; 8 414,5 kHz; 12 577 kHz and 16 804,5 kHz
(M.541/A5.1).
For general communication the international MF calling frequency shore-to-ship and ship-to-
ship is 2 177 kHz and ship-to-shore is 2 189,5 kHz.
For general communication the international HF calling frequencies shore-to-ship first choice
are:
– 4 219,5 kHz; 6 331 kHz; 8 436,5 kHz; 12 657 kHz; 16 903 kHz; 19 703,5 kHz; 22 444 kHz
and 26 121 kHz (M.541/A5.2.2).
For general communication the international HF calling frequencies ship-to-ship and ship-to-
shore first choice are:
– 4 208 kHz; 6 312,5 kHz; 8 415 kHz; 12 577,5 kHz; 16 805 kHz; 18 895,5 kHz; 22 374,5 kHz;
and 25 208,5 kHz ( M.541/A5.2.1).
Additional frequencies allocated to coast stations are:
– 4 220 kHz; 6 331,5 kHz; 8 437 kHz; 12 657,5 kHz; 16 903,5 kHz; 19 704 kHz; 22 444,5 kHz;
26 121,5 kHz;
– 4 220,5 kHz; 6 332 kHz; 8 437,5 kHz; 12 658 kHz; 16 904 kHz; 19 704,5 kHz; 22 445 kHz;
26 122 kHz (M.541/A5.2.2).
61097-8 © IEC:1998(E) – 13 –
Additional frequencies allocated to ship stations are:
– 4 208,5 kHz; 6 313 kHz; 8 415,5 kHz; 12 578 kHz; 16 805,5 kHz; 18 899 kHz; 22 375 kHz;
25 209 kHz;
– 4 209 kHz; 6 313,5 kHz; 8 416 kHz; 12 578,5 kHz; 16 806 kHz; 18 899,5 kHz; 22 375,5 kHz;
25 209,5 kHz (M.541/A5.2.1).
For general communication calling only, other MF and HF working channels may also be used
(M.541/A5.3).
Watchkeeping receivers for the MF DSC frequency for distress, urgency and safety calling
shall be single-frequency receivers for 2 187,5 kHz (A.804/A.2.4.6).
MF and MF/HF scanning receivers shall be designed for scanning of up to six frequencies
for either DSC distress calling only, or for DSC general communication calling only
(A.806/A.2.4.7).
On VHF the calling channel for distress, urgency and safety calling as well as for general
communication calling is channel 70 (M.541/A4.1.1).
Watchkeeping receivers for VHF distress, urgency and safety calling frequencies shall be
single-channel receivers set to channel 70 (A.803/2.4.6).
For general communication calling only, VHF watchkeeping receivers may be switched to other
channels of appendix S18 of the Radio Regulations (M.541/A5.3).
5.4 Mode of reception
Equipment for reception of MF and HF DSC transmissions shall provide for classes of emission
F1B or J2B (A.804/C.1.3, A.806/C.1.3).
Equipment for reception of VHF DSC transmissions shall provide for class of emission G2B
(see RR appendix 19) (A. 803/3.4).
5.5 Scanning receivers
5.5.1 Scanning sequence
An MF/HF scanning receiver shall be able to complete a scanning sequence within 2 s
(A.806/A.2.4.7).
5.5.2 Scanning frequencies
Scanning watchkeeping receivers shall be dedicated to either scan DSC distress frequencies
or to scan DSC frequencies for general communication. It shall not be possible to have both
DSC distress frequencies and DSC frequencies for general communication in one scanning
sequence.
5.5.2.1 DSC distress frequencies
Scanning watchkeeping receivers for MF/HF DSC distress frequencies shall scan the
frequencies 2 187,5 kHz and 8 414,5 kHz and at least one other HF DSC distress frequency
listed in 5.3 up to a total of six frequencies in the scanning sequence (SOLAS IV/10.2.2).
– 14 – 61097-8 © IEC:1998(E)
5.5.2.2 DSC frequencies for general communication
Scanning watch receivers for MF and HF DSC frequencies for general communication may
scan any frequency up to a total of six frequencies in the scanning sequence.
5.5.3 Stop/start of scanning
The scanning receiver shall be provided with means for stop and start of the scanning under
the control of an external DSC equipment. Such control may be provided by either:
– a stop/start signal in accordance with recommendation ITU-T V.11. The stop signal shall be
logic 0 and the start signal shall be logic 1; or
– by direct frequency commands in accordance with IEC 61162-1, or both.
5.5.4 Frequency information
The selected receiver frequency shall be clearly identifiable (A.806/C.1.2).
Means shall be provided for automatic transfer of information of the frequency or channel on
which the scanning has stopped for use and display in an external installation (normally a DSC
equipment). The interface for such transfer shall be in accordance with IEC 61162-1.
5.6 Calling sensitivity
–2
The sensitivity of the receiver shall be such as to obtain an output character error rate of 10
or less for an input signal of +5 dBμV (e.m.f.) on MF and 0 dBμV (e.m.f.) on HF and VHF
(A.804/C.3, A.806/C.3).
5.7 Adjacent channel selectivity
The adjacent channel selectivity shall be 40 dB for MF/HF and 70 dB for VHF.
5.8 Co-channel rejection
The co-channel rejection ratio shall be between –10 dB and 0 dB.
5.9 Intermodulation response
The intermodulation response for MF and HF equipment shall be such as to obtain a specified
BER at a level of +70 dBμV for each of the two unwanted input signals.
The intermodulation response ratio for VHF equipment shall be 65 dB (M.489/1.3.4).
