GMDS - COURSE - FINAL.doc

7/26/2019 GMDS - COURSE - FINAL.doc

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Model course 1.25

GENERAL OPERATORSCERTIFICATE FOR THE

GLOBAL MARITIME

DISTRESS

AND SAFETY SYSTEM

2015 EDITION

Course + Compendium

electronic edition


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Print edition (ISBN First978-92published-801-1611in-3)1997rstb!publishedthe in1997 b! the


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Introduction to the Compendium

This Compendium to the IMO model course for the GMDSS GOC is intended as an aid toboth students and instructors. It aims to bring together, into one document, theoryconcerning dierent aspects of radio communications, hich may be of !alue in the

e"planation and comprehension of sub#ects studied for the GOC.The instructor may use the document as radio communications theory reference or$, tosupplement the documents listed in %art & of the IMO model course. 'hen using theCompendium, it should be noted that the students are training to become operators ofradio communications e(uipment and not technicians or engineers )although that can bemore or less accomplished by doing the *rst+ or second+class adio -lectronic Certi*cate.Students may *nd the theoretical and general interest parts helpful as bac$groundreading, hich ill increase and clarify their understanding of the sub#ects.

It should be noted that the material co!ered by the Compendium is, in places, in e"cess ofthat re(uired by the holder of a GMDSS GOC Certi*cate.

1 Introductionadio has been the foundation of the distress and safety systems used ship sea instance ofthe use ofradio to sa!e li!es at sea as in /011. It as soon reali2ed that, eecti!e, radio+baseddistress and safetysystem had to be founded rules concerning type of e(uipment, the radio fre(uencies usedand operationalinternational agreement as established under the auspices of the predecessor to the"nion )IT3. Many ofthe operational procedures for morse telegraphy ha!e been maintained to the present day.#$riti%e /100The current system is called the S$&et! S!ste% )GMDSS.This system as adopted by the

Intern$tion$land replaces the 455 $62 Morse code system. The GMDSS pro!ides a reliable path inaddition to ship+to+ship alerting communications. The ne system is to+shore and ship+to+ship alerting bymeans of terrestrialradio and satellite radio paths for alerting and subse(uent communications. The GMDSSill apply to all cargo ships of 755 gross tonnages and abo!e, and to all passenger ships,regardless of si2e, on international !oyages.

2 Statutory framework of the Maritime Mobile Service

Figure 1 St$tutor! &r$%e'or


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General Operator8s Certi*cate for the GMDSS

International Convention of Safety of Life at Sea

Figure 2 S*+S

&s more detailed regulations became necessary for the shipping industry, the most recent ofthe International Con!ention for the S$&et! o& *i&e $t Se$)SO9&S /1:; as adopted in /1:;,

/1:0 and /100 and amended from time to time. The SO9&S Con!ention has become one of themain instruments of the IMO. The GMDSS

used by most of the orld8s shipping until /11< is de*ned by Chapter I= of the SO9&Sention and theIT3 ,$dio ,e-ul$tions). There as a transition period from the old to the ne order toallo theindustry time to o!ercome any unforeseen problems in implementation of system. Thetransitional periodbegan on / >ebruary /11< and continued to / >ebruary /111.SO9&S Chapter I= applies to all ships engaged e"cept?

@@ Cargo ships less than 755 gross

@@ Ships of ar and troopships,

@@ Ships not propelled by mechanical

@@ 'ooden ships of primiti!e

@@ %leasure yachts not

engaged @@ >ishing !essels,

and

@@ Ships being na!igated ithin the Great 9a$es of Aorth &merica.

Functional requirements

The GMDSS is a largely, but not fully, automated system hich re(uires ships to ha!e arange of e(uipment capable of performing the nine radio communication functions of theGMDSS in accordance ith egulation ;+/ of the SO9&S Con!ention. -!ery ship, hile atsea, shall be capable for the?

@@ transmission of ship+to+shore distress alerts by at least to separate andindependent means, each using a dierent radio communication ser!iceB

@@ reception of shore+to+ship distress alertsB

@@ transmission and reception of ship+to+ship distress alertsB

@@ transmission and reception of search and rescue coordinating

communicationsB @@ transmission and reception of on+scene

communicationsB

@@ transmission and reception of signals for locatingB

@@ transmission and reception of maritime safety informationB

@@ transmission and reception of general radio communications to and from shore+based radio systems or netor$sB and

@@ transmission and reception of bridge+to+bridge communications.


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40 MOD-9 CO3S- /.


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.o%pendiu%

Sea Areas

2.1.2. Sea Areas

2.1.2.1.Definitions of coverage and sea areas for Digital Selective Calling DSC!

"he #$DSS is based on the concept of using four marine communication sea areasto determine the operational% maintenance and personnel re&uirements for maritimeradio communications.

Sea area A1 means an area within the radiotelephone coverage of at least

one '() coast station in which continuous DSC alerting is available% as may

be defined by a Contracting #overnment. Such an area could e*tend typically

about +, nautical miles nm! from the coast station S/S Chapter 0'%eg.

2-12!.

Sea area A2 means an area% e*cluding sea area /1% within the radiotelephone

coverage of at least one $) coast station in which continuous DSC alerting is

available% as may be defined by a Contracting #overnment. )or planning

purposes this area typically e*tends to up to 1, nm offshore% but would

e*clude any /1 designated areas. 0n practice% satisfactory coverage may often

be achieved out to around +,, nm offshore S/S Chapter% 0'% and eg. 2-

1+!.

Sea area A3 means an area% e*cluding sea areas /1 and /2% within the

coverage of an International Mobile Satellite Organization 0nmarsat!

geostationary satellite in which continuous alerting is available% "his area lies

between about latitudes 345 north and 345 south% but e*cludes /1 and6or /2

designated areas S/S Chapter 0'%eg. 2-17!.

Sea area A4 means an area outside sea areas /1% /2 and /+. "his is

essentially the 8olar egions% north and south of about 345 of latitude% but

e*cludes any other areas S/S Chapter 0'%eg. 2-1!.


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Carriage requirements

-(uipment carriage re(uirements for ships at sea depend upon the sea area in hich theship is sailing. >urthermore, ships operating in the GMDSS are re(uired to carry a primaryand a secondary means of distress alerting. This means ha!ing =6>+DSC as a primarysystem for a ship near coastal areas, bac$ed up by a satellite /%eren! PositionIndi$tin ,$dio Be$on)-%I. & ship operating in an oshore ocean area could ha!eMedium >re(uency DSC, 6igh >re(uency DSC or Inmarsat satellite communications as aprimary system bac$ed up by a satellite -%I. The type of e(uipment used in the primarysystem is determined by the sea area in hich the ship ill be na!igating.

The carriage re(uirements are de*ned in SO9&S Chapter I=, eg. : to 1 for the four seaareas. Table / shos ho the SO9&S egulations ould translate into the bare minimumcarriage re(uirements for the four sea areas. The ma#ority of ships ill, hoe!er, be *ttedith a more comprehensi!e radio installation.

2*1*+*1 Details of e(uipmentspeci*cations

",uipment %2 Sea area %+ Sea area %-

./F with !SC 0 0 0 0

S%$( or %ISS%$( 23 0 0 0 0

#%.("0 receiver 0 0 0 0

"C receiver 0 0 0

"'I$4 0 0 0 0

./F portable 2 or +3 0 0 0 0

MF telephony with !SC 0 0 0

Inmar5at4 or Inmar5atC 0 or

MF6/F telephony with !SC andtele7 0 0

(able 1 /uip%ent spei$tion

Aotes? 0e(uired in those sea areas here the A&=T- ser!ice is a!ailable.

e(uired in those sea areas here the A&=T- ser!ice is AOT

a!ailable. The -GC recei!e facility may be included in the standard

Inmarsat+C terminal.

0 ;5E M62 COS%&S+S&S&T -%I


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E5 MOD-9 CO3S- /.


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.o%pendiu%

2*1*+*2 et$ils o& $rri$e reuire%ents

-!ery ship shall be pro!ided in accordance ith SO9&S I=, eg. :?

@@ a =6> radio installation capable of transmitting and recei!ing DSC andradiotelephony )Minimum ch:5, ch5E, ch/7 and ch/E

@@ a radio installation capable of maintaining a continuous DSC atch on =6> channel:5 )ch:5

@@ a search and rescue locating de!ice capable of operating either in the 1 G62band or on fre(uencies dedicated for+uto%$ti Identi$tion S!ste%)&IS

@@ a recei!er capable of recei!ing international N$i$tion$l 4e5t #ess$e)A&=T-ser!ice broadcasts if the ship is engaged on !oyages in any area in hich aninternational A&=T- ser!ice is pro!ided

@@ a radio facility for reception of maritime safety information by the Inmarsatenhanced group calling system if the ship is engaged on !oyages in any area ofInmarsat co!erage but in hich an international A&=T- ser!ice is not pro!ided

@@ an -%I hich shall be capable of transmitting a distress alert through the polarorbiting satellite

ser!ice operating in the ;5E M62 band

@@ e!ery passenger ship shall be pro!ided ith means for to on+scene radiocommunications

for search and rescue purposes using the aeronautical fre(uencies / DSC on


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-%I )CospasFSarsatS&T andFor &IS+S&T


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Sea %rea %+ =6> DSC on channel :5 )for ships in a range of 75 nmM> DSC on DSC on 0;/;.4 $62 and all other 6> DSC fre(uencies-%I )CospasFSarsat

S&T andFor &IS+S&T

Sea %rea %- =6> DSC on channel :5 )for ships in a range of 75 nmM> DSC on DSC on 0;/;.4 $62 and all other 6> DSC fre(uencies-%I )CospasFSarsatS&T andFor &IS+S&T

2*1*+*8 Bride $l$r% p$nel $nd its purpose

& distress alarm panel is a de!ice hich ma$es it possible to initiate transmission of distressalerts by the radiofrom the position from hich the ship is normally na!igated. It is normally connected

=6> DSC, M>DSC and Inmarsat+C terminal )SO9&S Chapter I=, eg. 1 to //.

