The reception of Maritime Safety Information (MSI ) is one of the nine functional requirements of GMDSS Equipment . The Navtex Receiver is used for this purpose it is a NBDP device operating on the frequency 518 KHZ and automatically receives
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Friday 24 October 2014
Wednesday 22 October 2014
DIGITAL SELECTIVE CALLING ( DSC )
The DSC ststem employs digital technology and is an important part of the GMDSS System, being used as the primary means of VHF / MF / HF alerting.
DSC is used for calls in the ship to ship , ship to shore and shore to ship directions for distress and routine purposes .
Note ; it is a calling system and not a working system.
In a distress situation, the DSC distress call contains at least the distress vessels MMSI no and position with its time of update.
DSC is used for distress and safety as well as routine communications.
A typical DSC calling sequence consists of ;
Once the ITU Channel number is entered in the transceiver , it automatically sets the frequency of the Transmitter and Receiver Frequencies can also separately by using the Tx and Rx controls.
Mode is a Transmitter and Receiver Control ;-
J3E also termed SSB , USB
H3E also termed AM
F1B / J2B also termed TLX
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would you like to read about ;-
GMDSS
ALRS
INMARSAT
IAMSAR
.
DSC is used for calls in the ship to ship , ship to shore and shore to ship directions for distress and routine purposes .
Note ; it is a calling system and not a working system.
In a distress situation, the DSC distress call contains at least the distress vessels MMSI no and position with its time of update.
DSC is used for distress and safety as well as routine communications.
A typical DSC calling sequence consists of ;
- Format specifier - specifies the type of call , ie Distress / all ships / selective
- Address - is used to specify which station is to receive the call , ie all ships / selective / individual
- Category - call priority , ie Distress / Urgency / Safety / Routine
- Self Identification - own ships MMSI
- Telecommand Information
- Frequency Information- frequency / channel
- End of sequence- to indicate whether this call requires Ack or is Reply to a call
VHF DSC
Once the ITU Channel number is entered in the transceiver , it automatically sets the frequency of the Transmitter and Receiver Frequencies can also separately by using the Tx and Rx controls.
Mode is a Transmitter and Receiver Control ;-
J3E also termed SSB , USB
H3E also termed AM
F1B / J2B also termed TLX
- Squelch is a receiver control , used to eliminate noise.
- Tune is a Transmitter Control
- Power is a Transmitter Control
- Dummy Load is a Transmitter Function
- Frequency Selection in a Transmitter & Receiver Control
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would you like to read about ;-
GMDSS
ALRS
INMARSAT
IAMSAR
.
IAMSAR - International Aeronautical and Maritime and Rescue
Under long standing traditions of sea anf various provisions of international law, ship masters are obliged to assist others in distress at sea whenever they can safely do so. the resposibilities to render assistance to a distressed vessel or aircraft are based on humanitarian considerations and established international practice.
Many states have accepted the obligation to provide aeronautical and maritime SAR (search and rescue) co ordination and services on a 24 hour basis for their territories, territorial seas and where appropriate the high seas. to carry out these responsibilities , all ocean area are divided into Search and Rescue Regions (SRR ) and national or regional SAR organisation established.
The SAR Co-ordination system has 3 general levels :-
One of the basic concepts involves ships being able to alert Maritime Rescue Co ordination Centre (MRCC ) ashore as well as ships in the Vicinity of the distressed vessel.
The GMDSS takes advantage of modern automated technology in both satellite and terrestrial communication to establish contact with MRCC.
In addition each MRCC is equipped with communication links with :-
Master Plan for the GMDSS :-
Information provided by the governments on shore based facilities for satellites and terrestrial communications services for the GMDSS is included in the master plan for GMDSS in annex of the IMO - GMDSS HANDBOOK.
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Many states have accepted the obligation to provide aeronautical and maritime SAR (search and rescue) co ordination and services on a 24 hour basis for their territories, territorial seas and where appropriate the high seas. to carry out these responsibilities , all ocean area are divided into Search and Rescue Regions (SRR ) and national or regional SAR organisation established.
