1. Chapter 6: MARITIME SAFETY INFORMATION (MSI) UNDER THE GMDSS MSI is defined in general terms as "navigational and meteorological forecasts, and other urgent safety-related messages", of vital importance to all ships at sea. The categories of MSI under the GMDSS have expanded considerably, in keeping up with the requirements of world shipping and the capabilities of new technology. The new developments have offered the greatest potential benefit and improvement in safety services for all ships. There are seven basic categories of MSI within the GMDSS:
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2. • Navigational warnings; • Meteorological warnings; • Ice reports; • Search and rescue information; • Meteorological forecasts; • Pilot service messages; • Electronic navigational systems update messages.
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3. Prior to the GMDSS, in order to receive all necessary messages in the above categories, operators would require the broadcast times and frequencies of the numerous radio stations and take time to copy each relevant broadcast. Under the GMDSS, a ship anywhere in the world should be able to receive all types of information by just flipping the switch of two small receivers.
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4. The MSI service is an internationally coordinated network of broadcasts of Maritime Safety Information from different Information Providers, such as: • National Hydrographic Offices, for navigational warnings and electronic chart correction; • National Meteorological Offices, for weather warnings and forecasts; • Rescue Co-ordination Centres, for shore-to-ship distress alerts, and other urgent information; • International Ice Patrol, for North Atlantic Ice hazards. Only Information Providers approved by the IMO, the IHO or the WMO are given the authorization to make MSI broadcasts.
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5. Two Independent Systems for Broadcasting MSI The GMDSS supports two independent systems for broadcasting MSI: • The International NAVTEX Service, whereby the Information Provider forwards the MSI for a given area to a 518 kHz MF NAVTEX transmitter; note that reception of NAVTEX MSI is limited by the range of the MF transmitter to the coastal area immediately around the transmitter; • The International SafetyNET Service, whereby the Information Provider forwards the MSI for a given area to an Inmarsat Coast Earth Station (CES), for broadcasting via the satellite network over an entire Inmarsat Ocean Region; consequently, ships can receive SafetyNET MSI anywhere in that Ocean Region, irrespective of their distance from the CES / Information Provider.
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7. MSI for a given area is generally broadcast over either NAVTEX or SafetyNET (except for some exceptional circumstances where a message may be broadcast using both services); ships equipped with both a NAVTEX receiver and SafetyNET receiver should select the appropriate receiver to receive MSI for the area in which the ship is operating. Where a coastal area is not covered by the International NAVTEX service, for example around Australia, MSI for that area will be broadcast on SafetyNET.
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8. Scheduled and Unscheduled MSI Broadcasts To ensure that the user knows when to receive MSI for a given area and subject, many MSI broadcasts are scheduled, under IMO coordination, to a particular time, via CES and satellite. For example, all navigational warnings and meteorological forecasts are scheduled broadcasts (and given Safety priority, which does not produce an alarm at the terminal when received), while meteorological warnings and distress alerts are unscheduled broadcasts (and given urgent or distress priority, which produces an alarm at the terminal).
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9. To be sure of receiving a scheduled MSI broadcast, the receiver must be tuned to the appropriate channel / satellite at the specified time, and programmed to receive information for the area concerned. A smaller number of MSI messages are transmitted as unscheduled broadcasts, for example urgent navigational warnings, severe weather warnings, and distress alert relays. Unscheduled SafetyNET broadcasts are made over all satellites covering an area, so the receiver will not miss the message, no matter what satellite it is logged-in to. The user is advised of the receipt of an unscheduled broadcast by the terminal giving an alarm.
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10. Language Used for MSI Broadcasts All MSI broadcasts made on the International MSI service are printed in the English language (sometimes a local language is added after the English wording).