5.10 Interference rejection, spurious response and blocking immunity
The interference rejection for MF and HF equipment shall be such as to obtain a specified BER
at a level of the unwanted input signal of +60 dBμV.
The spurious response immunity for VHF equipment shall be 70 dB (M.489/1.3.3).
The blocking level shall be not less than +90 dBμV for MF/HF equipment and +93 dBμV for
VHF equipment.
61097-8 © IEC:1998(E) – 15 –
5.11 Dynamic range
The dynamic range shall be 80 dB for MF/HF equipment and 100 dB for VHF equipment.
5.12 Conducted spurious emissions into the antenna
Conducted spurious emissions into the antenna shall not exceed 2 nW (M.489/1.3.5).
5.13 Frequency stability
For MF/HF equipment, the receiver frequency shall at all times remain within 10 Hz of the
required frequency following the warming-up period (A.804/C.2, A.806/C.2).
6 General test conditions
6.1 General
Conformance testing shall be carried out under normal test conditions and also, where stated,
under extreme test conditions.
The equipment under test (EUT), when integrated with a DSC equipment or a radiotelephone,
shall be provided with an accessible test point at the watchkeeping receiver analogue or digital
signal output.
6.2 Test power source
During conformance testing the equipment shall be supplied from a test power source, capable
of producing normal and extreme test voltages as specified in 6.3.2 and 6.4.2.
For the purpose of tests, the voltage of the power supply shall be measured at the input
terminals of the equipment.
If the equipment is provided with a power cable permanently connected, the test voltage shall
be that measured at the point of connection of the power cable to the equipment.
During tests, the test power source voltages shall be maintained within a tolerance of ±3 %
relative to the voltage at the beginning of each test.
6.3 Normal test conditions
6.3.1 Normal temperature and humidity
The normal temperature and humidity conditions for tests shall be any convenient combination
of temperature and humidity within the following ranges:
– temperature: +15 °C to +35 °C;
– relative humidity: 20 % to 75 %.
6.3.2 Normal test power source
6.3.2.1 Mains voltage and frequency
The normal test voltage for equipment to be connected to the a.c. mains shall be the declared
voltage and frequency or any one of the declared voltages and frequencies for which the
equipment was designed.
The frequency of the test power supply shall be 50 Hz ± 1 Hz.
– 16 – 61097-8 © IEC:1998(E)
6.3.2.2 Secondary battery power sources
Where the equipment is designed to operate from a battery, the normal test voltage shall be
the nominal voltage of the battery (e.g. 12 V, 24 V, etc.).
6.3.2.3 Other power sources
For operation from other power sources, the normal test voltage shall be as stated by the
manufacturer.
6.4 Extreme test conditions
6.4.1 Extreme temperature
When testing under extreme conditions, the measurements shall be carried out at –15 °C and
+55 °C for equipment intended for mounting below deck, and –25 °C and +55 °C for equipment
intended for mounting above deck.
Before making measurements, the equipment shall have reached thermal balance in the test
chamber. The equipment shall be switched off during the temperature stabilizing period. The
sequence of measurements shall be chosen, and the humidity content in the test chamber shall
be controlled, so that excessive condensation does not occur.
6.4.2 Extreme values of test power source
6.4.2.1 Mains voltage and mains frequency
The extreme test voltages for equipment to be connected to an a.c. mains supply shall be the nominal
mains voltage ±10 %. The extreme frequency of the test power supply shall be 50 Hz ± 1 Hz.
6.4.2.2 Secondary battery power sources
When the equipment is intended for operation from a secondary battery power supply,
the extreme test voltage shall be 1,3 and 0,9 times the nominal voltage of the battery (e.g.
12 V, 24 V, etc.).
6.4.2.3 Other power sources
For equipment using other power sources, the extreme test voltages shall be as stated by the
manufacturer.
6.5 Application of test signals to the receiver
6.5.1 Arrangement
For the purpose of conformance testing, the receiver shall meet the requirements of this
standard when connected to sources of test signals so that the impedance presented to the
receiver input is 50 Ω resistive. In the frequency range 1 605 kHz to 4 000 kHz, at the request
of the manufacturer, a network consisting of a 10 Ω resistor in series with a 250 pF capacitor
may be used.
The arrangement used shall be stated in the test report.
This shall in no way imply that the receiver shall operate satisfactorily only with antennas
having these impedance characteristics.
61097-8 © IEC:1998(E) – 17 –
6.5.2 Sources
Sources of test signals for application to the receiver input shall be connected through a
network as specified in 6.5.1. This requirement shall be met irrespective of whether one, two or
more test signals are applied to the receiver simultaneously. In the case of multiple test
signals, steps shall be taken to prevent any undesirable effects due to interaction between the
signals in the generators or other sources.
6.5.3 Levels
The levels of test signals shall be expressed in terms of the e.m.f. that would exist at the
output terminals of the source, including the associated network referred to in 6.5.1.
6.6 Choice of testing frequencies
The testing frequencies shall be for:
– MF watchkeeping receivers: 2 187,5 kHz;
– MF/HF scanning receivers: 8 414,5 kHz;
– VHF watchkeeping receivers: 156,525 MHz (channel 70).
6.7 Test signals
Except where otherwise stated, radiofrequency test signals applied to the receiver input shall
be as described in the following subclauses.
A standard test signal shall simulate the DSC modulation specified in recommendation ITU-R
M.493 and shall be of sufficient duration for the measurements to be performed, or it shall be
possible to repeat it without interruption as long as necessary to make the measur
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