The SAR Co-ordination system has 3 general levels :-
- SAR Coordinator (SC )
- SAR Mission Coordinator (SMC)
- On scene Coordinators (OSC )
- SC :- Scs have the overall responsibility of establishing and managing the SAR system, establishing RSC & RCC . providing SAR facilities .coordination SAR training and developing SAR policies.
- SMC :- Each SAR operation is carried out under the guidance of an SMC, by the RCC Chief or a designee. for this the SMC should be well trained in all SAR processes and familiar with the applicable SAR plans.
- OSC :- When two or more SAR facilities are working together on the same mission, a person on scene may be needed to co ordinate the activities of the participating facilities. the SMC designates an OSC which may be a participating SAR unit or nearby facility which can handle OSC duties.
One of the basic concepts involves ships being able to alert Maritime Rescue Co ordination Centre (MRCC ) ashore as well as ships in the Vicinity of the distressed vessel.
The GMDSS takes advantage of modern automated technology in both satellite and terrestrial communication to establish contact with MRCC.
In addition each MRCC is equipped with communication links with :-
- The associated LES ( land Earth Station )
- CRS ( Coast radio station )
- COSPAS SARSAT MCC ( Mission Control center )
Master Plan for the GMDSS :-
Information provided by the governments on shore based facilities for satellites and terrestrial communications services for the GMDSS is included in the master plan for GMDSS in annex of the IMO - GMDSS HANDBOOK.
- status of shore based facilities for the GMDSS
- List of VHF / MF / HF DSC Coast stations for AREA A1 / A2 / A3 /A4
- List of Inmarsat Coast Earth Stations
- List of RCC
- NAVTEX
- HF NBDP MSI broadcast service
- List of COSPAS SARSAT MCC and LUT
- Satellite EPIRB registration information
- List of 24 hour points of contract for MMSI
Click on below link for more updated information :-
Would like to know about :-
Distress Communication by INMARSAT
Always Ask : Which Inmarsat type ?? B or C or F
Also Ask : Which Mode ? Telex or Telephone
Remember : Selection of Distress priority on the SES inmarsat terminal causes the transmission of information that follows to be directly received by a MRCC ( Maritime Rescue Corordination Center ) ashore and not to all stations / Ships.
Distress procedure on Inmarsat B
Telex Voice
Also Ask : Which Mode ? Telex or Telephone
Remember : Selection of Distress priority on the SES inmarsat terminal causes the transmission of information that follows to be directly received by a MRCC ( Maritime Rescue Corordination Center ) ashore and not to all stations / Ships.
Distress procedure on Inmarsat B
Telex Voice
- Select Telex on line Select Telephone mode
- Press and hold Distress button 6 sec Press and hold Distress button 6 sec
- After MRCC comes on line:- Initiate call
B. Send typed out Distress message manually
Distress procedure on Inmarsat C
To send an Undesignated Distress alert : - press Distress button
To send a Designated Distress alert :- update info in distress menu then press distress button.
Note :- Both types of Distress alerts can be sent even if the terminal is not logged in .
To send Distress message to MRCC :-
- Prepare the message ( in the terminal editor )
- Select Distress Priority (in the transmit menu )
- Transmit the message using the same LES (Land earth Station ) , through which the alert was sent
ADMIRALTY LIST OF RADIO SIGNALS (ALRS ) , VOLUME 1,2,3,4,5,6
This series of books is published by the Hydrographer of the Royal Navy, they provide details of service provided by Shore Radio Stations and general reference sections describing many maritime radio related services.
Regular updates are issued through weekly Notices to Mariners.
Volume 1 (NP 281 - 1 & 2 ) : Coast Radio Stations contains details of Shore Stations services , IDs, frequencies , classesof emission, details on the use of INMARSAT. Ship Reporting systems like AMVER , Pollution and Piracy reporting procedures, info about Radio Medical advise, Radio quarantine reports.