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11. 6.1.5 NAVAREAs / METAREAs The 16 Navigational Areas (NAVAREAs), which are the same as the Meteorological Areas (METAREAs), into which the earth's navigable waters are sub-divided for the purpose of SafetyNET broadcasts are depicted in this Chapter. For each area, a NAVAREA Coordinator co-ordinates the broadcasting of navigational warnings, and a Meteorological Issuing Service co-ordinates the meteorological information throughout that area.
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13. 6. 1. 5. 1 The IHO/IMO WWNWS Services 6. 1. 5. 1
The IHO/IMO WWNWS Services Introduction of WWNWS The World Wide Navigational Warning Service (WWNWS) is a coordinated global service for the broadcast by radio of vital information on hazards to marine navigation. For purposes of the Service, the world has been divided into 16 "NAVAREAS". Within each NAVAREA one national authority, designated the Area Coordinator, has assumed responsibility for the coordination and promulgation of warning. Designated "National Coordinators" of the other coast states in a NAVAREA are responsible for collecting and forwarding information to the Area Coordinator.
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14. The WWNWS establishes three types of navigation warning, as follows: (1) NAVAREA Warnings generally concern information required by ocean-going mariners in offshore waters. This includes the failure of important aids to navigation and other information which may affect planned navigational routes. (2) Coast Warnings promulgate information which is necessary for safety in coastal waters. (3) Local Warnings giving detailed information within the limits of a harbour or port authority on aspects which the ocean-going ship does not normally require. Local warnings are normally broadcast on VHF voice only.
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15. Meteorological Warnings and Forecasts Meteorological services will be provided under a new system of international coordination and co­operation , similar to the World Wide Navigational Warning Service, currently being developed by the World Meteorological Organization (WMO) in Geneva.
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16. SOLAS Requirements for Receiving MSI Broadcasts Every SOLAS-compliant ship must meet the following legal requirements for receiving MSI broadcasts: • Watch-keeping - every ship, while at sea, shall maintain a radio watch for broadcasts of Maritime Safety Information on the appropriate frequency or frequencies on which such information is broadcast for the area in which the ship is navigating. • Logging Messages - on a SOLAS-compliant ship, a written record shall be Kept in the radio log of the time and identity of all safety messages received. A printed copy shall be kept of the text of all distress traffic. In addition to these mandatory requirements, IMO recommends that all current navigational and meteorological messages be retained on the bridge, for as long as they are applicable, for the use of the person in charge of the navigational watch.
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17. 6.2 The Inmarsat Enhanced Group Call (EGC) Services The Inmarsat-C satellite communications system has a capability known as Enhanced Group Call (EGC), which enables Information Providers to send messages for selective reception by EGC receivers located anywhere in the four Ocean Regions. The Information Provider determines which receivers are to receive the message by including identifying information, such as the NAVAREA / METAREA / geographical area for which the MSI is intended, along with the message; individual EGC receivers can be programmed to use this information to select only the required messages, and to reject all others. Based on this selective capability, the EGC system supports two services:
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18. • The EGC SafetyNET Service, which allows the EGC receiver operator to program the receiver with the geographical areas for which MSI will be received, and the categories of MSI messages required. • The EGC FleetNET Service, a commercial service, where individual EGC receivers are programmed to store an EGC identification (ENID) code, which is used to select only messages intended for ships belonging to a group, such as a fleet or national flag, or subscribers to an information service.
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20. General Features of the EGC System INMARSAT'S EGC system is part of the INMARSAT-C system and is complementary to the international NAVTEX service. The EGC services include: • SafetyNET - for promulgation of MSI; and • FleetNET - for transmission of fleet management and general public information to fleets or groups of ships. It is a feature of satellite communications that reception is not generally affected by the position of the ship within the ocean region, atmospheric conditions or time of day. EGC messages can be addressed either to geographical areas (area call) or to groups of ships (group calls): (a)        Area calls can be to a fixed geographical area, such as one of the 16 NAVAREAS, or to a temporary geographical area selected by the originator. Area calls will be received automatically by any ship whose receiver has been set to one or more fixed areas or recognizes a temporary area by the geographic position. (b)        Group calls will be received automatically by any ship whose receiver acknowledges the unique group identity associated with a particular message.
