How do I obtain an Australian MMSI?
It is strongly recommended that you obtain a MMSI for your DSC radio.
Australian DSC MMSI's are issued by the Australian Maritime Safety
Authority (AMSA).
A copy of the on line application form may be found
here
(opens in new window - PDF: 80KB).
The AMSA MMSI registration database manager may also be contacted by
telephone on 1800 406 406 (Australia) or by email
here.
Australian MMSI list
(leave
the boxes on the search form blank and hit enter for the full list)
Users in other countries should contact their local Government Radio
Regulatory Agency/Department or Maritime Safety Authority.
What Australian qualifications do I need to use VHF DSC ?
As a minimum, you need a Marine Radio Operators VHF Certificate of
Proficiency (MROVCP), issued by The Australian Communications and Media
Authority (ACMA).
Many TAFEs and marine
organisations
offer courses leading to examination for the MROVCP. Persons
wishing to obtain the MROVCP should first purchase a copy of
the
Maritime Radio
Operator Handbook which is essential reading for
every boat owner in Australia.
The Australian Maritime College (AMC) provides the marine examination
and certificate service on behalf of the ACMA. The AMC can
provide the details of organisations and individuals offering
courses and or conducting exams.
For further information visit:
AMC marine radio info
VHF radios are covered by a class license. An individual
station license is no longer required. More information may
be found on the ACMA web site
here.
DSC
operational procedures
Formation of MMSI's
MMSI's
for merchant vessels are normally allocated with three
trailing
zero's.
Those
allocated to
recreational craft have two or one trailing
zero, Coast Station MMSI's are formed with two leading zero's and those
allocated to SAR aircraft use 111 as the first three digits.
For example:
Typical
Australian merchant vessel MMSI- 503001000
where:
503
is the Australian MID;
and
01000
is the individual ship number
Typical Australian recreational
vessel MMSI - 503000100
where:
503
is the Australian MID;
and
000100
is the individual ship number
Australian Coast Station MMSI
- 005030001
where:
503
is the Australian MID;
and
0001
is the individual Coast Station number
SAR aircraft MMSI - 111503123
where:
503
is the Australian MID;
and
123
is the individual aircraft number
The International
Telecommunications Union (ITU) operate an
international web-based data base of MMSI's, known as the Maritime
Mobile Access and Retrieval System (MARS).
DSC call types
The DSC system provides the following types of call;
Distress alert
- these calls are always addressed to ALL
stations. The call
contains the
distressed vessel's MMSI, her position, the nature of her distress and
the time
of the call.
DSC
controllers offer the user a menu of possible
"nature of distress" situations from which to choose, i.e.: -
"fire, explosion", "flooding", "collision",
"grounding" etc.
If the "nature of
distress" information is not
selected a controller will send the default setting of
"UNSPECIFIED".
The call will conclude with the advice that subsequent
communications are to be carried out on radiotelephone. The
channel for ongoing
communications on radiotelephone is
not specified in DSC distress messages, as it
is always the
radiotelephone distress channel – 16.
Distress
alert acknowledgment - normally sent by coast
stations in response to a distress alert from a ship.
Distress
alert relay - normally only sent by coast stations,
these calls are addressed to ALL stations.
All ship -
these broadcast messages can be sent as either
URGENT or SAFETY priority calls. The DSC controller will
prompt the user to select the
appropriate priority and the frequency or channel for subsequent
communications.
Single ship
(or station) - these calls can also be either
URGENT or SAFETY priority. They are addressed to a particular
ship or coast station.
The
MMSI of the required ship/station must be entered, as
well as the frequency for voice communications.
Routine
– the normal priority used to call
another ship or shore station.
Distress procedures
DSC equipment offers the user
the options of either sending a pre-programmed distress message by
operating a
single button or composing a message with the equipment.
All
DSC systems operate on a
'menu' arrangement, which allows the operator to choose from a fixed
selection
of distress scenarios.
A
distress call is normally activated only by means of a dedicated
distress button which is clearly
identified and protected against inadvertent operation by a
hinged flap.
Ship
in distress:
If time permits, an operator sending a VHF DSC distress message keys
in:
- nature of distress (defaults to
unspecified); and
- the ship's last known
position (latitude and longitude) and
time (in UTC) the position was valid (normally
inserted automatically
from GPS).
If time is short, simply lift the cover, press and hold down the red
DISTRESS button
After
the DSC message is sent, the operator then switches to
channel 16 and sends a voice MAYDAY message.
Action
by receiving ships and coast stations:
DSC
distress messages received
on VHF channel 70 are normally
acknowledged by radiotelephony on channel 16.
Acknowledgment of a DSC distress
alert by the use of a DSC acknowledgment message is normally made by
coast
stations only.
A ship receiving a distress
alert on channel 70 should immediately listen on channel 16
for the voice
MAYDAY message from the ship in distress.
Ships
receiving a DSC distress
alert from another ship should normally defer the acknowledgment of the
distress alert for a short interval, if the ship is within an area
covered by
one or more coast stations, in order to give the coast station time to
acknowledge the DSC distress alert first.
A vessel in range will be
alerted by the DSC message, copy the voice Mayday on channel 16, send a
voice
acknowledgment message, and conduct ongoing voice traffic with the
vessel in
distress.
A
DSC acknowledgment message
should only be sent on VHF DSC from a ship if attempts to contact the
vessel in
distress via radiotelephone on channel 16 have failed, and the vessel
in
distress continues to send DSC distress alerts on channel 70.
DSC Urgency/Safety procedures
Transmission
of urgency and/or
safety messages are carried out in two steps:
- Announcement of the message
using DSC, and
- Transmission of the message
using voice.
Urgency priority voice messages are normally
transmitted on channel 16.
Safety
priority voice messages are normally transmitted on a working channel
such as 67
or 69.
The
DSC call may be addressed
to all stations or to a specific station.
The
channel on which the Urgency or Safety voice message will be
transmitted is included in the DSC call (i.e.:
all DSC calls, apart from distress require the nomination of an
associated
voice working channel).
Ships receiving an urgency or
safety priority DSC message do NOT acknowledge receipt via DSC, but
tune their VHF
transceiver to the channel nominated in the DSC message, and await the
voice
urgency or safety message.
The
complete ITU DSC operational procedures guide may be found here.
Flow
chart - Actions on receipt of a VHF DSC call
DSC technical specs
