Which communication services are available in the Inmarsat-B system?
Distress, telephony, telex, fax, data
What is meant by "Geostationary Orbit" ?
The satellites are in an orbit 36000 km above the equator and move at the same speed as the earth
What is special about the Inmarsat-C number?
It always starts with digit 4
You have lost the signal on your Inmarsat-A terminal. All equipment appears in good working order. The ship's position is 56N, 10E. What might be the reason?
A satellite is in a blind sector
When was GMDSS globally implemented?
1st of February 1999
What is the approximate maximum range for MF telephony?
100 to 150 nautical miles
You have 2 batteries, each 12 volts, 100 A/H, connected in series. What is the combined voltage and capacity?
24 Volts, 100 A/H
What fluid is used in a lead-acid accumulator?
Sulphuric acid
What is the normal voltage of each cell in a charged lead-acid accumulator?
2 Volts
What is the unit of electrical potential? How can you be sure that your radio telex message (ARQ) is well received by the subscriber ashore?
The Volt By asking for, and receiving the answer-back from the subscriber after the message is transmitted
What is the MF DSC distress and safety frequency?
2187.5 kHz
What frequency would you use to call other vessels by the means of MF DSC? What natural phenomena is useful for propagation of high frequency (HF) radio waves? You want to call a foreign coast station on MF DSC and you do not know the national channel. What frequency would you use for transmitting and for receiving?
2177.0 kHz As few sun spots as possible Transmit on 2189.5 kHz, receive on 2177.0 kHz
In Radio Telex there are many different codes and commands in use. What does the code DER mean?
Out of order
What is the range of a VHF station especially restricted by?
Physical obstructions between transmitter and receiver.
If your vessel is "On Scene Commander" during SAR operations, how would you impose radio silence if other stations are disturbing the distress frequency? What is the average voltage across each cell in a Nickel Ferro (NiFe) accumulator when it is fully charged, and in use? You are on board the M/V Star/D5DF and have received a distress message from M/V Spiro/C6GFD. What is correct acknowledgement of this distress message? Your vessel is not under command, and you wish to warn other vessels about this. What priority would you choose?
Seelonce Mayday 1.2 Volts Mayday Spiro Spiro Spiro this is Star Star Star , Received Mayday Safety
Your EPIRB has been activated due to a mishap. You are going to cancel the alarm using Inmarsat -C. How is this done?
Type the message in the 'Editor', choose 'Transmit', then 'Distress' and then send the message accordingly
Which of these items has to be included in a distress message?
Ship's identification.
What signal can trigger a SART?
A 3 cm radar signal
What number is used to identify a vessel when alerting by means of a Cospas/Sarsat EPIRB? A Cospas/Sarsat EPIRB does not transmit the vessels position. How can the LUT (Local User Terminal) stations determine the vessels position? How many hours will the SART (Search and Rescue Radar Transponder) be able to transmit continuously when activated? What is the purpose of the mercury switch inside some types of Cospas/Sarsat EPIRBs?
The MMSI number By doppler effect 8 hours To connect the battery to the transmitter
What do the letters E.P.I.R.B. stand for?
Emergency Position Indicating Radio Beacon.
When is the telex mode FEC used?
For broadcast on NAVTEX and radio telex
Which transmission mode is used by the NAVTEX system?
F1B
What service is provided if you use the two digit code 32 on Inmarsat-B? SDR (Special Drawing Rights) is the international currency within telecommunications. How many Gold Franks are there in one SDR? How often must you prepare a technical report of the Radio Station which must be forwarded to flagstate telecom?
Medical advice 3.061 gfr Every 6 months
How often must a General Operator's Certificate (GOC) be renewed?
Every 5 years
Only one kind of EPIRB can be detected irrespective of position on the globe. What frequency does it transmit on?
406 MHz
How many NCSs (Network Control Stations) are there in the Inmarsat system? What is the MID number in the following MMSI number: 257123456? In GMDSS, there are sea areas A1, A2, A3 and A4. Which area is described as: sea area that is covered by coast stations equipped with VHF DSC?
12 257 A1
Who is responsible for the emergency radio service on board?
Any holder of GOC assigned by the master
What is the approximate range of a VHF DSC?
25 to 30 n miles
Your vessel is equipped with GMDSS for the A4 area. You are in position 76 N, 23 E, and you want to make a phone-call. What equipment would you use? What specific gravity should expect when a lead-acid battery is fully charged and in good condition?
