Article 15(j) of the Convention on the International Maritime Organization concerning
the functions of the Assembly in relation to regulations and guidelines concerning
RECOGNIZING the need to prepare
performance standards for VHF radio installations capable of voice communication and
digital selective calling to be used in the global maritime distress and safety system
(GMDSS) in order to ensure the operational reliability of such equipment and to avoid,
as far as practicable, adverse interaction between such equipment and other
communication and navigation equipment aboard ship.
HAVING CONSIDERED the recommendation made by the Maritime Safety Committee at its
1. ADOPTS the Recommendation on
Performance Standards for Shipbone VHF Radio Installations Capable of Voice
Communication and Digital Selective Calling, the text of which is set out in the Annex
to this resolution;
2. RECOMMENDS Member Governments
to ensure the shipborne VHF radio installations capable of voice communication and
digital selective calling which will form part of the global maritime distress and
safety system (GMDSS) conform to performance standards not inferior to those specified
in the Annex to this resolution.
Annex Recommendation on performance standards for shipborne VHF radio installations capable of voice communication and digital selective calling
The VHF radio installation, in addition to meeting the
requirements of the Radio Regulations, the relevant CCIR Recommendations and the
general requirements set out in resolution A.569(14), should comply with the
following performance standards.
2.1 The installation, which may consist of more than
one piece of equipment, should be capable of operating on single-frequency channels
or on single- or two- frequency channels.
2.2 The equipment should provide for the following categories of calls
using both voice and digital selective calling (DSC):
distress, urgency and safety;
.2 ship operational
.3 public correspondence.
2.3 The equipment should provide for the
following categories of communications using voice:
distress, urgency and safety;
.2 ship operational
.3 public correspondence.
2.4 The equipment should comprise at least:
.1 a transmitter/receiver including antenna;
.2 an integral control unit or one or more separate control
.3 a microphone with a press-to-transmit switch,
which may be combined with a telephone in a handset;
internal or external loudspeaker;
.5 an integral or
separate digital selective calling facility; and
dedicated DSC watchkeeping facility to maintain a continuous watch on channel 70.
2.5 The installation may also include
03 Class of emission, frequency bands and channels
3.1 The equipment may be designated for operation on
one or more channels selected from and in accordance with appendix 18 of the Radio
3.2 The radiotelephone
facility shall be capable of operating as follows:
the band 156.3 MHz to 156.875 MHz on single-frequency channels as specified in
appendix 18 to the Radio Regulations; and
.2 in the band
156.025 MHz to 157.425 MHz for transmitting and the band 160.625 MHz to 162.025 MHz
for receiving on two-frequency channels as specified in appendix 18 to the Radio
3.3 The digital selective
calling facility should be capable of operating on channel 70.
3.4 Class of emission should comply with appendix 19 of the
04 Controls and indicators
4.1.1 Change of channel should be capable
of being made as rapidly as possible, but in any event within 5 s.
4.1.2 The time taken to switch from the transmit to the
receive condition, and vice versa, should not exceed 0.3 s.
4.1.3 An on/off switch should be provided for the entire
installation with a visual indication that the installation is switched on.
4.1.4 A visual indication that the carrier
is being transmitted should be provided.
4.1.5 The equipment should indicate the channel number, as given in the
Radio Regulations, to which it is tuned. It should allow the determination of the
channel number under all conditions of external lighting. Where practicable,
channels 16 and 70 should be distinctively marked.
4.1.6 Control of the equipment should be possible at the
position from which the ship is normally navigated. Control from that position
should have priority if additional control units are provided. When there is more
than one control unit, indication should be given to the other units that the
equipment is in operation.
equipment should not be able to transmit during channel switching operation.
4.1.8 Operation of the transmit/receive
control should not cause unwanted emissions.
4.2 Radiotelephone facility
4.2.1 Provision should be made for
changing from transmission to reception by use of a press-to-transmit switch.
Additionally, facilities for operation on two-frequency channels without manual
control may be provided.
receiver should be provided with a manual volume control by which the audio output
may be varied.
4.2.3 A squelch control
should be provided on the exterior of the equipment.
05 Permissible warming-up period
The equipment should be operational within 1 min of switching
06 Safety precautions
The equipment, when operating, should not be damaged by the
effects of open-circuited or short-circuited antenna terminals .
07 Transmitter output power
7.1 The transmitter output power should be between 6
and 25 W.
7.2 Provision should be made
for reducing the transmitter output power to a value of between 0.1 and 1 W.
However, this reduction of the power is optional on channel 70.
08 Receiver parameters
8.1 Radiotelephone facility
sensitivity of the receiver should be equal to or better than 2 μV e.m.f. for a
signal-to-noise ratio of 20 dB.
Digital selective calling facility
With a DSC modulated input
signal having a level of 1 μV e.m.f. to its associated VHF receiver, the DSC
equipment should be capable of decoding the received message with a maximum
permissible output character error rate of 10 -2.
8.3 Immunity to interference
to interference of the receiver should be such that the wanted signal is not
seriously affected by unwanted signals.
09 Antenna system
The VHF antenna or antennae should be vertically polarized
and, as far as practicable, be omnidirectional in the horizontal plane. The
installation should be suitable for efficient radiation and reception of signals at
the operating frequencies.
10 Loudspeaker and telephone handset (radiotelephone facility)
10.1 The receiver output should be suitable for use
with a loudspeaker or a telephone handset. The audio output should be sufficient to
be heard in the ambient noise level likely to be encountered on board ships.
10.2 It should be possible to switch off
the loudspeaker without affecting the audio output of the telephone handset, if
10.3 In the transmit condition
during simplex operation, the output of the receiver should be muted.
10.4 In the transmit condition during
duplex operation, only the telephone handset should be in circuit. Care should be
taken to prevent any electrical or acoustic feedback, which could cause
11 Digital selective calling facility
11.1 The facility should conform to the provisions of
the relevant CCIR Recommendations pertaining to the DSC system.*
11.2 The DSC facility should comprise:
.1 means to decode and encode DSC messages;
means necessary for composing the DSC message;
.3 means to
verify the prepared message before it is transmitted;
means to display the information contained in a received call in plain language;
.5 means for the manual entry of the position information;
additionally, automatic entry may be provided; and
for the manual entry of the time at which the position was determined; additionally,
automatic entry may be provided.
Distress message storage
11.3.1 If the received messages are not
printed immediately, sufficient capacity should be provided to enable at least 20
received distress messages to be stored in the DSC facility.
11.3.2 These messages should be stored until readout.
11.4 It should be possible to initiate and
make distress and safety calls from the position from which the ship is normally
navigated. The means for initiating a distress call should be easy to operate and
protected against inadvertent activation.
11.5 Initiation of DSC distress calls should supersede any other
operation of the facility.
Self-identification data should be stored in the DSC unit. It should not be possible
for the user easily to change these data.
11.7 Means should be provided to enable routine testing of the DSC
facilities without radiation of signals.
11.8 Provision should be made for:
.1 a specific
aural alarm and visual indication to indicate receipt of a distress or urgency call
or a call having distress category. It should not be possible to disable this alarm
and indication. Provision should be made to ensure that they can be reset only
.2 aural alarms and visual indication for
calls other than distress and urgency.
* Class A or B DSC equipment conforming to CCIR Recommendation 493 should be used
to meet this requirement.
12 Power supply
The VHF radio installation should be powered from the ship's
main source of electrical energy. In addition, it should be possible to operate the
VHF installation from an alternative source of electrical energy.