2*1*+*9 ,euire%ents &or r$dio s$&et! erti$tes

& Cargo Ship Safety adio Certi*cate shall be issued after an initial or reneal sur!ey to acargo ship hich complies ith the rele!ant re(uirements of SO9&S Chapter I= by the&dministration under hich ag the !essel is sailing. The !alidation of the certi*cate shall note"ceed *!e years )SO9&S Chapter I, eg. /< and /7.


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.o%pendiu%

:atchkeeping

2*1*-*1 $theepin proedures $s dened in the ,$dio ,eul$tions

Ships, hilst at sea, shall maintain a continuous atch appropriate to the sea area in hich

the ship is sailing )SO9&S Chapter I=, eg. / DSC channel :5

@@ M> DSC distress and safety fre(uency DSC distress and safety fre(uencies? 0;/;.4 $62 and also on at least one ofthe distress and safety DSC fre(uencies ; channel /E, if practicable

@@ an Inmarsat Ship /$rth St$tion)S-S )if the ship is *tted ith for satellite shore+

to+ship distress alerts@@ a radio atch for broadcasts of #$riti%e S$&et! In&or%$tion)MSI on the appropriate

fre(uency or fre(uencies on hich such information is broadcast for the area inhich the ship is na!igating

& continuous atch for broadcasts of MSI shall also be $ept, for the area in

the ship is sailing, by? @@ A&=T- )4/0 $62 recei!er

@@ Inmarsat+C or /nh$ned roup .$ll)-GC Safetyrece @@ 6> tele"

2*1*-*2 ther '$theepin proedures

'eather and na!igational arnings times throughout the day by coast stations on M>, 6>and =6>.

The IT3 9ist of Special Ser!ice Stations should be consulted for further details. Aationalpublications, *isto& ,$dio Sin$ls )&9S =ol. 4, may be consulted as useful additional aids. Detailed radiocommunicationset forth in part &, chapter =III and part , chapter =III of the International Con!ention onStandards of Training, Certi*cation and 'atch$eeping for Seafarers, /1:0 as amended)STC' Con!ention as ell as in the Chapter =II &rt. 7/@/< to 7/@or stations on board ships hich sail beyond the range of =6> coast stations?

@@ & holder of a *rst+ or second+class adio -lectronic Certi*cate or a ener$lper$tors.erti$te )GOCB

@@ >or stations on board ships hich sail ithin the range of =6> coast stations?

@@ & holder of a *rst+ or second+class adio -lectronic Certi*cate or a GeneralOperator8s Certi*cate or a ,estrited per$tors .erti$te)OC.


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MO


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&n OC only co!ers the operation of GMDSS e(uipment re(uired for GMDSS sea area &/,and does not co!er the operation of GMDSS &


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Today, the apply to fre(uencies ranging from 1 $62 to ;55 G62, and incorporate o!er/,555 pages of information describing ho the spectrum must be used and shared aroundthe globe. In an increasingly uniredJ orld, some ;5 dierent radio ser!ices compete forallocations to pro!ide the spectrum needed to e"tend applications or support a largernumber of users.

Co!ering both legal and technical issues, these egulations ser!e as an international

instrument for the optimal international management of the spectrum co!ering radio andcommunication procedures.

The four !olumes of the are published ith their &rticles, &ppendices, esolutions andecommendations by the IT3. The regulations regard, among other things, to?

@@ Operational procedures

@@ Distress, urgency and safety

signals @@ &uthority of the master

@@ Secrecy of

correspondence @@ Ship

station licences

@@ Inspection of stations

@@ adio Operator8s Certi*cates

@@ >re(uencies

@@

'atch$eeping

@@ Identi*cation of radio stations

Authority of the master

The ser!ice of a ship station is placed under the sole authority of the master or of the

person responsible for the ship or other !essel carrying the station. The person holding thisauthority shall re(uire that each operator comply ith the and that the ship station forhich the operator is responsible is used, at all times, in accordance ith the .

The master or the person responsible, as ell as all persons ho may ha!e $noledge of thete"t or e!en of the e"istence of a radio telegram, or of any information hate!er obtained bymeans of the radio communication ser!ice, are placed under the obligation of obser!ing andensuring the secrecy of correspondence.

Secrecy of correspondence

The holder of a radio station licence is re(uired to preser!e the secrecy oftelecommunications, as pro!ided in the .

&dministrations shall underta$e the necessary measurements to prohibit and pre!ent theunauthori2ed interception of radio communications not intended for the general use of thepublic or other than that hich the station is authori2ed to recei!e. The di!ulgence of thecontents, simple disclosure of the e"istence, publication of any use hate!er, ithoutauthori2ation of information of any nature hate!er obtained by the interception of radiocommunications is forbidden.


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In cases here unauthori2ed correspondence is in!oluntarily recei!ed it shall not bereproduced, nor communicated to third parties, nor used for any purpose. -!en itse"istence shall not be disclosed.

Ship station licences

Ao transmitting station may be established or operated by a pri!ate person or by anyenterprise ithout a licence issued in an appropriate form and in conformity ith the pro!isionsof these regulations by or on behalf of the go!ernment of the country to hich the station in(uestion is sub#ect ), Chapter =, and &rt. /0.

The go!ernment hich issues a licence to a mobile station or a mobile earth station shallindicate therein in clear form the particulars of the station, including its name, call signand, here appropriate, the public correspondence category, as ell as the generalcharacteristics of the installation.

To facilitate the !eri*cation of licences issued to mobile stations and mobile earth stations,a translation of the te"t in one of the or$ing languages of the 3nion shall be added, hennecessary, to the te"t ritten in the national language.

Inspection of stations

Radio Operators Certicates

The ser!ice of e!ery ship radiotelephone station, ship earth station and ship station using thefre(uencyes and techni(ues for GMDSS, as prescribed in Chapter =II of the , shall be controlled by anoperator holding a certi*cate issued or recogni2ed by the go!ernment to hich the station issub#ect. %ro!ided the station is so controlled, other persons besides the holder of the certi*catemay use the e(uipment ), Chapter I, &rt. ;:.

2.2.4. Inspection of stations

"he governments or appropriate /dministrations of countries which a ship station orship earth station visits may re&uire the production of the licence for e*amination."he operator of the station% or the person responsible for the station% shall facilitatethis e*amination. "he licence shall be kept in such a way that it can be producedupon re&uest. /s far as possible% the licence% or a copy certified by the authoritywhich has issued it% should be permanently e*hibited in the station.

"he inspectors shall have in their possession an identity card or badge% issued by thecompetent authority% which they shall show on re&uest of the master or personresponsible for the ship or other vessel carrying the ship station or the ship earthstation.

hen the licence cannot be produced or when manifest irregularities are observed%governments or administrations may inspect the radio installations in order to satisfythemselves that these conform to the conditions imposed by the s.0n addition% inspectors have the right to re&uire the production of the operators9certificates% but proof of professional knowledge may not be demanded.hen a government or an /dministration has found that the operators9 certificatescannot be produced% then this /dministration must inform the /dministration under

which the ship station or ship earth station is registered as soon as possible./ccording to S/S egulations the radio stations of passenger ships includingthose used in life-saving appliances shall be sub


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Frequencies

2*2*9*1 Inter&erenes

&ll stations are forbidden to carry out unnecessary transmissions, or the transmission ofsuperuous signals, or the transmission of false or misleading signals, or the transmission ofsignals ithout identi*cation. Transmitting stations shall radiate only as much poer as isnecessary to ensure a satisfactory ser!ice.

In order to a!oid unlaful interferences

*1 locations of transmitting stations and, here the nature of the ser!ice permits,

locations of recei!ing stations shall be selected ith particular careB

*2 radiation in and reception from unnecessary directions shall be minimi2ed byta$ing the ma"imum practical ad!antage of the properties of directionalantennas hene!er the nature of the ser!ice permitsB

*+ the choice and use of transmitters and recei!ers shall be in accordance ith thepro!isions of the .

Special consideration shall be gi!en to a!oiding interference on distress and safetyfre(uencies.

The class of emission to be employed by a station should be such as to achie!e minimuminterference and to assure eHcient spectrum utili2ation.

MOD-9 CO3S- /.


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2*2*9*2 "se o& #F :F ;:F ":F $nd S:F &reuen! b$nds in the ##S

>or the allocation of fre(uencies the orld has been di!ided into three egions as shonon the folloing map.

$egion 1 $egion 2 $egion +

/ E5E.4+/ EI-D >I-D

M&Itime MOI9- MOI9- MOI9-9&AD MOI9- O&DC&STIAG &DIO9OC&TIOA

&DIO9OC&TIOA &DIOA&=IG&Tion

/ E74+/ 055 / :54+/ 055 / 055+< 555

>I-D >I-D &M&T-3M&Itime MOI9- MOI9- >I-D

9&AD MOI9- &DIO9OC&TIOA MOI9- e"cept aeronautical mobile&-Ona3TIC&9 &DIOA&=IG&Tion

&DIOA&=IG&Tion &DIO9OC&TIOA

/ 045+< 555 / 045+< 555 < 555+< 5E4>I-D &M&T-3 >I-D

MOI9- e"cept aeronauticalmobile >I-D MOI9-MOI9- e"cept aeronautical mobile

&DIO9OC&TIOA&DIOA&=IG&Tion

< 555+< 5I-D >I-D M&Itime MOI9-

MOI9- e"cept aeronautical mobile) MOI9-

"o avoid mutual interferences there are certain $) fre&uency bands allocated foreach region. 0n addition other fre&uency bands can also be used regardless of the

region. /s shown in the table below single fre&uency bands can be allocated todifferent radio services in the appropriate regions. "he use of single fre&uencies ineach $) band in its region is allocated by the responsible /uthority of each country.


