ISO 9876:2015

INTERNATIONAL ISO
STANDARD 9876
Third edition
2015-03-15
Ships and marine technology —
Marine facsimile receivers for
meteorological charts
Navires et technologie maritime — Récepteurs marins de
transmissions par télécopie des cartes météorologiques
Reference number
©
ISO 2015
© ISO 2015
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ii © ISO 2015 – All rights reserved

Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Requirements . 3
4.1 Construction . 3
4.2 Performance standards for recording unit . 3
4.3 Performance standards for radio receiver . 4
4.4 General requirement of the radio receiver and the recording unit . 4
5 Test methods and required test results . 5
5.1 General test requirements . 5
5.2 General conditions of measurement . 5
5.3 Construction . 5
5.4 Performance tests for recording unit . 5
5.5 Performance tests for radio receiver . 6
5.6 Other tests . 7
6 Marking . 8
7 Information . 8
Bibliography . 9
Foreword
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different types of ISO documents should be noted. This document was drafted in accordance with the
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The committee responsible for this document is ISO/TC 8, Ships and marine technology, Subcommittee
SC 6, Navigation and ship operations.
This third edition cancels and replaces the second edition (ISO 9876:1997), which has been technically
revised.
iv © ISO 2015 – All rights reserved

INTERNATIONAL STANDARD ISO 9876:2015(E)
Ships and marine technology — Marine facsimile receivers
for meteorological charts
1 Scope
This International Standard specifies the construction, performance, type testing, and inspection for
a ship borne marine facsimile receiver that receives meteorological charts transmitted by “Facsimile
transmission of meteorological chart over radio circuits” stated in accordance with World Meteorological
Organization (WMO) publication No. 386, Part III-5.
This International Standard applies to ship borne radio facsimile receivers for the reception of
meteorological charts and other graphical representation of meteorological conditions intended as an
aid to navigation at sea.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and are
indispensable for its application. For dated references, only the edition cited applies. For undated
references, the latest edition of the referenced document (including any amendments) applies.
IEC 60945, Maritime navigation and radiocommunication equipment and systems – General requirements
–Methods of testing and required test results
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
dead sector
part of scanning line unavailable for picture signal transmissions the criteria of which are within
4,5 % ± 0,5 % of the length
3.2
facsimile
process, or the result of the process, by which fixed graphic charts are scanned and the information is
converted to electric signals which are used remotely to produce a copy of the chart in record form
3.3
F3C
radio emissions designation from ITU Radio Regulations Appendix 1 for frequency modulation, single
channel having analog information, facsimile
3.4
index of cooperation
IOC
value of the index of cooperation, M, is defined as follows:
ML= F /π
where
L is the length of the scanning line, in centimetres;
F is the density of the scanning line, in reciprocal centimetres.
3.5
IOC selection signal
signal for automatic IOC selection in the facsimile receiver which is accomplished by transmission of
alternating black and white signals lasting for 5 s to 10 s with the following frequencies:
— 300 Hz for IOC 576;
— 675 Hz for IOC 288 (or IOC 576 with alternate line scanning).
Note 1 to entry: The envelopes of the signal are approximately rectangular.
3.6
meteorological chart
chart portraying the state of the weather (such as weather conditions, wind force and direction, high or
low atmospheric pressure, weather front and isobar) at a particular time over a wide area
3.7
phasing
adjusting the phase of the independent synchronous power source so as to be able to receive the weather
chart in its correct position
3.8
phasing signal
signal for automatically phasing the facsimile receiver accomplished by a 30 s transmission of alternating
black and white signals with the following frequencies:
— 1 Hz for 60 lines per minute (60 r/min);
— 1,5 Hz for 90 lines per minute (90 r/min);
— 2 Hz for 120 lines per minutes (120 r/min).
Note 1 to entry: This signal may also be used for automatic starting, automatic selection of scanning frequency,
and automatic adjustment of recording levels.
Note 2 to entry: The wave form of this signal is either symmetrical, i.e. black and white, each lasting half the
scanning line, or symmetrical with the white lasting for 5 % and black for 95 % of the scanning line.
3.9
remote control signal
control signal for operating the apparatus from a distance
Note 1 to entry: The remote control signals for operating the facsimile receiver for meteorological charts include
the phasing signal, the IOC selection signal, and stop signal.
3.10
SND/N
value of signal plus noise plus distortion to noise ratio
2 © ISO 2015 – All rights reserved