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21. 6.3 SAFETYNET
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28. Availability of MSI in different areas To avoid excessive duplication of broadcasts, the IMO has authorised the following arrangements: For a given NAVAREA/METAREA which is covered by more than one Ocean Region satellite, scheduled broadcasts of MSI, such as navigational warnings and meteorological information, are made only via a single nominated satellite/Ocean Region. For a NAVAREA/METAREA which is covered by more than one Ocean Region satellite, unscheduled broadcasts of MSI, such as gale warnings and distress alert relays, are made via all satellites/Ocean Regions which cover the area concerned.
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29. Requirements for receiving Safety NET MSI broadcasts For a ship to be able to receive SafetyNET MSI broadcasts, certain technical and legal requirements must be met • The ship must be equipped with a type-approved EGG receiver - this may be a standalone EGC receiver, or a receiver combined with an Inmarsat SES. • For optimal performance and GMDSS certification, the EGC receiver / SES should be installed in the vessel in accordance with the Design and Installation Guidelines, available from Inmarsat. • For the ship to be certificated in the GMDSS, the installation must comply with the GMDSS requirements of the national administration for the country in which the vessel is registered.
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30. • The SES with EGC receive capability must be commissioned into the Inmarsat system • The EGC receiver / SES must be set-up as indicated in the manufacturer's instructions - this includes ensuring that the receiver / SES is tuned (synchronized) to the NCS Common Signalling Channel. • The printer and any other peripherals connected to the receiver / SES must be made ready as indicated in their manufacturer's instructions.  
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31. Repeat broadcasts of MSI information Some classes of EGC receivers/SESs may not provide uninterrupted monitoring of the channel used for MSI broadcasts, and may switch to a different channel for normal commercial traffic. To improve the probability of these receivers receiving MSI broadcasts, Information Providers re-broadcast some messages: Unscheduled messages, such as distress alerts and gale warnings are re-broadcast six minutes after the initial broadcast; Scheduled broadcasts, such as navigational warnings and other longer-term information are repeated at every scheduled time, for as long as they remain in force. (Repeated broadcasts of the same message may, however, give some users the problem of receiving too many printed messages - for advice, see the section Printing only essential messages.)
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32. 6.3.6 Typical MSI broadcasts
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33. EGC receiver management The section should be read in conjunction with the manufacturer's instructions, for specific information on how to do the following: Select a satellite/Ocean Region; Program the receiver for specific NAVAREAs / METAREAs for which to print messages; Update the receiver regularly with the ship's position; Specify the additional types of MSI message required; Tune in at the scheduled times of MSI broadcasts.
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34. Selective message reception Although an EGC receiver will receive and can print all SafetyNET broadcasts made throughout an entire Ocean Region, many messages may not be useful to the ship - for example those applicable to NAVAREAs beyond the ship's planned voyage, or those on subjects not relevant to the ship's circumstances. To avoid a receiver printing a large number of unnecessary messages, it can be programmed to print only essential messages, and to reject all other messages - every receiver is supplied with software which stores the geographical boundaries of the NAVAREAs; the receiver can use this information to print only those messages applicable to the current area, plus any other areas programmed by the operator. (Note, however, that the receiver cannot be programmed to reject "all ship" messages, such as some shore-to-ship distress alerts and Met/Nav warnings.) The receiver examines the message handling instructions (the "C" codes) included with each message, and uses this information to decide which messages to print. Similarly, the receiver stores the unique number included with each message, and uses this to avoid printing extra copies of those messages already received and printed correctly.
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35. Regular position updates Your EGC receiver MUST be updated regularly with the ship's position. The reasons for updating your EGC receiver regularly with the ship's position include: To decide if the receiver should print a message which it has received addressed to a specific geographic area; To print only messages for the required areas - if the ship's position has not been updated for 12 or 24 hours (depending on the model), the receiver will automatically print or store all geographically addressed messages within the entire Ocean Region; Another important reason for updating the terminal regularly with the ship's position, while not directly related to the SafetyNET service, is to ensure that the correct position is given if a distress alert has to be sent.