Part 1 - Europe , Africa and Asia ( excluding the far east )
Part 2 - Oceania, the America and the far east
Volume 2 ( NP282 ) : Radio Navigational aids
Radio Direction finding stations, Radar Beacon services , Satellites Navigation systems, DGPS correction beacons , Radio Time Signals and related info, Electronic position fixing system details with diagrams.
Volume 3 (NP 283 1& 2) : Maritime Safety Information (MSI ) Services. Radio weather and Nav warning services , Navtex references, with related diagrams.
Part 1 - Europe , Africa and Asia
Part 2 - Oceania and the Americas
Volume 4 (NP 284) : List of Meterological Observation Stations.
Volume 5 (NP 285 ) : Global Maritime Distress and Safety System (GMDSS )
Volume 6 (NP 286 ) : Pilot services, vessels Traffic Services and Port operations. detailed Pilot Information and Vessel traffic services with associated diagrams, harbour VHF facilities.
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would you like to know
GMDSS ( Global Maritime Distress & Safety System )
IAMSAR
INMARSAT
.
.
Regular updates are issued through weekly Notices to Mariners.
Volume 1 (NP 281 - 1 & 2 ) : Coast Radio Stations contains details of Shore Stations services , IDs, frequencies , classesof emission, details on the use of INMARSAT. Ship Reporting systems like AMVER , Pollution and Piracy reporting procedures, info about Radio Medical advise, Radio quarantine reports.
Part 1 - Europe , Africa and Asia ( excluding the far east )
Part 2 - Oceania, the America and the far east
Volume 2 ( NP282 ) : Radio Navigational aids
Radio Direction finding stations, Radar Beacon services , Satellites Navigation systems, DGPS correction beacons , Radio Time Signals and related info, Electronic position fixing system details with diagrams.
Volume 3 (NP 283 1& 2) : Maritime Safety Information (MSI ) Services. Radio weather and Nav warning services , Navtex references, with related diagrams.
Part 1 - Europe , Africa and Asia
Part 2 - Oceania and the Americas
Volume 4 (NP 284) : List of Meterological Observation Stations.
Volume 5 (NP 285 ) : Global Maritime Distress and Safety System (GMDSS )
Volume 6 (NP 286 ) : Pilot services, vessels Traffic Services and Port operations. detailed Pilot Information and Vessel traffic services with associated diagrams, harbour VHF facilities.
Click on below link for more updated information :-
......................................................................>>>>
would you like to know
GMDSS ( Global Maritime Distress & Safety System )
IAMSAR
INMARSAT
.
.
what is GMDSS - Global Maritime Distress & Safety Systems introduction
Full implementation of GMDSS regulations was effected on 1 Feb 1999 , applying to all cargo ships 300 Gross tons & above & to all Passenger Ships, Regardless of size on International Voyages.
Before GMDSS was implemented, a radio watch was kept on the Distress Frequencies by a dedicated Ofiicer using Headphones or Loudspeakers.
In the GMDSS, the DSC - Digital Selective Calling Equipment keeps Watch automatically.
Before GMDSS , a vessel in Distress relied primarily on another vessel for assistance.
The GMDSS emphasizes the ability to alert SAR - Search & Rescue , authorities ashore as well as shipping in the to achieve a co-ordinated response to Distress situations.
GMDSS involves Terrestrial as well as Satellite Communications System.
DSC is a terrestrial system available in the MF / HF / VHF frequency bands.
Characteristics of the Earth / Sea / like Terrain / Surface, Weather Conditions, day night times affect the Propogation of these signals.
Shore stations used in terrestrial communications are called CRS - Coast Radio Stations.
Note- not all CRS are equipped with DSC facilities.
Satellite communications in the GMDSS involves the INMARSAT - Inmarsat Satellites systems for Distress & Routine communications and the COSPAS SARSAT systems for distress purposes only.
Shore stations in the INNARSAT systems are known as LES - Land Earth Stations.
