A
299. INMARSAT-C provides for which of the following?
A. Polling, enhanced group call, one-way position and data reporting via satellite. B. FM voice communications via satellite.
C. Two-way messaging and data communication on a store-and-forward basis.
D. Polling, enhanced group call, one-way position and data reporting via satellite, two-way messaging and data communications on a store-and-forward basis.
D
300. Which of the following is not true about INMARSAT-F? A. Provides high-quality FM voice communications. B. Provides high-speed data communications. C. Requires a stabilized, directional antenna.
D. Is capable of receiving Enhanced Group Call broadcasts without the addition of a separate calss-2 receiver.
D
第四章 常规通信 301. What statement best describes demodulation?
A. Detuning the receiver to remove interfering signals. B. Removing atmospheric noise from the signal.
C. Removing the information signal from the carrier. D. Separating the telex signals from the voice signals.
C
302. How many sidebands are present in a standard A.M. signal? A. One B. Two C. Three D. Four C
303. Which of the following statements concerning DSC equipment is true?
A. The GMDSS operator is responsible for proper selecting of HF DSC guard channels. B. All equipment must be type accepted.
C. The vessel’s navigational position must be updated, either automatically or manually, no less often that every four (4) hours.
D. All of these. D
304. Which of the following is not a DSC watch frequency?
A. 2187.5 KHz B. 2182 KHz C. 12577 KHz D. 6312 KHz B
305. Which frequency is designated for VHF Digital Selective Calling?
A. 156.300 MHz B. 156.650 MHz C. 156.800 MHz D. 156.525 MHz D
306. Which channel is designated for VHF Digital Selective Calling?
A. Channel 06 B. Channel 13 C. Channel 16 D. Channel 70 D
307. What is defined as an area, excluding sea area A1, within the radiotelephone coverage area of at least on MF coast station, in which continuous DSC alerting is available as defined by the IMO?
A. Sea Area A4 B. Sea Area A3 C. Sea Area A2 D. Ocean Area Regions AOR-E, AOR-W, POR or IOR.
C
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308. What is defined as an area, excluding sea areas A1 and A2, within the coverage of an INMARSAT geostationary satellite in which continuous alerting is available?
A. Sea Area A3 B. Ocean Area Region AOR-E, AOR-W, POR or IOR C. Sea Area A4 D. Coastal and Inland Waters
A
309. What is the requirement(s) of the DSC equipment for GMDSS equipped vessels? A. HF DSC guard channels must be properly selected. B. Must be type approved by the administration concerned.
C. The ship’s navigation position must be entered by Electronic navigation equipment while she ship is underway.
D. All of these. D
310. Which channel is designated for GMDSS Digital Selective Calling in general services?
A. Channel 06 (156.300 MHz) B. Channel 13 (156.650 MHz) C. Channel 16 (156.800 MHz) D. Channel 70 (156.525 MHz)
D
311. What unit may consist of a modem, a signal coder/decoder and a central processor unit for creating the different call formats, etc?
A. NBDP ARQ modem B. DSC Control unit. C. Ship Earth Station B.D.E. Unit. D. Personal Computer unit
B
312. What does a DSC control unit do when a DSC message is received?
A. When receiving DSC message other than a distress, urgency and safety call, the control unit is able to provide for an automatic transmission acknowledging the call received.
B. The information contained in the DSC message is decoded and displayed on the front panel. C. The information may be stored in an internal memory. D. All of these D
313. What does a DSC control unit do when a DSC message is received?
A. When receiving DSC message other than a distress, urgency and safety call, the control unit is able to provide for an automatic transmission acknowledging the call received.
B. The information contained in the DSC message is decoded and displayed on the front panel and may be stored in an internal memory.
C. An audio alarm sounds when a DSC message is received. D. All of these D
314. What signal is used to allow a scanning receiver to stop and detect an MF or HF DSC distress message? A. A two-tone alarm code is received.
B. A series of four-second dashes are received. C. a 200-bit 100-baud dot pattern is received.
D. A steady audio alarm is received, allowing the operator to select the desired frequency for the reception of the message.
C
315. Which frequency is used for inter-ship DSC calling purposes?
A. 2177 KHz B. Both 2177 KHz and 156.525 MHz. C. 156.525 MHz D. 2177 KHz and 2189.5 KHz used in pairs.
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B
316. Which frequency can be used for routing DSC calling between ships and shore? A. 2177 KHz B. 2177 KHz and 2189.5 KHz used in pairs.
C. 156.525 MHz D. Both 2177 KHz/2177 KHz and 2177 KHz/2189.5 KHz used in pairs. D
317. What is the emission designation for VHF-FM? A. F3C B. J2B C. G3E D. J1B C
318. What is the emission designation for MF/HF voice signals? A. F1B B. J3E C. J2B D. F3E B
319. In a properly functioning MF/HF DSC system, the receiver bandwidth should be: A. 300 Hz maximum B. Sufficiently wide to pass video pulses.