HF Telephony 1.26 - 1.28
What is the unit of electrical current?
The Ampere
What is the average voltage across each cell of a Nickel Cadmium (NiCd) battery when it is fully charged?
1.2 Volts
Which of the following VHF channels is normally used for harbour radio traffic?
Channel 12
What is the speed of radio waves in air?
300,000 km per second
For what purpose are the following frequencies used: 2045 kHz, 2048 kHz, 2057 kHz ?
Used as ship to ship frequencies between vessels of different nationality and as working frequency to foreign coast stations
How many Hz (Hertz) are there in 1 MHz?
1,000,000 Hz
What are the channels in the international VHF channel plan?
ch 1 to 28 and 60 to 88
You want to utilise a VHF transceiver to communicate between the bridge and the poop deck. What channel and what power would you use? You have received a distress alert on MF DSC. On what frequency would you acknowledge the call if no coast station has acknowledged?
Channel 6, 1 Watt 2182 kHz
What is the Distress and Safety frequency on VHF telephony?
Channel 16
How can you avoid a false alert when cleaning certain types of Cospas/Sarsat EPIRBs with soap-water ?
The heaviest part must always point upwards and you must avoid touching the sea water contacts.
A NAVTEX message has the following ID code: LD00 (Lima Delta - Zero - Zero). What kind of message is it?
A distress (SAR) message
What priority would be appropriate to use if you want to send a Medico message on Inmarsat B? What type of radio message would you transmit if your ship has a collision and there is grave and imminent danger? A Cospas/Sarsat EPIRB is transmitting on two different frequencies. Which of the two frequencies carries the MMSI number? How many hand held VHFs must there be on board vessels greater than 500 grt?
Priority 2 Urgent Distress alert and message 406 MHz 3
How many hours will the SART (Search and Rescue Radar Transponder) be able to operate in Stand By mode?
96 hours
The Cospas/Sarsat EPIRB has global coverage. How is this possible?
Because this EPIRB utilizes satellites in low polar orbits
In the case of permanent loss of power, what type of radio message would you send?
Securite
Can MSI messages be received by equipment other than a NAVTEX receiver?
Yes, on EGC (SafetyNet) and MF/HF Radio telex
Through what equipment can you receive MSI (Maritime Safety Information) on board vessels equipped for A3?
With NAVTEX, EGC receivers and HF Radio Telex if fitted.
A vessel is equipped for A3. What distress radio equipment must be fitted if the vessel is above 500 grt? You are going to sent a radio telex through Ostende Radio in Belgium. What publication would you use to find information about frequencies to utilize for the call? What information do we need to direct the Inmarsat-A parabola antenna towards the satellite ?
1 EPIRB, 2 SARTs and 3 portable VHFs. List of Coast Stations Azimuth and elevation angles
In what ocean area do we find the AOR-E satellite?
Eastern Atlantic Ocean
Which of the following stations is, among other things, controlling the orbit of the Inmarsat satellites?
The NCS
Which areas are not covered by the Inmarsat satellites?
North of 70 degrees north and South of 70 degrees south.
A coast station has 002571234 as it's MMSI number. What is the MID number?
257
What is the main purpose of Digital Selective Calling systems?
To send and receive alerts in case of emergencies
You are radio operator on board a vessel in distress and you are 100 miles off the nearest coast station. What frequency would you use for a DSC alert?
2187.5 kHz and VHF channel 70
How many digits does a MMSI number consist of?
9 digits
How long should the radio batteries last in the GMDSS station in case of a black-out? (If the vessel is equipped with an emergency generator) What is nominal voltage for each cell of a NiFe battery during discharging?
1 hour 1.2 Volt
What radio equipment utilises the mode F1B?
Navtex/Radio Telex
What kind of gas will be developed during charging of lead acid accumulators?
Hydrogen
Which HF band would you use as "first choice" for a ship-to-shore distress alert?
8 MHz
You receive a distress alert on VHF DSC. On what channel will the following distress message be heard?
Channel 16
The wavelength of a radio signal is found by the formula: wavelength equals 300,000 divided by the frequency in kHz. What wavelength is the frequency 500 kHz?
600 meters
What mode is used for Radio Telex traffic?
F1B and FEC
What is the approximate range of NAVTEX transmissions?