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$egion 1 $egion 2 $egion +

1 606.5-1 6 2 5

)0?@D $ / 1 0 " 0 $ @

$=0@ . / A D $ - = 0 . @

1 635-1 8 0 0

)0?@D $ / 1 0 " 0 $ @ $=0@ . / A D

$ - = 0 . @

1 850-2 0 0 0

) 0 ? @ D $=0@ e*cept a e r o n a u t i c a l m o b i l e

2 000-2 0 2 5

) 0 ? @ D $=0@ e*cept aeronautical mobile 1 !

2 045-2 1 6 0

)0?@D $ / 1 0 " 0 $ @ $=0@ . / A D

$ - = 0 . @

2 170-2 1 7 3 . 5

$/0"0$@ $ - = 0 . @

2 173.5-2 1 9 0 . 5

$=0@ distress and c a l l i n g !

2 190.5-2 1 9 4

$/0"0$@ $ - = 0 . @

2 194-2 3 0 0


2 300-2 4 9 8

) 0 ? @ D

$=0@ e*cept aeronautical mobile 1 != 1 - / D C / S " 0 A #

2 502-2 6 2 5

) 0 ? @ D

$=0@ e*cept aeronautical mobile 1 !

2 625-2 6 5 0

$/0"0$@ $=0@ $ / 1 0 " 0 $ @ 1 / D 0 - A / ' 0 # / " 0 - A

2 650-2 8 5 0

) 0 ? @ D

$=0@ e*cept aeronautical mobile 1 !

1 625-1 7 0 5

) 0 ? @ D

$ - = 0 . @ = 1 - / D C / S " 0 A # 1 / D 0 - . - C / " 0 - A

1 705-1 8 0 0

)0?@D $ - = 0 . @1 / D 0 - . - C / " 0 - A/ @ 1 - A / B " 0 C / .

1 / D 0 - A / ' 0 # / " 0 - A

1 850-2 0 0 0

/ $ / " @ B 1) 0 ? @ D

$=0@ e*cept aeronautical m o b i l e1 / D 0 - . - C / " 0 - A

1 / D 0 - A / ' 0 # / " 0 - A

2 000-2 0 6 5

) 0 ? @ D

$ - = 0 . @

2 065-2 1 0 7

$/0"0$@ $ - = 0 . @

2 107-2 1 7 0

) 0 ? @ D$ - = 0 . @

2 170-2 1 7 3 . 5

$/0"0$@ $ - = 0 . @

2 173.5-2 1 9 0 . 5

$=0@ distress and c a l l i n g

2 190.5-2 1 9 4

$/0"0$@ $ - = 0 . @

2 194-2 3 0 0

) 0 ? @ D$ - = 0 . @

2 300-2 4 9 5

)0?@D $ - = 0 . @= 1 - / D C / S " 0 A #

2 505-2 8 5 0

) 0 ? @ D$ - = 0 . @

3 155-3 2 0 0


1 606.5-1 8 0 0

) 0 ? @ D

$ - = 0 . @ 1 / D 0 - . - C / " 0 - A 1 / D 0 - A / ' 0 # / " 0 - A

1 800-2 0 0 0

/ $ / " @ B 1) 0 ? @ D

$=0@ e*cept aeronautical m o b i l e1 / D 0 - A / ' 0 # / " 0 - A1 / D 0 - . - C / " 0 - A

2 000-2 0 6 5

) 0 ? @ D$ - = 0 . @

2 065-2 1 0 7

$/0"0$@ $ - = 0 . @

2 107-2 1 7 0

) 0 ? @ D$ - = 0 . @

2 170-2 1 7 3 . 5

$/0"0$@ $ - = 0 . @

2 173.5-2 190.5 $ - = 0 . @

distress and c a l l i n g !

2 190.5-2 1 9 4

$/0"0$@ $ - = 0 . @

2 194-2 3 0 0

) 0 ? @ D

$ - = 0 . @

2 300-2 4 9 5

)0?@D $ - = 0 . @= 1 - / D C / S " 0 A #

2 505-2 8 5 0

) 0 ? @ D$ - = 0 . @

3 155-3 200 ) 0 ? @ D $=0@ e*cept aeronautical mobile 1 !

3 200-3 2 3 0


= 1 - / D C / S " 0 A #


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2.2.6.5. T%e concept of 'F frequenc* $ana+e$ent

0n the different () bands between 7 $(> and 24 $(> certain fre&uencies areallocated for the purpose of radiotelephony% radio tele* A=D8!% facsimile fa*!% dataand transmission. "he fre&uency plan and channelling system are enlisted in the

s appendi* 13 and in appendi* 1, - 17 of this compendium.

2.2.6.6. ('F te!ep%on*

"he '() maritime band between about 14 $(> and 137 $(> is split into 7channels with a bandwidth of 2 k(> each. "he channel spacing of 12% k(> can beused if the neighbouring authorities agree. "he list of '() channels and theirfre&uencies can be found in the s appendi* 1 and in appendi* of thiscompendium.

2.2.6.,. Frequencies for distress& ur+enc* and safet* co$$unications

/SC R0 /SC T0 RTCO# / /irection

c % ,

2 1 , & 5

4 2 , & 5

6 3 1 2 &

4 1 4 & 5

1 2 5 , , &

1 6 4 & 5

c % ,

21,&5

42,&5

6312&

414&5

1 2 5 , , &

1 6 4 & 5

c % 1 6

2 1 2 &

4 1 2 5 &

6 2 1 5 &

2 7 1 &

1 2 2 7 &

1 6 4 2 &

2 1 , 4 & 5

4 1 , , & 5

6 2 6 &

3 , 6 & 5

1 2 5 2 &

1 6 6 7 5 &

SS& SCS& Area

SS& SCS& Area

SS& SCS& Area

SS& SCS& Area

SS& SCS& Area

SS& SCS& Area

SS& SCS& Area

Ta!e 5" /istress 8 )r+enc* 8Safet* Frequencies -#F8'F in 9':

2.2.6.. Frequencies for routine co$$unication and rep!*

/SC R0 /SC T0 RTCO# / /irection

c% ,

21,,&

21,,&

4217&5

6331&

436&51 2 6 5 , &

1 6 7 3 &

1 7 , 3 & 5

2 2 4 4 4 &

2 6 1 2 1 &

c % ,

21,,&

217&5

42&

6312&5

415&1 2 5 , , & 5

1 6 5 &

1 7 & 5

2 2 3 , 4 & 5

2 5 2 & 5

( ' F ; o r 9

# F ; o r 9

C o a s t ; o r 9

C o a s t ; o r 9

C o a s t ; o r 9

C o a s t ; o r 9C o a s t ; o r 9

C o a s t ; o r 9

C o a s t ; o r 9

C o a s t ; o r 9

C o a s t ; o r 9

# F ; o r 9

C o a s t ; o r 9

C o a s t ; o r 9

C o a s t ; o r 9

C o a s t ; o r 9C o a s t ; o r 9

C o a s t ; o r 9

C o a s t ; o r 9

C o a s t ; o r 9

C o a s t ; o r 9

SS& SCS& A r e a

SS& A r e a

SCS

SCS

SCS

SCSSCS

SCS

SCS

SCS

SCS

Ta!e 6 Routine frequencies in -#F8'F in 9':


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2*2*;*2 "ren!

The transmission of an urgency announcement and an urgency call and message indicatesthat

@@ the folloing information refers to an urgent need for

assistance or @@ a medical transport or

@@ a medico callFmessage.3rgency communications shall ha!e priority o!er all other communications, e"cept distresscommunication.

2*2*;*+ S$&et!

The transmission of a safety announcement and a safety call and message indicates that

@@ the folloing informations refer to the safety of

na!igation, @@ eather conditions,

@@ nautical arnings or

@@ the ship mo!ement communication.

Safety communications shall ha!e priority o!er all other communications, e"cept distressand urgency communication.

2.2.,.4. Routine

"he transmission of a routine announcement and a routine call and messageindicates that the following information9s refer not to distress- urgency- or safetypurposes. outine communications shall have no priority.

2.2.. ;atc%9eepin+

Coast stations assigned with watch-keeping responsibilities in the #$DSS shall

maintain an automatic DSC watch on fre&uencies and for periods of time as indicated

Ship stations, appropriately e(uipped, shall, hilst at sea, maintain an automatic DSC atch onthe appropriate distress and safety calling fre(uencies in the fre(uency bands in hich they areoperating. Ship stations, hich ha!e the appropriate e(uipment shall also maintain atch onthe appropriate fre(uencies for the automatic reception of transmissions of meteorological andna!igational arnings and other urgent information to ships.

Ship stations complying ith the pro!isions of the should, here practicable, maintaina atch on the fre(uency /4E.0 M62 )=6> channel /E.

Ship earth stations complying ith the pro!isions of the shall, hile at sea, maintainatch e"cept hen communicating on a or$ing channel.

RECOR!EE"I#$ %radio log&oo'(

$adio log

eferences?