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36. Two ways are available to update a terminal with the ship's position: 1. Automatically, using an electronic navigational device; the use of a GPS (Global Positioning System) receiver to provide position updates is highly recommended because of its accuracy and reliability. Some SES models can be purchased with an integral GPS receiver, whilst others can be interconnected with a separate on-board GPS receiver Manually, by keying the position co-ordinates directly into the terminal; IMO requires this be done every four hours. It is strongly recommended that automatic position updating is used whenever available.
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37. NAVTEX NAVTEX is an international automated narrow band direct-printing service for promulgation of navigational and meteorological warnings and urgent information to ships. It has been developed to provide a low cost, simple and automated means of receiving maritime safety information on board ships at sea, especially in coastal waters. The information transmitted is relevant to all sizes and types of vessel and the selective message-rejection feature ensures that every mariner can receive a safety information broadcast which is tailored to his particular needs.
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38. Definitions (a)   NAVTEX means the system for the broadcast and automatic reception of maritime safety information by means of narrow-band direct-printing telegraphy. (b)   International NAVTEX service means the coordinated broadcast and automatic reception on the frequency 518 kHz of maritime safety information by means of narrow-band direct-printing telegraphy using the English language. (c) National NAVTEX services means the broadcast and automatic reception of maritime safety information by means of narrow-band direct-printing telegraphy using frequencies other than 518 kHz and languages decided by the Administrations concerned.
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39. Principal features of NAVTEX The service uses a single frequency with transmissions from nominated stations within each NAVAREA / METAREA being arranged on a time-sharing basis to eliminate mutual interference. All necessary information is contained in each transmission. The power of each transmitter is regulated so as to avoid the possibility of interference between transmitters. This is particularly important during night-time hours, as Medium Frequencies always travel further after dark.
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41. Shipboard NAVTEX EQUIPMENT A NAVTEX receiver is normally a compact unit, with an integrated printer, display and keyboard. Once programmed with appropriate station codes and subject indicator characters, the unit is left unattended - messages are received automatically and printed on the integrated printer.
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42. A dedicated NAVTEX receiver which has the ability to select messages to be printed, according to: (a) a technical code (B1, B2,B3,B4). which appears in the preamble of each message; and (b) whether or not the particular message has already been printed. Certain essential classes of safety information such as navigational and meteorological warnings and search and rescue information are non-rejectable to ensure that ships using NAVTEX always receive the most vital information. NAVTEX coordinators exercise control of messages transmitted by each station according to the information contained in each message and the geographical coverage required. Thus a user may choose to accept messages either from the single transmitter which serves the sea area around his position, or from a number of transmitters as appropriate.
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44. MESSAGE PRIORITIES Three message priorities are used to dictate the timing of the first broadcast of a new warning in the NAVTEX service In descending order of urgency they are: VITAL — for immediate broadcast, subject to avoiding interference to ongoing transmissions; IMPORTANT — for broadcast at the next available period when the frequency is unused; ROUTINE — for broadcast at the next scheduled transmission period   Note: Both VITAL and IMPORTANT warnings will normally be repeated, if still valid, at the next scheduled transmission period.
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46. ZCZC defines the end of the phasing period, the B1 character is a letter (A-Z) identifying the transmitter coverage area, the B2 character is a letter (A-Z) for each type of message. B3B4 is a two-character serial number for each message, starting with 01 except in special cases where the serial number 00 is used. The transmitter identification character (B1) is a single letter allocated to each NAVTEX shore station transmitter. NAVTEX receivers allow the operator to accept or reject messages from any station, based on this single letter code. The subject indicator character (B2) is also single letter code which serves to identify the message subject. NAVTEX receivers also allow the operator to reject certain messages based on the subject indicator character. However, messages concerning Navigational Warnings, Meteorological Warnings, and Search And Rescue information can not be rejected.