3.11
SND/ND
value of signal plus noise plus distortion to noise plus distortion ratio
3.12
spurious responses
ratio of the input level of an unwanted signal at the frequency of the spurious response to the input level
of a wanted signal when the wanted and unwanted signals individually produce the same SND/N or
SND/ND ratio at the receiver output
3.13
stop signal
transmission of 5 s of alternating black and white signals at 450 Hz, followed by 10 s of signal
corresponding to continuous black
Note 1 to entry: The envelopes of the 450 Hz signals are approximately rectangular.
4 Requirements
4.1 Construction
4.1.1 The equipment shall comprise of a radio receiver and a recording unit.
4.1.2 The recording unit shall be constructed as to allow for the change of recording paper and either
or both recording stylus during day and subdued artificial light. It should be possible to affect routine
maintenance under the same conditions.
4.2 Performance standards for recording unit
4.2.1 Recording unit
The equipment shall be capable of continuous recording while transmissions are being received.
4.2.2 Input signals
The recording unit shall accept input signals from an external receiver in the audio frequency range
at an input level of at least –10 dBm to +10 dBm and shifts of ±150 Hz and/or ±400 Hz about a centre
frequency of 1 900 Hz at an impedance of 600 Ω.
4.2.3 Index of cooperation (IOC)
Automatic or manual operation at an index of cooperation of 576 and 288 shall be possible.
4.2.4 Scanning speeds
The recording unit shall be capable of the automatic and manual selection of scanning speeds of 60, 90
and 120 scans per minute.
4.2.5 Automatic operation
The recording unit shall automatically respond to control signals of 300 Hz and 675 Hz modulation of the
carrier wave for start and index of cooperation selection shall be by detection of line synchronization
and to 450 Hz modulation stop signal.
4.2.6 Synchronization of scanning and phasing
The recording unit shall be capable of synchronization of its operation with the facsimile transmitter
by:
−6
— frequency accuracy of ±×210 min;
−5
— frequency stability of ±×210 min.
Phasing shall be automatic with a facility for manual adjustment.
4.2.7 Pitch of scanning trace
The pitch of scanning traces shall be maintained within ±25 % of its nominal value.
4.2.8 Recording size and marking
The minimum width of the recording shall be 180 mm.
The recording material shall be marked in such a way as to indicate that the material remaining is not
less than 1 m.
4.3 Performance standards for radio receiver
4.3.1 Receiving frequency
The radio receiver shall have a range within 110 kHz to 27 MHz of at least 3 MHz to 24 MHz with the
capability of receiving F3C transmissions. It should have up to six pre-set spot frequencies. Every
selected frequency shall be displayed or easily identified by an appropriate method.
4.3.2 Frequency stability
The frequency drift shall not exceed 50 Hz over the temperature range +15°C to +35 °C.
4.3.3 Sensitivity
Input to the receiver shall be 3 μV or less for 3 MHz and above, and 10 μV or less for 110 kHz up to 3 MHz
so that the recorder produces a readable picture.
4.3.4 Selectivity
Frequency bandwidth shall be within 6,2 kHz measured at the 6 dB attenuation points, and within
10 kHz at the 66 dB attenuation points.
4.3.5 Intermediate frequency rejection
Rejection of signals at the intermediate frequencies shall be greater than 60 dB.
4.3.6 Image frequency rejection
The receiver shall have an image frequency rejection of not less than 40 dB.
4.4 General requirement of the radio receiver and the recording unit
The radio rece
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