@@ IT3 &pp /E, Section I, item

7 @@ SO9&S, Chapter I=,

egulation /:

Ship stations for hich a GMDSS installation is re(uired by international agreement )SO9&Sshall be pro!ided ith a radio log in hich the folloing are recorded as they occur, together

ith the time of the occurrence?@@ a summary of communications relating to Distress, 3rgency and

Safety traHcB @@ a reference to important ser!ice incidents.

:< MOD-9 CO3S- /.


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.o%pendiu%

In addition, records are re(uired to be maintained in the radio logboo$ for?

@@ %eriodical testing of adio

-(uipment @@ %eriodical testing of

emergency batteries

@@ Designated oHcers ho ill operate the e(uipment

+ Identi


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Details of call sign series for each country ill found in appendi" /4 of this Compendium.


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)aritime )o&ile Ser*ice Identity

Ships participating in the maritime radio ser!ices should be assigned a nine digit uni(ueship station identity in the format

$roup calling num&er

Group ship station call identities for calling simultaneously more than one ship are formedas follos?

@1M2I+!-08090;0A0B

The *rst *gure is 2ero and is any *gure from 5 to 1. The MID represents only the territoryor geographical area of the &dministration assigning the group ship station call identityand does not therefore pre!ent group calls to eets containing more than one shipnationality.

Identi 55 stations. It is not applicable to M> or 6> coast stations.

Identi


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The &dministration may use the si"th digit to further dierentiate beteen certain speci*cuses of this class of MMSI, as shon in the e"ample applications belo?

@@ @@MI!1000 Coa5t radio 5tation5

@@ @@MI!2000 /arbour radio 5tation5

@@ @@MI!+000 'ilot 5tation5> etc*MOD-9 CO3S- /.


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Identi


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@@ Inmarsat >leet starts ith number :E, all in all 1+

digits and @@ E5 for high speed data, all in all 1+digits

:E "


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.o%pendiu%

- Service publication5

Li5t of Coa5t Station5 and Special Service Station5 I( Li5t I.3

Li5t of Ship Station5 and Maritime Mobile Service Identity %55ignment5I( Li5t .3

The 9ist of Ship Stations and Maritime Mobile Ser!ice Identity &ssignments )9ist = is aser!ice publication prepared and issued, once a year, by the IT3, in accordance ithpro!ision no.


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4.2. ?ist of S%ip Stations and #ariti$e #oi!e Ser>ice Identit* Assi+n$ents-IT) ?ist (

Fi+ure 7" ?ist of S%ip Stations and #ariti$e #oi!e Ser>ice Identit* Assi+n$ents

"he ist of Ship Stations and $aritime $obile Service 0dentity /ssignments ist '! isa service publication prepared and issued% once a year% by the 0"B% in accordancewith provision no. 2,. of the .

4.3. #anua! for use * t%e #ariti$e #oi!e and #ariti$e #oi!eSate!!iteSer>ices

Fi+ure 1" #anua! for )se * t%e #ariti$e #oi!e and #ariti$e #oi!eSate!!ite Ser>ices

"he $aritime $obile and $aritime $obile-Satellite Services reflects the regulatoryprovisions and the latest decisions concerning those services by 0"B conferencesincluding relevant decisions pertaining to the introduction of new systems and

techni&ues!. /s prescribed in appendi* 14 of the % the $anual is re&uired to becarried in stations on board ships.

"he $anual for use by the $aritime $obile and $aritime $obile-Satellite Services ispublished in accordance with /rticle 2, Ao. 2,.17! of the % and results fromstudies carried out in the 0"B- since 2,,. @dition 2,1+ comprises two volumes% notsold separately. 'olume 1 provides descriptive te*t of the organi>ation and operationof the #$DSS and other maritime operational procedures% while volume 2 containsthe e*tracts of the regulatory te*ts associated with maritime operations.


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.o%pendiu%

The Manual for use by the Maritime Mobile and Maritime Mobile+Satellite Ser!ices ispublished in accordance ith &rticle


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8 (echnical

$adio wave propagation

The radio a!e is needed to carry the signal information eHciently and ithout distortion.In the case of audio fre(uencies, hich may range from about 4562 to /4 $62, it ould notbe technically feasible to radiate the information directly from a practical transmitter andantenna. )Try to calculate the a!elength by the abo!e mentioned formula ith the /4 $62fre(uency. Then you ill see the impractical si2e of the antenna you need for such atransmission.

6igher fre(uencies can radiate eHciently from antennas ha!ing dimensions typicallybeteen a (uarter and one a!e length. Thus, practical communication systems use aradio a!e to carry the audio or other )e.g. !ision or data information beteen thetransmitting and recei!ing sites.

Three main physical mechanisms go!ern the propagation of radio a!es?

Line of

5ightroundwaveSky

wave-ach fre(uency range has its on propagation characteristic.The reliability

connection beteento

stations ith a transmitter and a recei!er depends on the choiceof the fre(uencyThe ,$dio Fre1uen0!)> spectrum isdi!ided

Fre,uency 4and

/4 $62 @ 75 $62 9>

75 $62 @ 755 $62

755 $62 @ ; M62 >

; M62 @ 75 M62

75 M62 @ 755 M62 =ery 6igh >re(uency )=6>

755 M62 @ 7 G62 3ltra 6igh >re(uency )36>

7 G62 @ 75 G62Super 6igh >re(uency)S6>

75 G62 @ 755 G62 -"tra 6igh >re(uency )-6>

(able ; Freuen! b$nds

+asics

/ui$lent bet'een '$elenth $nd &reuen!

adio a!es radiate at the !elocity of light, 755 " /5E m per second. The e(ui!alentbeteen the eloit! o& liht )c, &reuen! )f and the '$elenth ) i.e. longera!elength corresponded to loer fre(uency, shortera!elength to higher fre(uency.

f N number of cycles per second

c N !elocity of light 755 " /5E metres per second )755555 $m per second

N a!elength in metres


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05 MOD-9 CO3S- /.


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.o%pendiu%

Figure 12 /5$%ple o& '$elenth

Subdiision o& the %ost sini$nt p$rts o& r$dio spetru% used in #$riti%e #obile

Serie (##S)

ire(uency )M>. A&=T-, DSC

; M62 @ 75 M62 6igh >re(uency )6>.A&=T-, DSC, =oice,Tele" and Data communication

75 M62 @ 755 M62 =ery 6igh >re(uency )=6>. DSC, =oice, Data communication

755 M62 @ 7 G62 3ltra 6igh >re(uency )36>.=oice communication,Satellite communication

Ta!e " Frequenc* ran+es and t%eirapp!ications


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&bo!e about 45 M62, propagation is essentially by line+of+sight. This is accomplished, inthe case of terrestrial radio, !ia the loer part of the atmosphere @ termed the troposphere@ and in the case of space communication !ia earth+orbiting satellites.

>igure /7? 9ine of sight propagation shos a styli2ed terrestrial radio lin$. In general, the

recei!ed signal is the sum of a direct signal along path a, clear of the ground, and se!eralreected signals along paths such as b and c. ecause a radio signal undergoes a phasere!ersal at the reection point, the theoretical situation is that the direct and reectedsignals should cancel out if the recei!er antenna is at ground le!el.

Since land has poor ground conducti!ity, total cancellation does not occur in practice, assimple e"periment ith portable =6> >M recei!er ill sho. 6oe!er, the sea is a !ery goodconductor, hich means that maritime =6> antennas should be mounted ell abo!e the sea inorder to a!oid se!ere cancellation eects.

Ground a!es and s$y a!es

In principle, a transmitting antenna sited at the earth8s surface ill set up a surface a!ehich follos the cur!ature of the earth. The distance, o!er hich reliable communicationscan be achie!ed by the surface, or ground a!e, depends on the fre(uency and thephysical properties )i.e. ground conducti!ity and dielectric constant of the earth along thetransmission path. & ground a!e can only be established ith useful eHciency here thea!elength is greater than se!eral tens of metres.

Seaater has the highest conducti!ity and ill support the propagation of a ground a!e,in much the same manner as a metal plate. &t the other end of the scale, an arid desertpro!ides !ery lossy ground conditions and ill not support the eHcient propagation onground a!e signal.

The signi*cance of this for maritime communications is that long distance or$ing ispossible at medium to lo fre(uencies using only modest transmitter poer compared tothose for broadcasting at similar fre(uencies o!er land.

>igure /7? 9ine of sight propagation also shos surface a!e propagation o!er a terrestrialradio lin$. In principle, the recei!ed signal ill be the sum of the line+of+sight signals andthe surface a!e. In practice, hoe!er, one or other of the to components ill

predominate depending on the transmission fre(uency and length of the radio lin$. Grounda!e propagation predominates at M>, 9> and =9>.

'ithin the fre(uency range of / @ 75 M62, ionospheric reection is the controlling factor inachie!ing long+distance communications by radio a!es.

0< MOD-9 CO3S- /.


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.o%pendiu%

Ionosphere structure

9ong+distance propagation of radio a!es at 6> is mainly the result of single or multiplereections from ioni2ed regions in the upper atmosphere $non collecti!ely as theionosphere. These ioni2ed regions are generated at heights of /55 @ ;55 $m )44 @ < layers combines to form a single >+layer atappro"imately and 9> fre(uencies the D+layer is suHciently reecti!e to guide signals beteen theground and the bottom of the D+layer for se!eral thousand $ilometres ith littleattenuation.