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47. THE TRANSMITTER IDENTIFICATION CHARACTER (B1) In order to avoid erroneous reception of transmissions from two stations having the same B1 character, it is necessary to ensure that such stations have a large geographical separation. This is achieved by allocating B1 characters in line with the general global scheme which shows the IMO-adopted strategy for allocating B1 characters by alphabetical sequence through each NAVAREA / METAREA of the World-Wide Navigational Warning Service. NAVTEX transmissions have a designed maximum range of about 400 nautical miles. The minimum distance between two transmitters with the same B1 identifier is usually sufficient to ensure that a receiver cannot be within range of both at the same time.
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48. SUBJECT INDICATOR CHARACTERS (B2) Information is grouped by subject on the NAVTEX broadcast, and each subject group is allocated a subject indicator character B2. The subject indicator character is used by the receiver to identify different classes of messages. The indicator is also used to reject messages concerning certain optional subjects which are not required by the ship. For example, LORAN messages might be rejected in a ship which is not fitted with an LORAN receiver. Receivers also use the B2 character to identify messages which, because of their importance, may not be rejected.
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49. Subject indicator characters assigned to the NAVTEX system are as follows: A - Navigational warnings B - Meteorological warnings C - Ice reports D - Search and rescue information E - Meteorological forecasts F - Pilot service messages G - Decca messages H - Loran messages I -  Omega messages J - Satnav messages K - Other electronic navaid messages L - Additional navigational messages V - Special services W - Special services (possible other languages use) X - Special services Y- Special services Z - No message on hand (QRU)
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50. 6.4.5 MESSAGE NUMBERING (B3 B4) Each message within a subject group is allocated a serial number, B3 B4, between 01 and 99. On reaching 99, numbering will re-commence at 01 but avoiding the use of message numbers still in force. A shortage of numbers will, where possible, be alleviated by the allocation of messages to other, relevant subject groups. It has been found that 99 messages are not always enough for some subject groups, and B2 = L may be used for additional navigational warnings, to receive the overflow from B2 = A when necessary. While B3B4 is allocated 00, it means that this message is vital and cannot be rejected by NAVTEX receiver, which is related to the very important SAR or distress alert relay information generally.
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51. Allocation of transmission times In order to ensure the least possible interference between transmitting stations, the transmitting schedules must take account of the relative geographical location of all stations within range. Figure 36 illustrates a basic organizational matrix which may be used by the IMO Coordinating Panel on NAVTEX to evaluate and recommend time schedules for each transmitter of a proposed new service. The table shows the breakdown of a representative NAVAREA into four groups of transmitters. Each group has a potential of six transmitters, each with a 10 minute allocated transmission time every 4 hours.
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53. Exercises: Frequencies for receiving MSI (Maritime safety information) are: A. MF SSB frequencies specified for MSI. B. HF SSB frequencies specified for MSI. C. MF NBDP frequencies specified for MSI. D. HF NBDP frequencies specified for MSI. Which of the following is the primary international NAVTEX frequency? A kHz B kHz C. VHF Channel D. 518 kHz. What means is used to avoid mutual interference by stations in the NAVTEX system? A. Transmitter power is limited to that necessary for coverage of assigned area and transmissions by stations in each NAVAREA are arranged in a time-sharing basis. B. Transmissions by stations in each NAVAREA are arranged in a time-sharing basis. C. Transmitter power is limited to that necessary for coverage of assigned area. D. Stations are limited to daytime operation only.
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54. Which determines whether a NAVTEX receiver rejects a particular type of message content? A. The subject indicator matches that programmed for rejection by the operator B. All of these. C. The serial number and type of message have already been received. D. The transmitting station ID covering your area has not been programmed for rejection by the operator. Should too many errors occur in a received NAVTEX message: A. The NAVTEX receiver requests retransmission of the message. B. The messages are automatically retransmitted once, and possibly more, depending on their level of importance. C. The message is lost. D. The NAVTEX receiver will select another transmitting station.
