Part A General
1 INTRODUCTION
The MF radiotelephone
and digital selective calling installation, in addition to meeting the requirements
of the Radio Regulations, should comply with the following performance standards and
with the general requirements set out in Assembly resolution A.569(14).
2 GENERAL
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 and two-frequency channels.
2.2
The equipment should provide for the following categories of calling using both
voice and digital selective calling (DSC):
.1 distress,
urgency and safety;
.2 ship operational requirements; and
.3 public correspondence.
2.3 The equipment should provide for the following categories
of communications using voice and, optionally, narrow-band direct printing (NBDP):
.1 distress, urgency and safety;
.2 ship operational requirements; and
.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 units;
.3 a microphone with a
press-to-transmit switch which may be combined with a telephone in a handset;
.4 an internal or external loudspeaker;
.5 an integral or separate digital selective calling facility; and
.6 a dedicated DSC watch keeping facility to maintain a
continuous watch on the distress channel.
2.5
Power supply
The MF radio installation should be powered from the ship's main
source of electrical energy. In addition, it should be possible to operate the MF
installation from an alternative source of electrical energy.
2.6 Control
It should be possible to conduct distress and safety
communications from the position, or in the vicinity of the position, from which the
vessel is normally navigated.
Part B Transmitters
1 Frequencies and classes of emission
1.1 The radiotelephone and DSC transmitter should be
capable of transmitting on a number of frequencies in the bands between 1,605 kHz
and 4,000 kHz considered by the Administration as adequate for the operation of
the ship, but at least on the frequencies 2,182 kHz and 2,187.5 kHz.
1.2 Radiotelephone frequencies are
designated in terms of the carrier frequency; DSC frequencies are designated in
terms of the assigned (centre) frequency. When DSC signals are transmitted using a
transmitter in J2B mode the (suppressed) carrier frequency should be adjusted so
as to have the DSC signal transmitted on the assigned DSC frequency. The selected
transmitter frequency should be clearly identifiable on the control panel of the
equipment.
1.3 .1 The transmitter
should be capable of transmitting (upper side band signals, where appropriate)
using classes of emission J3E, H3E and either J2B or F1B.
.2 When switching to the preset distress frequency 2,182 kHz the
appropriate class of emission in accordance with the Radio Regulations should be
selected automatically. *
.3 When switching to the preset
distress frequency 2,187. 5 kHz the class of emission J2B or F1B should be
selected automatically. *
1.4 It should
be possible to change the transmitter from any class of emission to another for
which it is designed to operate by means of not more than one control.
1.5 It should be possible for the user to
select transmission frequencies independent of any receiver setting. This does not
preclude the use of transceivers.
1.6
It should be possible to change the transmitter quickly from operation on any
frequency to operation on any other frequency, and in any event within a period
not exceeding 15 s. The equipment should not be able to transmit during channel
switching operations.
1.7 Means should
be provided to prevent overmodulation automatically.
* Existing transmitters during the transition and amortization period may be
exempted from these requirements. 2 Frequency stability and accuracy
The transmitter frequency should remain within 10.of the
required frequency at all times following the warming-up period.
3 Output power*
3.1 During normal modulation, the peak envelope power
in the case of J3E or H3E emissions, or the mean power in the case of J2B or F1B
emissions, should be at least 60 W at any frequency within the specified frequency
range.
3.2 If the rated output power
exceeds 400 W, provision should be made for reducing the output to 400 W or less.
* In determining the A2 area an antenna efficiency of 25% and an output power
of 60 W are assumed. 4 Permissible warming-up period
The equipment should be capable of operating on 2,182 kHz
and 2,187.5 kHz within 1 min after switching on.
5 Continuous operation
Continuous operation should be possible when the transmitter
is adjusted to its rated power.
6 Controls and indicators
6.1 Provision should be made for indicating the
antenna current or power delivered to the antenna. Failure of the indicating
system should not interrupt the antenna circuit.
6.2 Manually tuned equipment should be fitted with a
sufficient number of indicators to permit accurate and rapid tuning.
6.3 Operation of the transmit/receive
control should not cause unwanted emissions.
6.4 All adjustments and controls necessary for switching the
transmitter to operate on 2,182 kHz and 2,187.5 kHz should be clearly marked in
order that these operations may be performed readily.
7 Safety precautions
The equipment should be so designed and constructed that
when the transmitter is providing power to the antenna the transmitter is
protected against damage resulting from disconnection of the antenna or
short-circuiting of antenna terminals. If this protection is provided by means of
a safety device, that device should automatically be reset following removal of
the antenna open-circuit or short-circuit conditions.