Fi+ure 15" S9* e radio pat%

=ecause the ioni>ation process in the upper atmosphere is responsible for thiseffect that is caused by the sun% it will be evident that the density of ioni>ation willvary with the time of day and the season of the year. "he sunspot cycle% whichtakes appro*imately 11years% also has an effect. 0onospheric storms andother disturbances occur from time to time and G in e*treme cases G can cause acommunication black-out lasting for some days.

0n general% the net result is that% to communicate over a given distance% a higher

fre&uency is necessary when the density of ioni>ation is high and a lower fre&uencywhen the density of ioni>ation falls.


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Ionospheric reection may be simply described as the phenomenon hereby a a!eappears to undergo reection on reaching a suitable ioni2ed region. >ree electrons are setin motion so as to re+radiate the a!e in a changed direction. &s it passes through theioni2ed layers, the a!e may e!entually be reected bac$ to the earth. On a simpli*ed!ie the eect may be !ieed as reection from an area at hat is termed the mirror

height.

The eect is fre(uency+dependent, ith a greater degree of ioni2ation being necessary tocause reection as the fre(uency is increased. 3sually the higher layers ha!e the greaterdegree of ioni2ation and therefore reect the highest fre(uencies. ecause of the greatermirror height, the communication range achie!ed by a single reection ill also begreatest under these circumstances.

The solar radiation responsible for ioni2ing the atmosphere !aries continuously from day tonight and beteen the seasons. Sunspot acti!ity also has a strong underlying eect on thedegree of ioni2ation. The le!el of sunspot acti!ity !aries o!er a cycle of around // years,ith periods of ma"imum ioni2ation occurring hen the number of sunspots is at ama"imum.

)or satellite communications an unobstructed view of the satellite is re&uired% and the ship earth stationantenna must be mounted to achieve the best view to the satellite possible.)or terrestrial communications the range depends upon the heights of both the transmitting andreceiving antenna. =ecause of a slight bending effect on radio waves in the troposphere% causedmainly by water vapor% the radio hori>on is in fact greater than the optical hori>on by factor of 76+.

"aking this factor into account% the ma*imum range at sea is given by the formula

ange in nm H 7 * I "* ft! J 7* ft!K ange in nm H 2.22 * I "* m! J :* m!K

ange in km H 7.12* I "* m! J * m!K

here "* and * are the heights of the transmitting and receiving antenna above sea level%measured in feet or meters as indicated.

8*1*9 )F propagation

$! prop$$tion

M> communications depend mainly on ground+a!e propagation but ith a furtherreduction in range because of the increased eect of attenuation by the earth.

& coast station can achie!e good ground a!e co!erage for !oice communications up to445 $m )755 nm. Ship stations, ith less poerful transmitters and less elaborateantenna systems, can usually e"pect reliable ground a!e communications up to


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0; MOD-9 CO3S- /.


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Mail to Cape Ton during daytime is possible on


46/282


'hen transmitting east to est, the signal may pass from daytime to night+timeconditions, and it may be !ery diHcult to establish eecti!e communications. One strategyis to estimate the optimum transmission band according to the dayFnight conditions at themidpoint of the radio circuit. The best course of action may be to ait until the entire pathbeteen the to stations is in daylight or dar$nessFnight+time.

#$5i%$l us$ble &reuen!

The M3> hich is reected by the ionosphere o!er any particular path is $non as theM3>. The M3> depends on?

*1 the time of the dayB

*2 seasonB

*+ latitudeB and

*-period of sunspotcycle.

ecei!ers at "< and "7 can recei!e signal by reection from the ionosphere from points

%< and %7 respecti!ely. The point %< represents the location nearest the transmitter herereection can ta$e place at the fre(uency being used. The distance from the transmitter to"< is termed the SLI% DIST&AC- and represents the minimum distance here s$y a!epropagation ill be eecti!e at this fre(uency. &t point %/ the le!el of ioni2ation is notsuHcient to return a signal to earth. The recei!er "/ represents the point at hich asignal can still be recei!ed by ground a!e propagation from the transmitter. There illtherefore be a region, $non as the SLI% POAe, here propagation by both ground a!eand s$y a!e is !ery poor and little useful signal ill be recei!ed.

&t points nearer to the transmitter no signals ill be recei!ed by ionospheric reection, buthen suHciently close to the transmitter )recei!er "/ in >igure /;? Ground a!es and s$ya!es to be ithin range of the ground a!e the signals ill again be heard. In beteen thereis an area of !ery poor reception, termed the s$ip 2one. The distance from the transmitter tothe nearest point, at hich a a!e at a particular operating fre(uency returns, after reection,bac$ to the earth )recei!er "


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0E MOD-9 CO3S- /.


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.o%pendiu%

The critical a!e angle for a particular layer depends on the operating fre(uency anddecreases as the fre(uency increases. In conse(uence, the s$ip distance increases ithfre(uency.

The M3> therefore represents a limit, hich must not be e"ceeded for the recei!er to

remain in the area of reception #ust beyond the s$ip 2one. The result is that the s$ipdistance e"tends toards the recei!er as the operating fre(uency approaches the M3>.The reecting layer also absorbs 6> radiation, and this eect decreases mar$edly as theoperating fre(uency approaches the M3>.

The combined eect is that, for any particular radio circuit, the optimum or$ingfre(uency lies #ust belo the M3> for the particular path. &ny rise in operating fre(uencyof fall in M3> ill result in a sudden drop+out of recei!ed signals as the s$ip 2one e"tendsto include the reception point.

*o'est us$ble &reuen! (*"F)

/s the operating fre&uency is reduced% the reflection will occur in the lower layers of the ionosphere.(owever% at lower altitudes% and in the D-layer especially% the energy in the wave is sub


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Sinle hop ondition

&n 6> radio circuit can also be set up by multiple reections beteen the ionosphereand the ground. =ariability and absorption increase ith each reection )or hop, so thesingle+reection )hop path, as described abo!e, is to be preferred for ma"imum circuitreliability.

To a!oid multiple+hop conditions it is ad!isable to aim for the M3> for the highestionospheric layer, in the e"pectation that this ill normally e"ceed the M3> for the loerle!els and thereby a!oid multiple reections in!ol!ing the loer layers.

(?F propa+ation

"he radio wave follows the curvature of the earthNs surface and is known as a ground wave. "he rangeof a ground wave signal is governed by the rate of loss of energy into the ground% which in turn isgoverned by the value of ground conductivity. "he attenuation of the ground wave is least overseawater and greatest over the rocky ground or deserts.

') signals are reflected well by the D-layer of the ionosphere% because the height of the D-layer is ofthe same order of wavelengths at ')% the net effect is of a waveguide for ') signals betweenthe ground and the D- layer. "he signal attenuation is very low under these conditions andtransmission paths up to 22,,, km 12,,, nm! are possible.

arge antenna arrays are normally used at ') with very high output transmitter powers 3, k! togive virtually world-wide coverage. ') transmissions are therefore only used in the shore to shipdirection. ') signals penetrate the sea to a depth of a few tens of meters% making them very effectivefor maintaining communications with submerged submarines.

?F propa+ation

/t )% ground wave propagation predominates% as with ')% and due to the higher fre&uency% the rangeis reduced% particularly over land% due to the relatively greater attenuation effect of poor groundconductivity as the wavelength is reduced. "he waveguide effect between the ground and the D-layerstill applies at )% and conditions are in fact more stable than at '). "here is also an improvement withregards to lower background noise levels at ). (owever the path attenuation is higher.

#odu!ation asics

"he simplest form of communication is $orse code% sent by switching the carrier fre&uency on and off ina se&uence of OdotsP and OdashesP. =ut the rate of information is relatively low% 2, to 2 words perminute is a good communication rate. =ut to transmit information by using $orse code a specialknowledge and ability is re&uired.

$odulation is the mechanism whereby a radio fre&uency carrier wave is used for the transmission ofinformation. 0n doing so the carrier fre&uency is changed by a useful signal. "hereby it becomespossible to transmit a low fre&uency useful DS=! signal on a high fre&uency. "he transmitting signalcovers a certain bandwidth which depends on the useful signal.

0n /$ the high-fre&uency amplitude is varied by a low-fre&uency useful signal.)$ is a mechanism in which the carrier fre&uency is altered by the signal to be transmitted.

!arro" #an$ %irect &rinting A=D8! is a method for radiotele*. )or this purpose% the telegraph signal

shifts the fre&uency of the carrier between predetermined values. 0n the maritime conte*t the type of

information carried is mainly speech or data


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.o%pendiu%

Frequency modulation

In the telecommunications, Freuen! #odul$tion)>M, code of emission? >7- con!eys

information o!er a carrier a!e by !arying its instantaneous fre(uency. This contrastsith +%plitude #odul$tion )&M, in hich the carrier is !aried hile the fre(uencyremains constant.

0n radiotelephony fre&uency modulation is also known as phase modulation code of emission #+@!when the carrier phase modulation is in time integral of the )$ signal. "he 0"B designatessome '() channels as )+@and others as #+@ but% as far as the operator is concerned% there is nodifference because a change in fre&uency of the carrier also results in a corresponding change in thephase of the carrier% and vice versa.

0n frequency shift 'eying )SL!% which is used for A=D8 a fre&uency of 13, (> is shifted about acertain centre fre&uency e.g.13,, (>! as OmarkP and OspaceP tones. 0.e. mark H 14 (> and space H13 (>.

Amplitude modulation

In &M the information modulated on to the carrier a!e appears as fre(uencies beloandFor abo!e the carrier fre(uency, $non as sidebands of a certain bandidthdepending on the nature of information.


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In radiotelephony each sideband re(uires a bandidth of


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.o%pendiu%

If the bandidth on the recei!er8s side is set too ide for the mode of transmission thenmore noise ill be apparent. &lso, greater interference from unanted stations or ad#acentfre(uencies ill be recei!ed. It ill reduce the recei!ing (uality of the anted station.