C. 1.7 KHz D. As narrow as possible, but not less than 170 Hz. A
320. A properly operating MF/HF DSC transmitter used in the GMDSS system can be expected to have a carrier frequency accuracy of:
A. +/- 10 Hertz Coastal, +/- 25 Hertz Marine B. +/- 10 Hertz Coastal and Marine C. +/- 25 Hertz Coastal and Marine D. +/- 100 Hertz Coastal and Marine B
321. What is the purpose of a DSC control unit?
A. It decodes and displays the message. B. It will store the message internally until manually retrieved.
C. In some circumstances, it will automatically acknowledge routine DSC calls. D. All of these.
D
322. When operating in coastal waters (sea area A1), a GMDSS-equipped vessel must:
A. Maintain a continuous DSC watch on 8514.5 KHz. B. Maintain a continuous aural watch on 2182 KHz
C. Maintain a continuous DSC watch on channel 16. D. Maintain a continuous DSC watch on channel 70.
D
323. A GMDSS-equipped vessel must carry equipment capable of Medium Frequency (MF) DSC transmission and reception:
A. When operating in areas of no INMARSAT coverage. B. When operating outside of VHF-DSC range of shore.
C. Only if not equipped with the Enhanced Group Call system. D. In all operating ocean areas. B
324. DSC is used primarily to:
A. Transmit and receive distress and safety alerts to and from other ships and shore stations via radio. B. Receive weather warnings, navigational notices and other marine safety information. C. Provide routine communications with the ship owner.
D. Report ship’s position to search-and-rescue authorities via satellite. A
325. On VHF band, DSC installations:
A. Should be tested daily with radiation of signals. B. Should be tested weekly with radiation of
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signals.
C. should be tested monthly with radiation of signals. D. Should be test without radiation of signals. D
326. If a ship, in accordance with the requirements of regulation 7.1.2 (of the amendments to the 1974 SOLAS convention), is fitted with a VHF radio installation, while at sea, shall:
A. Maintain a watch on Channel 70.
B. Maintain a continuous watch on Channel 70.
C. Maintain a continuous watch on Channel 16 manually, because the DSC watch-keeping is performed automatically.
D. Maintain a continuous watch on 2174.5 KHz. B
327. If a ship, in accordance with the requirements of regulation 9.1.2 or 10.1.3 (of the amendments to the 1974 SOLAS convention), is fitted with a MF radio installation, while at sea, shall:
A. Maintain a watch on 2174.5 KHz.
B. Maintain a continuous watch on Channel 70.
C. Maintain a continuous watch on 2182 KHz manually, because the DSC watch-keeping is performed automatically.
D. Maintain a continuous watch on 2187.5 KHz. D
328. If a ship, in accordance with the requirements of regulation 10.2.2 or 11.1 (of the amendments to the 1974 SOLAS convention), is fitted with an M/HF radio installation, while at sea, shall:
A. Maintain a watch on 8414.5 KHz.
B. Maintain a continuous watch on at least one of the following HF DSC frequencies: 4207.5 KHz, 6312, 12577 or 16804.5 KHz.
C. Maintain a continuous watch on 2187.5 KHz. D. All of these. D
329. If a ship, in accordance with the requirements of regulation 10.1.1 (of the amendments to the 1974 SOLAS convention), is fitted with an INMARSAT MES, while at sea, shall:
A. Maintain a watch on 8414.5 KHz.
B. Maintain a continuous watch on at least one of the following HF DSC frequencies: 4207.5 KHz, 6312, 12577 or 16804.5 KHz.
C. Maintain a continuous watch on 2174.5 KHz.
D. Maintain a continuous watch of satellite shore to ship distress alerts. D
330. Which modulation type should normally be used for a radiotelephone connection? A. H3E B. J3E C. R3E D. F1B B
331. The radiotelephone silence periods are required:
A. Twice each hour for 3 minutes duration beginning on the hour and half hour. B. Once each hour, on the hour for 3 minutes duration.
C. Four times each hour for 3 minutes duration commencing on the hour, 14 minutes, 30 minutes and 45 minutes.
D. To be set by the captain of the vessel at the beginning of voyage. A
332. The radiotelephone silence period is:
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A. A time period when the radiotelephone watches receiver can be turned off because no traffic is sent. B. A time for testing to prevent interference with normal message traffic. C. Used to pass message traffic on a non-interference basis.
D. A 3 minutes period reserved for transmitting distress, urgency, or safety messages. D
333. The chosen of the 3rd DSC watch-keeping frequency on MF/HF combination radio stations should be appropriate to:
A. The ship’s position. B. Time of day. C. The propagation characteristics. D. All of these. D
334. Where a station in the mobile or mobile satellite service learns another mobile unit is in distress, why must she transmit a distress alert?
A. The mobile unit in distress in not in a position to transmit the distress alert itself.
B, The master or person responsible for the mobile not in distress or the person responsible for the land station considers further help is required.
C. It is ruled in Radio Regulations. D. All of these. D
335. Acknowledgement of receipt of a DSC alert would be performed by:
A. DSC equipment, on the frequency concerned. B. All of these likely.
C. SSB equipment, on the frequency concerned. D. VHF RT equipment, on the frequency concerned.
B
336. On which frequency should acknowledgements of receipt of DSC alert send:
A. The frequency, which was allocated for NAVTEX purposes. B. The frequency, on which the alert was received.
C. The frequency, which was determined by the master concerned. D. None of these. B
337. Which of the following is not a NBDP frequency?
A. 2174.5 KHz B. 4177.5 KHz C. 6312 KHz D. 8376.5 KHz C
338. Which one of the following keystrokes or characters is sent as part of ARQ communications to switch information transmission control from one station to the other?
A. The “ENTER” key. B. The go-ahead (“GA”) command. C. The plus and question mark keys (“Over”) D. The “END” key. C
339. Which one of the following keystrokes or characters follows most commands in an ARQ communications?
A. The plus (“+”) key. B. The “ENTER” key. C. The go-ahead (“GA”) command. D. The “END” key.
A
340. Which of the following keystrokes or characters is sent as part of ARQ communications to signal the end of the text of chargeable message?
A. Four “N”, i.e. “NNNN”. B. “BRK+” C. Four “K”s, i.e. “KKKK” D. Five periods (“…..”)
A
341. What should happen when an ARQ code is received by a NBDP station which is sending message
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