200 - 400 nautical miles
HF radio communication is sometimes nearly impossible to achieve in high latitudes. What may cause this situation? A coast station has been in charge of distress traffic, and the situation is now over. What signal must the station transmit in order to lift radio silence? How many times should a Distress Call and Distress Message be repeated if no acknowledgement is received?
Too few sunspots at the time Seelonce Fini As many times as necessary
You have received a Distress Call, but the Distress Message is not heard. What would you do in this situation?
Listen in for five minutes and if nothing further is heard, inform the nearest coast station
Using spoken radio communication, what is the code word used to indicate a distress message?
MAYDAY
When an emergency is clearly over, how should a Mayday message be cancelled?
By broadcasting to all stations.
How often should the EPIRB to be tested by the vessel's crew?
Every month
How can you decide when the hydrostatic release mechanism on an EPIRB is to be replaced?
Replace the releaser according to date markings
Which frequency is used by the NAVTEX system?
518 kHz
A NAVTEX receiver can be preprogrammed in such a way that it does not receive certain messages. What messages cannot be shut out?
Meteorological warnings, navigational warnings and SAR information
How long is the Radio Safety Certificate valid prior to renewal?
5 years
How many SARTs should be carried on board?
1 set on board vessels below 500grt- 2 sets on board vessels above 500grt.
What kind of antenna is used by an Inmarsat-B terminal?
A directional antenna
With what equipment is it possible to receive EGC messages?
With Inmarsat-C only
When operating the Inmarsat-C terminal, it is not necessary to use azimuth and elevation angles to find a satellite. Why is this the case?
The Inmarsat-C terminal uses an omnidirectional antenna
What identification is used in a DSC?
MMSI number
Why are there different requirements regarding radio equipment in ocean areas A3 and A4?
Because A4 is out of range of Inmarsat satellites, and therefore makes it necessary to carry HF transceivers.
How many cells does a 12 volt lead-acid accumulator consist of?
6 cells
What is a DUPLEX radio connection?
The transmitting frequency is different from the receiving frequency
Four 12 Volt lead-acid batteries are connected in series. Each battery has a capacity of 50 Ah. How long would these batteries run a radio station that drains 10 A?
5 hours
What does the command DIRTLX mean?
Used in Radio Telex to be put in touch with a certain telex subscriber. Two way traffic.
What specific gravity would you expect from a lead acid accumulator that is fully discharged?
1.18
What is good about leading the energy from the transmitter to the antenna through a coaxial cable?
Coaxial cables are well insulated, and do not leak any energy to the surroundings.
What transmission mode would you use for HF telephony?
J3E
What do we call the special atmospheric layer that reflects high frequency (HF) radio waves? If we use Radio TELEX during On Scene Communication, the correct mode is FEC (Forward Error Correction/Broadcast). Why?
The Ionosphere Because FEC ensures that there will not be any errors in the transmissions.
In what frequency bands would you find maritime MF?
0.6 MHz to 2.8 MHz
HF (High Frequency) transmissions can have global coverage. Why?
Signals are reflected down to Earth by the Ionosphere
On what frequency bands would you expect to find maritime VHF?
150 to 180 MHz
How does the Urgency Signal sound?
Pan Pan
You have observed a drifting container in an area with heavy ship traffic. You want to warn other vessels about your observation. What signal would you use? Your propeller has dropped off in N.E. bound lane off Cap Griz Nez, Dover Strait. What priority would you choose? You have received a distress alert on MF DSC. In what circumstances should you transmit an acknowledgement by means of DSC? You have received a Distress Alert on VHF DSC channel 70. On what channel would you expect to hear the distress message? You want to transmit a Safety call on MF DSC. What frequency must be used, and on what frequency would you read the Safety Message? (It is not a vital message) Which of the following modes would be appropriate to use for receiving radio telex on MF/HF? The Cospas/Sarsat EPIRB transmits on two frequencies. Why does it transmit on 121.5 MHz? Only one kind of EPIRB can be detected anywhere on the globe. What frequency is used for detection and to find the position of the EPIRB? How long a time will the battery in a Cospas/Sarsat EPIRB last when activated? How often should the EPIRB hydrostatic release mechanism be replaced? If you are in a position outside the coverage area of Inmarsat satellites; what equipment could you use to receive MSI (Maritime Safety Information) traffic? What kind of messages are received by a NAVTEX receiver? You have had a radio telephone call through Singapore Radio. Total charge for the call was 30.61 Gold Franks. How many SDR (Special Drawing Rights) does this amount to? What radio communications must be entered into the Radio Log Book? What radio equipment would you expect to find on board a vessel above 500 grt in sea area A1?