>re(uency and phase modulation )>7-FG7- generate se!eral sidebands abo!e and belo

the carrier for each modulation fre(uency hich depends on the depth of modulation. Thusthe occupied channel bandidth for a fre(uency+modulated !oice transmission is about /E$62.

In amplitude modulation the bandidth is much smaller than in >M. ecause igure igure /0. In the SS mode it is igure /1 and >igure .Thereby the carrier fre(uency is modulated by the content of information, either in >M or&M or >SL.

The assigned fre(uency is the centre of a fre(uency band assigned by an &dministration to astation or ser!ice.

O/cial designations of emission

IT3 adio egulations classify and symboli2e emissions according to their basiccharacteristics.

The basic characteristics are?

Fir5t5ymbolD type of modulation of the carrier

9etter % am double sideband transmissions

9etter / SS transmissions ith full carrier9etter F fre(uency modulation

9etter phase modulation

9etterE SS transmissions ith suppressed carrier

MOD-9 CO3S- /.


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Second 5ymbolD nature of 5ignal53 modulating the carrier

>igure 1 no modulating signal )e.g. Morse code

>igure 2 a single channel containing (uanti2ed or digital information ithout theuse of a

modulating sub+carrier

>igure + a single channel containing analogue information

>igure ; to or more channels containing (uanti2ed or digital information

(hird 5ymbolD type of information to be tran5mitted

9etter % telegraphy for aural reception

9etter 4 telegraphy for automatic reception

9etter " telephony

In maritime radio communications the folloing classes of emission are used?

%1%Signalling by $eying the carrier directly Morsecode

%2% DS modulated Morse code

/+"SS full carrier radiotelephony )in oldere(uipment $62

E+" SS suppressed

F+" >M radiotelephony

+" phase modulation

F14 fre(uency shift

E24 SS telegraphy for

0no/cial designations of emissions

esides the abo!e mentioned IT3 designated classes of emission there are se!eralunoHcial designations for dierent transmissions.

%M double side band telephony )commercial broadcast, &7

SS4 single sideband, suppressed carrier )K7-

C: morse code )&/&

(L0 radiotele" in >/ mode

(ran5mitter and receiver ba5ic5

1ransmitter structure

The radio fre(uency generator produces the carrier, i.e. the fre(uency on hich atransmission ill be carried out.

The modulator is used to combine the information signals from the microphone or thetele" ith the carrier. The type of modulation may be $%plitude )&M, &reuen!)>M or

ph$se)%M. This modulated signal is then ampli*ed ithin the transmitter and fed to theantenna.

The antenna re(uires tuning to the carrier fre(uency so that it ill radiate eHciently.&ntennas made from ire elements radiate most eHciently hen they are one (uarter of aa!elength long.


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1< MOD-9 CO3S- /.


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.o%pendiu%

Synthesiser Amplifier

1 6 Modulator 1W 25W

MIc. Data

Amplifier Modem

0t is not practicable to install an antenna on board ships% which is physically the ideal length coveringall of the $) or () bands. (owever% the electrical length of the antenna can be lengthened orshortened in respect to its physical length by the introduction of e*tra radio-fre&uency circuitelements% inductors and capacitors% in an(ntenna Tuning Unit /"B!.

0n most modern e&uipment% this is achieved automatically by pressing the Q"uneR button beforeactual transmission. / signal strength meter% which measures antenna current% gives a visual

indication of transmission. $ost e&uipment allows for $anual tuning mode on 212 k(> in case theautomatic tuning fails. 0ndividual manufactureNs manuals should be consulted for further details.

Recei*er structure

The anted signal is recei!ed by tuning the input to the recei!er to the anted fre(uency.ecei!ed signals !ary greatly in strength due to a number of factors, e.g.

*1 & local transmitter radiating high or lo poer.

*2 & distant station radiating high or medium poer.

*+ =ariations in the ionosphere, hich may aect signals on M> at night or on 6>

at any time@ polari2ation fading.

*- Simultaneous reception by ground and s$y a!es on M> at night, hich mayconstantly !ary in strength or phase and interact ith each other @ interferencefading.

*8 On the 6> bands, signals can reach the recei!er ha!ing ta$en dierent paths,again causing interference fading.

The radio fre(uency or control allos manual ad#ustment of the input

ampli*er so as to set up the gain to suit conditions. Continual ad#ustment of the gain control

may be necessary if fading occurs, in hich case the +uto%$ti $in .ontrol )&GC can be

sitched, thereby ta$ing o!er from manual control, i.e., the &GC holds the output at a nearly

constant le!el e!en though the input may uctuate idely.

MOD-9 CO3S- /.


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AGC

R/F TunedFrequency

Demodulator Audio

Amplifier J3E AmplifierChanger F1B H3E

Synthesiser

2 1 8 2

Tune

4atterie5

+asics

The GMDSS re(uires for the ships radio station among others a poer supply by arechargeable battery. Some e(uipment li$e -%Is, portable =6>+transcei!ers andS&TSF&IS+S&Ts are mainly poered by primary batteries.

Generally battery cells pro!ide electrical energy by means of an electro+chemical reactionin!ol!ing the e"change of electrons beteen the positi!e and negati!e electrodes )anodes andcathodes of the cell through an electrically conducting ion+e"change medium, in li(uid orpaste form, called the electrolyte. 'hen an e"ternal electrical load is connected current is

generated as electrons transfer from the cathode to the anode. 'hile a cell deli!ers electricalenergy, the chemical composition of the electrodes is changing. The capacity of the cell illdecrease and e!entually e"haust hen no further chemical change is possible.

1; MOD-9 CO3S- /.


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IMO


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.o%pendiu%

Figure 28 *e$d $id b$tter!

i.erent 'inds of &atteries

Generally batteries can be di!ided in to main groups?

@@ %rimary cellsFbatteries

@@ Secondary

cellsFbatteries

%rimary batteries ha!e a single lifespan, hich means that it is impossible to recharge themand therefore they re(uire periodic replacement. &lthough not rechargeable, primary batteriesha!e compensation ad!antages in se!eral applications here small si2e and long storage lifeare the main consideration. O!er the smaller range of battery si2e, the ratio poer output toeight or si2e is typically superior for primary cells.

"PS s!ste%s

>or ships8 radio stations SO9&S re(uires three independent types of poer supply?

@@ ship8s main source of energy

@@ ship8s emergency source of energy@@ reser!e source of energy )for radio stations only

In case of a brea$don of the ship8s main poer supply the ship8s emergency source ofenergy must be able to supply all important loads of the ship ith the necessary energy forthe duration of /0 hours. The emergency source of energy can consist of a self+startinggenerator or a battery.


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If the emergency source of energy is a generator it must connect automatically ith theemergency sitch board and ta$e o!er all important loads ithin ;4 seconds.


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On e!ery ship a reser!e source of energy must be a!ailable to conduct distress and safetyradio traHc in case of a brea$don of the main and the emergency source of energy for atleast one hour. To bridge the time from brea$don of ship8s main source of energy until fullacceptance of important loads by the emergency source of energy the reser!e source ofenergy ill ta$e o!er the energy supply of the radio station.

8*-*+ Characteristics of di.erent &attery types

8*-*+*1 Pri%$r!

b$tteries=in-

$rbon-ells>

>or many decades the 2inc+carbon cell as the mass mar$et primary cell. The cells consistof a 2inc co!er as the ne$tie eletrode)cathode and a bar of pressed carbon as the

positie eletrode)anode, hich is beset ith an electrolyte of an ammonium+chlorinesolution. The electric tension of one 2inc+carbon cell is /.4 =olts.

The disad!antage of 2inc+carbon cells is that they are not lea$ proof. & discharged cellelectrolyte can lea$ and hence destroy the battery contacts and printed circuit boards.

*ithiu% b$tteries>

9ithium batteries consist of an anode made of lithium and graphite and manganese dio"idecathode. Mostly

propylene carbon or acetonitrile is used as electrolyte. The cell !oltageranges from

"he advantage of secondary cell batteries over primary batteries is the ability to recharge repeatedly. "he 2'olts cell lead-acid battery has been in widespread use for more than 1, years and is still the mostcommonly used type of secondary battery on board ships. ead-acid accumulators consist of an acid-proofbody and two lead plates with the function of positive and negative electrodes. "he lead platesare beset with a + sulphuric acid (2SQ!.

Niel-Iron or Niel-.$d%iu% b$tteries>

Other types of batteries in common use in marine installation are niel-iron )Ai>e orniel-$d%iu%)AiCad batteries. These types are more robust and less dangerous thanlead batteries.

In contrast to lead batteries the electrolyte of Ai>e or AiCad does not consist of an acid butof a e batteries thepositie eletrode )anode consists of nic$el andthe ne$tie eletrode )cathode of iron plates. In AiCad batteries there are nic$el+hydro"ide+coated plates as anode and cadmium+6ydro"ide+coated plates as cathode. -achcell of both types of batteries is able to deli!er an output !oltage beteen /.< =olts and/.: =olts hen fully charged, but their output capacity increases ith temperature.

3nli$e lead batteries, Ai>e and AiCad batteries may be left discharged for a long period oftime ithout deterioration. They e"hibit a memory eectJ during the ChargeFDischargecycle and should be fully discharged before being charged or full capacity ill not beachie!ed.