8 Power supply
8.1 If it is necessary to delay the application of
voltage, for example anode voltage, to any part of the transmitter after switching
on, this delay should be provided automatically.
8.2 If
the transmitter includes parts which are required to be heated in order to operate
correctly, for example crystal ovens, the power supplies to the heating circuits
should be so arranged that they can remain operative when other supplies to or
within the equipment are switched off. If a special switch for the heating
circuits is provided, its function should be clearly indicated; it shall normally
be in the "on" position and be protected against inadvertent operation. The
correct operating temperature should be reached within a period of 30 min after
the application of power.
Part C Receivers
1 Frequencies and classes of emission
1.1 The receiver should be capable of being tuned
throughout the bands between 1,605 kHz and 4,000 kHz. Tuning should be either
continuous, or by incremental steps, or by the selection of a number of spot
frequencies considered by the Administration as adequate for the operation of the
ship, or by any combination of these methods. The frequencies 2,182 kHz and
2,187.5 kHz should always be included.
1.2 Radiotelephone frequencies should be designated in terms of the
carrier frequency; DSC frequencies should be designated in terms of assigned
(centre) frequency. The selected receiver frequency should be clearly identifiable
on the control panel of the equipment.
1.3 The receiver should be capable of receiving upper side band signals
as appropriate for classes of emission J3E, H3E, J2B and F1B.
1.4 The class of emission should be selectable by not
more than one control.
1.5 It should be
possible for the user to select reception frequencies independent of any
transmitter setting. This does not preclude the use of transceivers.
1.6 The receiver should be capable of
being tuned to different frequencies quickly, and in any event within a period not
exceeding 15 s.
2 Frequency stability and accuracy
The receiver frequency should at all times remain within 10
Hz of the required frequency following the warming-up period.
3 Usable sensitivity
For classes of emission J3E and F1B the sensitivity of the
receiver should be equal to or better than 6 μV e.m.f. at the receiver input for a
signal-to-noise ratio of 20dB. For DSC an output character error rate of 10
-2 or less should be obtained for a signal-to-noise ratio of 12dB.
4 Receiver output
4.1 For the reception of voice signals, the receiver
should be suitable for use with a loudspeaker and a telephone handset and should
be capable of providing power of at least 2 W to the loudspeaker and at least 1mW
to the handset.
4.2 An output should be
provided for DSC signals if the corresponding facility is not integrated .
5 Permissible warming-up period
The equipment should be capable of operating on 2,182 kHz
and 2,187.5 kHz within 1 min after switching on.
6 Immunity to interference
The immunity to interference of the receiver should be such
that the wanted signal is not seriously affected by unwanted signals.
7 Controls
7.1 All adjustment and controls necessary for
switching the receiver to operate on 2,187.5 kHz should be clearly marked in order
that these operations may be performed readily. The arrangements for switching the
receiver to operate on 2,182 kHz should also be clearly marked.
7.2 The receiver should be provided with automatic
gain control.
8 Power supply
If the receiver includes parts which are required to be
heated in order to operate correctly, for example crystal ovens, the power
supplies to the heating circuits should be so arranged that they can remain
operative when other supplies to or within the equipment are switched off. If a
special switch for the heating circuits is provided, its function should be
clearly indicated; it shall normally be in the "on" position and be protected
against inadvertent operation. The correct operating temperature should be reached
within a period of 30 min after the application of power.
Part D Digital selective calling facility
1 The facility should conform to the provisions of the
relevant CCIR Recommendations pertaining to the DSC system. *
2 The DSC facility should comprise:
.1 means to decode and encode DSC messages;
.2
means necessary for composing the DSC message;
.3 means to
verify the prepared message before it is transmitted;
.4
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
.6 means
for the manual entry of the time at which the position was determined; additionally
automatic entry may be provided.
3
DISTRESS MESSAGE STORAGE
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.
3.2 These messages should be
stored until read-out.
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.
5 Initiation of DSC distress calls should supersede any other
operation of the facility.
6
Self-identification data should be stored in the DSC unit. It should not be possible
for the user easily to change these data.
7 Means should be provided to enable routine testing of the DSC
facilities without radiation of signals.
8 Provision should be made for 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 manually.
* Class A or B DSC equipment conforming to CCIR Recommendation 493 should be used
to meet this requirement.