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55. Areas referred to by NAVTEX are the same as: A. INMARSAT ocean regions
Areas referred to by NAVTEX are the same as: A. INMARSAT ocean regions. B. WWNWS (World-wide Navigational Warning Service) areas. C. MRCC (Maritime Rescue Coordination Center) regions. D. GMDSS sea areas. Which statement is NOT true regarding the NAVTEX system? A. A selective message-rejection feature of the receiver allows the mariner to receive only that safety information pertinent to his requirements. B. NAVTEX carries routine meteorological forecasts and warnings and other urgent safety information to ships. C. NAVTEX carries information relevant to all sizes and types of vessels within a region established for this service. D. NAVTEX is tailored for international sea commerce on or near main shipping lanes.
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56. A ship operating in an area not covered by NAVTEX: A
A ship operating in an area not covered by NAVTEX: A. Is exempt from copying MSI if they are using an automated chart correction system and guard kHz. B. Is exempt from copying MSI (Maritime safety information). C. Must be capable of receiving MSI via HF NBDP or INMARSAT-A. D. Must be capable of receiving MSI via HF NBDP or INMARSAT-C. Which message subject matter cannot be disabled by the operator of a NAVTEX receiver? A. All of the following. B. Navigational warnings. C. Meteorological warnings. D. Search and Rescue information.
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57. NAVTEX broadcasts are sent: A
NAVTEX broadcasts are sent: A. Regularly after the radiotelephone silent periods. B. On request of maritime mobile stations. C. Immediately following traffic lists. D. In categories of messages indicated by a single letter or identifier. Which message subject matter can be programmed to be rejected or disabled by the operator of a NAVTEX receiver? A. Navigational warnings. B. Meteorological warnings. C. All of these. D. Pilot Service Messages.
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58. Which information determines if a NAVTEX message is to be rejected. A
Which information determines if a NAVTEX message is to be rejected? A. The Answerback of the receiving station has not been entered in the NAVTEX receiver. B. Transmitter identity (numerals from 1 to 26 identifying transmitting station within the NAVAREA). C. Only messages having a serial number 00 are rejected. D. Subject indicator (single letter from A to Z indicating the type of message). What happens when the storage memory capacity of the NAVTEX receiver is exceeded? A. The unit becomes inoperative until files are manually deleted by the operator. B. The oldest ID is automatically erased and if the message is still being transmitted it is received again. * C. An alarm is sounded until the operator clears the memory of stored data. D. The text is printed but not stored until the operator manually deletes message files.
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59. The term "MSI" normally refers to: A
The term "MSI" normally refers to: A. Maritime Safety Information broadcasts using NBDP TELEX on designated HF frequencies in FEC (forward error correction). B. Maritime Safety Information broadcasts using NBDP TELEX on designated HF frequencies in ARQ. C. None of these. D. Maritime Safety Information broadcasts using HF voice (J3E) for those who are not equipped with NBDP TELEX or NAVTEX. NAVTEX transmitters have a range of: A nautical miles ( km) from shore. B nautical miles ( km) from shore. C nautical miles ( km) from shore. D. 30 nautical miles (56 km) from shore.
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60. Which is a correct statement regarding NAVTEX message format. A
Which is a correct statement regarding NAVTEX message format? A. Subject or type of message is indicated using numbers from 01 to 99. B. None of these. C. Transmitter identity is indicated by a single letter from A to Z. D. Date and time is used in-lieu-of message serial numbers. What means are used to prevent the reception of unwanted broadcasts by vessels utilizing the NAVTEX system? A. Operating the receiver only during daytime hours. B. Programming the receiver to reject unwanted broadcasts. C. Coordinating reception with published broadcast schedules. D. Automatic receiver de-sensitization during night hours.
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