*ithiu%-Ion b$tteries>

Due to further de!elopment of primary lithium cells usable rechargeable lithium+ion cells area!ailable. 9ithium+ion batteries ha!e a high energy density and no memory eect. The cell!oltage and the ma"imal charging and discharging current !ary depending on the appliedmaterials for the electrodes and the electrolyte. The durability of lithium+ion batteriesdeteriorates by employment and by time, also ithout any employment.


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.o%pendiu%

The nominal !oltage of lithium cells is appro"imately 7.E =, the charging !oltage isbeteen ;.5 = and ;.7 =. Deeply discharged batteries cause an irre!ersible damage.9ithium+ion batteries re(uire a special and complicated charging circuit.

Charging &atteries2 &attery charging methods

-"ample?

attery capacity N /;5 &h @ a!erage

To determine the state of an open lead+acid cell it is usual to ta$e readings of the speci*cgra!ity of the electrolyte by using a hydrometer. This is possible because the speci*cgra!ity rises and falls linearly during the charge and discharge process. The speci*cgra!ity of a fully charged battery diers beteen /.


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@@ note speci*c gra!ity of each cellB large !ariations beteen cells usually meanthat one or more cells no longer retain a charge and so arn of impendingfailure

@@ $eep cells8 tops clean and dry, chec$ !entilation holes, tighten terminals and coat

ith =aseline @@ ne!er put metal things on cells8 tops.

During the charging process in a lead+acid cell e"plosi!e hydrogen gas is de!eloped, hencethe need to a!oid na$ed ames or spar$s hich could cause ignition.

During use, in lead+acid batteries the ater e!aporates from the battery electrolyte. It hasto be replaced. 'hen topping up the battery cells, distilled ater has to be used to a!oidintroducing any e"traneous chemicals into the electrolyte, hich could bloc$ the chemistryof the chargingFdischarging process.

6oe!er, if in Ai>e or AiCad batteries the le!el of li(uid is reduced the cells ha!e to betopped up, not ith distilled ater but ith caustic potash.


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.o%pendiu%

Feeder

Figure 2A ;:F dipol $ntenn$

Cable

)F3-F antennas

In the M>F6> bands, hoe!er, a!elengths !ary from /05 metres )/.E45 $62 to about /, =6>, M> and 6> the *rst rule should

Li5ten


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MOD-9 CO3S- /.


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@@ > safety and health training to ensure that all cre members understand the >ha2ards and control method used.

@@ %eriodic re!ies of the program to identify and resol!e de*ciencies.

@@ &ssignment of responsibilities, including ade(uate authority and resources to

implement the program.

Non-ioniAin r$di$tions

@@ 9ocation of sources and potentially

ha2ardous area. @@ 6ealth eects and safety

standards.

@@ e(uired SPs)Standard Operating %rocedure and

control. @@ -mergency procedures.

@@ %ossible e!ents that can indicate an abnormalJ

situation? @@ 6eating of body surface

@@ aised body temperature

@@ Cummulation of charge on body surface

9*2 ./F !SC9*2*1 +asicsThe propagation of =6> transmissions is range of =6> transmissions depends in the *rstinstance on theheight also on the transmitting poer of the transmitting station. Generally it can of =6>transmissions isappro"imately 75 nautical miles. It has to be noted that the transmissions is higher thanthat of !oicetransmissions.-!ery shipborne maritime =6> transmitter its poer output beteen high poer and lopoer.The high poer output must not fall belo E 'att and not e"ceed


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/5E MOD-9 CO3S- /.


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.o%pendiu%

8 nm with 1W

30 nm with 25W

Figure +9 ,$ne o& ;:F tr$ns%issions

Figure +; ;:F h$nnellin

Duple" operation is an operating method using a to+fre(uency telecommunicationchannel in hich transmission is possible in both directions simultaneously. Channel


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MOD-9 CO3S- /.


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0se and functions of the 5-F radio station installation

Keyboard Control Menu

Buttons ButtonsDisplay

KeyboardIndicator

Lamps

Loudspeaker Squelch

Distress

Button

Figure.ontrols

!i5tre55 4uttonDThis button is protected by a lid. To use, lift the 9id and %ush thedistress button to transmit a distress alert )ithout $ind of distress.

.olumeD &d#ust the !olume.

S,uelchD %ull and ad#ust silent hen no station is recei!ed. This $nob is also to ma$e surebefore calling acoast station on a or$ing channel that there is no traHc in progress.

Control 4utton5D Control the poer )/' or unctions, etc..

&n6&G SwitchD %ush to sitch the de!ice on or o.

Loud5peakerDTo inuence the loudspea$er turn the =olume Sitch or push the rele!antControl utton.

Indicator Lamp5DThese lamps sho the condition hen lit for T @ transmitting, /' @/' transmissionmode, C&99 @ DSC announcement is recei!ed, &9&rm @ an alarm call is

recei!ed.

!i5playDThe display shos the current settings of Channel, =olume, S(uelch, Transmittingpoer, 9oudspea$ercondition, etc.

/50 MOD-9 CO3S- /.


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.o%pendiu%

Seletion o& h$nnels

To select any channel other than displayed push the number buttons 5....1, e.g. to selectchannel


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App!ica!e to

T*pe S%ips

C!ass A84

S%ips

C!ass /Coast

T0 R0 T0 R0 T0 R0/istress a!erts

"

S

/istress ac9no

"

@80=

/istress re!a* indi>idua!

"

@80=

/istress re!a* +eo+rap%ic area"

@80=

/istress re!a* a!! s%ips

"

@80=

/istress re!a* ac9noidua!

"

@80=

/istress re!a* ac9n a!! s%ips

" @80=

)r+enc* and Safet* a!! s%ips

/ll modes "

Duple* "

$edical transport

Ships and aircraft res.1!

)r+enc*8Safet* indi>idua!

/ll modes "

Duple* "

" acknowledgement Bnable to comply acknowledgement

8osition re&uest

8osition acknowledgement

"est

"est acknowledgement

Routine +roup ca!!s

/ll mode "

Duple* "

Routine indi>idua! ca!!s and t%eir ac9no


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/ll mode "

Duple* "

" acknowledgement

Data

Data acknowledgement

Bnable to comply acknowledgement

8olling

..8olling acknowledgement

Se$i8Auto ('F -optiona!

e&uest

/ble to comply acknowledgement

Start of call

Bnable to comply acknowledgement

@nd of call re&uest

@nd of call acknowledgement

H available H not available

9*2*- Operational 5-F SC procedures in the $)SS

DSC pro!ides an automated access to coast stations and ships.

The message information is stored in the recei!er and can be displayed or printed outfolloing recei!ing. >our le!els of priority @ Distress, 3rgency, Safety and outine @ area!ailable for DSC calls. &t all coast stations, ship+to+shore Distress calls recei!e priorityhandling and are routed to the nearest ,esue .oordin$tion .entre)CC. On board ship,DSC recei!ers sound an alarm hen a Distress call is recei!ed.

DSC is a techni(ue of transmitting digital codes, hich allo suitably e(uipped stationsto?

*1 Transmit and recei!e Distress alerts.

*2 Transmit and recei!e Distress alert ac$noledgements.

*+ elay Distress alerts.

*- &nnounce 3rgency and Safety calls.

*8 Initiate routine priority calls and set up or$ing channels for subse(uentgeneral communications on ,$dio 4elephon!)FT or tele".

The detailed DSC procedures are contained in the most recent !ersion ofecommendation IT3+ M 4;/.

"he detailed DSC procedures are contained in the most recent version ofecommendation 0"B- $ 71

"he only '() DSC channel is channel 3, 14%2 $(>!. /ll DSC calls automatically include phasingsignals% error- checking signals and identity $$S0 number! of the calling station. "he protocolincludes an initial do pattern% which is used to alert scanning receivers that a DSC call is imminent. therinformation can be added% either manually or automatically. "he actual information added is dependentupon the purpose of the call. "he DSC call is set up by entering information% using the command menu of

the DSC controller that is attached to% or incorporated into% the transmitter.


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9*2*-*1 1elecommand and tra/cTelecommand and traHc information important for the handling of the subse(uentinformation e"change.

9*2*-*2 Channel selection in call format

'hen calling another maritime mobile station the DSC call format should containinformation about a or$ing channel on hich both stations subse(uently e"changetheir information. On calling a coast station, do not propose a or$ing channel in theDSC announcement because the coast station ill inform each mobile station hichor$ing channel shall be used for communication ith this coast station.

9*2*-*+ SC ac'nowledgement

DSC announcements to all stations or to a certain group of stations must not beac$noledged by any of the recei!ing stations. 6oe!er, indi!idual DSC

announcements either to a coast station or another ship station should beac$noledged by the called station here!er possible.

9*2*-*- SC relay process

The only case in hich DSC information are relayed can be cases of distress.

9*2*-*8 1est transmissions

The number and duration of test transmissions shall be $ept to a minimum. They shouldbe coordinated ith a competent authority or a coast station, as necessary, and,here!er practicable, be carried out on arti*cial antennas or ith reduced poer.

6oe!er, testing on the distress and safety calling fre(uencies should be a!oided, buthere this is una!oidable, it should be indicated that these are test transmissions.

6.2.4.2. C%anne! se!ection in ca!! for$at

hen calling another maritime mobile station the DSC call format should contain information about aworking channel on which both stations subse&uently e*change their information. n calling a coaststation% do not propose a working channel in the DSC announcement because the coast station willinform each mobile station which working channel shall be used for communication with this coaststation.

6.2.4.3. /SC ac9no

DSC announcements to all stations or to a certain group of stations must not be acknowledged by anyof the receiving stations. (owever% individual DSC announcements either to a coast station or anothership station should be acknowledged by the called station where ever possible.