SECURITE Urgency If the station in distress is near your position and no coast station has acknowledged the alert Channel 16 Transmit call on 2187.5 kHz, read the message on 2182.0 kHz. F1B To give the homing signal during SAR operations 406 MHz 48 hours According to the date label A NAVTEX receiver and HF radiotelex MSI messages 10 SDR Only distress and urgency communications 1 EPIRB, 2 SARTs, 3 portable VHFs, NAVTEX receiver, 1 VHF with DSC.
What service is provided if you use the two digit code 00 on Inmarsat-B? You are in position 20 N and 179 E. You wish to switch on the Inmarsat A terminal. Which Inmarsat satellite would you have to use in this part of the globe? Your vessel has rudder failure, and is adrift in an area with heavy traffic. What priority would be appropriate to use if you want to notify shipping around you about this danger? During distress traffic, the vessel in distress is disturbed by other stations on 2182 kHz. What message should this vessel transmit to impose radio silence? Ocean area A2 is described as an.... Why does the SART (Search & Rescue Radar Transponder) scan from 9.2 to 9.5 GHz in the X band? You are radio operator on board a vessel in distress. The nearest coast station is 100 miles away. If you want to transmit the alert on DSC, what frequency(s) would you use? You have received a distress alert on HF DSC. No acknowledgement is received from a coast station. What would you do next? What radio transceivers may normally be used when the vessel is in port?
Automatic telephone service Pacific Ocean Region - POR Urgency Seelonce Mayday Ocean area covered by coast stations equipped with MF DSC. All 3 cm radars are preprogrammed to transmit on a specially allotted frequency within the X band. 2187.5 kHz and Channel 70 Transmit Distress Relay to the nearest coast station. Inmarsat systems and VHF transceiver
Two channels on VHF have limited output (1 watt). Which are they?
Channels 15 and 17
How do we find out if a NiCd accumulator is fully charged?
Measure the voltage during charging
Why is the radiation from a transmitting antenna weaker if the insulators are covered with soot and salt?
Because soot and salt would lead the antenna current to ground.
What is the correct charging voltage of a 12 Volt lead battery?
12 Volts
What mode(s) is allowed on 2182 kHz?
H3E and J3E
What mode(s) is allowed on HF telephony?
J3E only
Why are the VHF antennas much smaller than MF/HF antennas?
Because VHF is operating on high frequencies and thereby has a short wave-length
What does the acronym ARQ mean?
Automatic Repetition Request
On what frequency bands would you expect to find maritime HF?
4000 to 25000 kHz
What is the main difference between FEC (Forward Error Correction) and ARQ (Automatic Retransmission Request) used in radio telex systems?
ARQ is a two way connection in a private circuit (Ship - Shore or Ship - Ship) while FEC is used solely for broadcast.
Which station should primarily lead the distress traffic?
Always a coast station
You have received a distress alert on HF DSC. What would you do next?
If no acknowledgement is received from a coast station, transmit a Distress Relay
How can you test the Distress Alert capability in the Inmarsat-C system? You want to transmit an Urgency call on MF DSC. On what frequency would you send the call, and on what frequency would you read the message?
By activating the 'Link Test' Send call on 2187.5 kHz, read the message on 2182 kHz.
What command would be appropriate to use if you want to be connected directly to a subscriber via radio telex?
DIRTLX....+
How accurate is the positioning of a Cospas/Sarsat EPIRB?
Within a radius of 5 km
What is the approximate range of a SART?
5 - 10 n. miles
What is a SART?
Search And Rescue Transponder.
What is an EPIRB?
An electronic emergency position-indicating radio beacon.
How many NAVAREAs are there in the world?
16
EGC consists of SafetyNet and FleetNet. What services do we get from FleetNet?
Commercial information for subscribers only
What type of radio messages contain important navigational or meteorological warnings?
safety
How is Inmarsat-C traffic charged?
By k Bit (kilobits)
In what publication would you find information about times and frequencies for traffic lists?
List of Coast Stations
How many portable SAR VHFs must be carried on board vessels?
2 sets on board vessels below 500 gr, Tons, - 3 sets on board vessels above 500 gr. Tons.