Shore Stations in the COSPAS SARSAT system are called LUT - Local User Terminal .
DSC is a calling system, not a working system - it is a means of establishing contact , requiring receiving stations to watch on an appropriate frequency to receive the rest of the information sent by non DCS means on non DSC frequencies.
The DSC Equipments has the MMSI - Maritime Mobile Service Identity number of the vessel programmed into itself, it is also interfaced with the GPS onboard , which means that the DSC equipment knows who its is and where it is
This makes it possible to use DSC to automatically address information, attract the attention of all stations , an individual station , a group of ships, within A Defined Geographical Area .
GMDSS Sea Areas ;-
A1 - area within the Radiotelephone coverage of at least one VHF Coast station in which continuous DSC alerting is available. Such an area could extend about 20- 50 Miles Offshore.
A2 - Area , excluding Sea area A1, within the Radiotelephone coverage of at least one MF Coast Station in which Continuous DSC alerting is available. Such an area could extent about 150 - 250 Miles Offshore.
A3 - Area excluding Sea area A1 & A2 , within coverage of Inmarsat Geo-stationary Satellite in which continuous alerting is available. area lies between about Latitudes 70 Degree North & South.
A4 - Area outside Sea Areas A1, A2, A3 ( Polar Regions )
.................................................................>>>>
would you like to know about :-
ALRS ( Admiralty List of Radio Signals )
IAMSAR
INMARSAT
.
Before GMDSS was implemented, a radio watch was kept on the Distress Frequencies by a dedicated Ofiicer using Headphones or Loudspeakers.
In the GMDSS, the DSC - Digital Selective Calling Equipment keeps Watch automatically.
Before GMDSS , a vessel in Distress relied primarily on another vessel for assistance.
The GMDSS emphasizes the ability to alert SAR - Search & Rescue , authorities ashore as well as shipping in the to achieve a co-ordinated response to Distress situations.
GMDSS involves Terrestrial as well as Satellite Communications System.
DSC is a terrestrial system available in the MF / HF / VHF frequency bands.
Characteristics of the Earth / Sea / like Terrain / Surface, Weather Conditions, day night times affect the Propogation of these signals.
Shore stations used in terrestrial communications are called CRS - Coast Radio Stations.
Note- not all CRS are equipped with DSC facilities.
Satellite communications in the GMDSS involves the INMARSAT - Inmarsat Satellites systems for Distress & Routine communications and the COSPAS SARSAT systems for distress purposes only.
Shore stations in the INNARSAT systems are known as LES - Land Earth Stations.
Shore Stations in the COSPAS SARSAT system are called LUT - Local User Terminal .
DSC is a calling system, not a working system - it is a means of establishing contact , requiring receiving stations to watch on an appropriate frequency to receive the rest of the information sent by non DCS means on non DSC frequencies.
The DSC Equipments has the MMSI - Maritime Mobile Service Identity number of the vessel programmed into itself, it is also interfaced with the GPS onboard , which means that the DSC equipment knows who its is and where it is
This makes it possible to use DSC to automatically address information, attract the attention of all stations , an individual station , a group of ships, within A Defined Geographical Area .
GMDSS Sea Areas ;-
A1 - area within the Radiotelephone coverage of at least one VHF Coast station in which continuous DSC alerting is available. Such an area could extend about 20- 50 Miles Offshore.
A2 - Area , excluding Sea area A1, within the Radiotelephone coverage of at least one MF Coast Station in which Continuous DSC alerting is available. Such an area could extent about 150 - 250 Miles Offshore.
A3 - Area excluding Sea area A1 & A2 , within coverage of Inmarsat Geo-stationary Satellite in which continuous alerting is available. area lies between about Latitudes 70 Degree North & South.
A4 - Area outside Sea Areas A1, A2, A3 ( Polar Regions )
Click on below link for more updated information :-
.................................................................>>>>
would you like to know about :-
ALRS ( Admiralty List of Radio Signals )
IAMSAR
INMARSAT
.
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