6.2.4.4. /SC re!a* process

"he only case in which DSC information are relayed can be cases of distress.

6.2.4.5. Test trans$issions

"he number and duration of test transmissions shall be kept to a minimum. "hey should becoordinated with a competent authority or a coast station% as necessary% and% wherever practicable%be carried out on artificial antennas or with reduced power.(owever% testing on the distress and safety calling fre&uencies should be avoided% but wherethis is unavoidable% it should be indicated that these are test transmissions.


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6.2.5. A!ertin+ and announce$ent

A!ertin+

/n alert is a digital selective call DSC! using a distress call format% in the bands used for

terrestrial radio communication% or a distress message format% in which case it is relayed throughspace stations.

"he distress alert relay is a DSC transmission on behalf of another station.

Announce$ent

/n announcement is a digital selective call using urgency% safety or routine call format in thebands used for terrestrial radio communication% or urgency% safety or routine message format% in whichcase it is relayed through space stations.

Ca!!

/ call is the initial voice or te*t procedure.

6.2.5.1. /istress a!ert

"he DSC e&uipment should be capable of being pre-set to transmit the distress alert on channel 3,.

"he distress alert shall be composed by entering the ship9s position information% the time at which itwas taken and the nature of distress. Aormally the actual ships position is taken from a suitablenavigation indicating receiver. 0f the position of the ship cannot be entered% the position informationwill be replaced as the digit E transmitted ten times. 0f the time cannot be included% then the timeinformation will be transmitted automatically as the digit repeated four times.

/ctivate the distress alert attempt by a dedicated distress button.

/ distress alert attempt will be transmitted as consecutive calls on channel 3,. "o avoid call collisionand the loss of acknowledgements% this call attempt may be transmitted on the same fre&uency againafter a random delay of between + U and 7

U min from the beginning of the initial call. "his allows acknowledgements arriving randomly to be

received without being blocked by retransmission. "he random delay will be generated automatically

for each repeated transmission; however it will be possible to override the automatic repeat manually.

"he DSC e&uipment should be capable of maintaining a reliable watch on a 27-hour basis on channel3,.

0f time permits% key in or select on the DSC e&uipment keyboard

G the nature of distress%G the ship9s last known position latitude and longitude!%

G the time in Uni)ersal *o+or$inate$ Time B"C!! the position was valid%

G type of subse&uent distress communication telephony!.

DSC /cknowledgements of distress alerts should be initiated manually. /cknowledgements shouldbe transmitted on the same fre&uency as the distress alert was received.

Distress alerts shall normally be acknowledged by DSC by appropriate coast stations only./cknowledgements by coast stations on '() will be transmitted as soon as practicable.


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"he acknowledgement of a distress alert consists of a single DSC acknowledgement which shall beaddressed to Oall shipsP and include the identification of the ship% its position and the time the positionwas valid and if possible% the nature of distress% which is being acknowledged.

0n areas where reliable communications with one or more coast stations are practicable% ship stationson receiving a distress alert or a distress call from another vessel should defer acknowledgement for ashort interval of time% so that a coast station may make the first acknowledgement.

Ships receiving a DSC distress alert from another ship should set watch on channel14 and acknowledge the call by radiotelephony when they are able to render help.

0f a ship station continues to receive a DSC distress alert on '() channel 3,% a DSCacknowledgement should be transmitted to terminate the call only after consulting with a escueCoordination Centre or a Coast Station and being directed to do so see )igure 72 (andling of areceived '() DSC distress alert!.

"he automatic repetition of a distress alert attempt should be terminated automatically onreceipt of a DSC distress acknowledgement.

/n inadvertent DSC distress alert shall be cancelled by DSC% if the DSC e&uipment is so capable.(owever in all cases% cancellations shall also be transmitted by radiotelephony.


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9*2*8*2 istress $lert rel$!

adio personnel serving on ships should be made aware of the conse&uences of transmitting a distressrelay call and of routing a DSC distress alert relay to other than coast stations CS!.

"he number of unintended activations of DSC distress alerts and DSC distress alert relays creates ane*tra work load and confusion to $!CCs and also causing delay in the response-time. "he originaldistress alert from a ship in distress should not be disrupted by other ships% by transmitting a DSCdistress alert relay.

ecommendation 0"B- $.71-E on perational procedures for the use of DSC e&uipment in the$aritime $obile Service identifies only two situations in which a ship would transmit a distress relaycall distress alert relay!

n receiving a distress alert on '() channel 3,% which is not acknowledged by a coast station

after a suitable time. "he distress alert relay should be addressed to the appropriate coast station% where

ever possible; and

n knowing that another ship in distress is not able to transmit the distress alert itself and

the master of the transmitting ship considers that further help is necessary. "he distress alert relay and

call should be addressed to Vall shipsV or to the appropriate coast station.

Bnder no circumstances is a ship permitted to transmit a DSC distress alert relay purely on receipt of aDSC distress alert on either '() or $) channels.

Ley in or select on the DSC e&uipment keyboard

Distress relay

/ll Ships or the E-digit identity of the appropriate coast station% the E-digit identity of the ship in distress% if known%

the nature of distress%

the latest position of the ship in distress% if known%

the time in B"C! the position was valid if known!%

type of subse&uent distress communication telephony!.

Coast stations% after having received and acknowledged a DSC distress alert% may if necessary%retransmit the information received as a DSC distress alert relay% addressed to all ships or a specific ship.Ships receiving a distress alert relay transmitted by a coast station shall not use DSC to acknowledgethe alert% but should acknowledge the receipt of the alert by radiotelephony on channel 14.


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3nder no circumstances is a ship permitted to transmit a DSC distress alert relay purely onreceipt of a DSC distress alert on either =6> or M> channels.

Ley in or select on the DSC e(uipment $eyboard?

@@ distress relay,

@@ all ships or the 1+digit identity of the appropriate

coast station, @@ 1+digit identity of the ship in distress, if

$non,

@@ nature of distress,

@@ latest position of the ship in distress, if

$non, @@ time )in 3TC the position as

!alid, if $non,

@@ type of subse(uent distress communication )telephony.

Coast stations, after ha!ing recei!ed and ac$noledged a DSC distress alert, may ifnecessary retransmit the information recei!ed as a DSC distress alert relay, addressed toall ships or a speci*c ship.

Ships recei!ing a distress alert relay transmitted by a coast station shall not use DSC toac$noledge the alert, but should ac$noledge the receipt of the alert by radiotelephonyon channel /E.

9*2*8*++nnoune%ents &or $ll ships (istress "ren! S$&et!)

"he announcement is carried out by transmission of a DSC urgency6safety announcement on the DSCdistress and calling channel 3,. "he DSC urgency6safety announcement may be addressed to all stationsat or to a specific station. "he channel on which the urgency6safety message will be transmitted

shall be included in the DSC urgency6safety announcement

Ley in or select on the DSC e(uipment

@@ appropriate calling format onships,

@@ category of the call )3rgencyFSafety,

@@ channel on hich the urgencyFsafety message ill be transmitted,

@@ type of communication in hich the urgencyFsafety message ill be gi!en

)radiotelephony. Transmit the DSC urgencyFsafety call.

Ship stations in receipt of an urgencyFsafety all ships announcement shall monitor the

fre(uency or channel indicated for the message for at least *!e minutes.

6oe!er, in the maritime mobile ser!ice, after the DSC announcement the urgencymessage shall be transmitted on a or$ing fre(uency?

@@ in the case of a long message or a medical callB or

@@ in areas of hea!y traHc hen the message is being repeated.

&fter the DSC announcement the safety message shall be transmitted on a or$ingchannel.

In the maritime mobile ser!ice, the safety message shall, here practicable, betransmitted on a or$ing channel. & suitable indication to this eect shall be made in theDSC announcement. In the case that no other option is practicable, the safety messagemay be sent by radiotelephony on =6> channel /E )fre(uency /4E.0 M62.

9*2*8*-+nnoune%ent to indiidu$l st$tion ("ren! S$&et! ,outine)

The =6> DSC channel :5 is used for DSC for distress and safety purposes as ell as forDSC for public correspondence.


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Ley in or select on the DSC e(uipment $eyboard for ship calling?

@@ appropriate calling format on the DSC e(uipment

)indi!idual, @@ indi!idual or group MMSI,

@@ category of the call )3rgencyFSafetyFoutine,

@@ channel on hich the urgencyFsafetyFroutine message ill be transmitted,

@@ type of communication in hich the urgencyFsafetyFroutine message ill be gi!en

)radiotelephony. Transmit the DSC urgencyFsafetyFroutine call.

& DSC announcement for an indi!idual coast station is transmitted as follos.

Ley in or select on the DSC e(uipment $eyboard?


)indi!idual, @@ indi!idual coast station MMSI,


@@ type of the subse(uent communication )normally radiotelephony

Transmit the DSC call.

/ DSC call for public correspondence may berepeated channel 3,% if no acknowledgement isreceived within min. )urther call attempts shouldbe delayed at least 1 min% if acknowledgement is stillnot received

9*2*8*8 roup $nnoune%ent

The purpose of groupannouncements could be ofinterest for that group of

Ley in or select on the DSC e(uipment$eyboard?

"he acknowledgement of a routine DSCannouncement from a coast station contains a

'() channel on which the subse&uent trafficshall be carried out


)group, @@ group MMSI,


@@ channel on hich the urgencyFsafetyFroutine message ill be transmitted,

@@ type of communication in hich the urgencyFsafetyFroutine message ill be gi!en

)radiotelephony Transmit the DSC urgencyFsafetyFroutine group announcement.

Pollin $nd position reuest

The purpose of polling

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