UNIT 7 COMMUNICATION

1. UNIT 7COMMUNICATION COMMUNICATION TYPES

2. Marine communication can be classified as audio and visual or as follows • Audio Communication • Visual Communication • Radio Communication • Satellite Communication

3. AUDIO COMMUNICATION Audio communications can be made using ship’s whistle, ship’s bell , gong or siren.

4. Ship’s bell

5. SHIP’S WHISTLE

6. VISUAL COMMUNICATION • Ships carry lights to be noticed by other mariners at night. • Knowing the lights, a seaman can tell whether the other ship is moving away or approaching.

7. The light from a lighthouse also provides information. Each lighthouse has its own code of long and short bursts which tell the mariner which lighthouse it is.

8. The flags that a ship flies also provide means of communication.

10. Semaphore is a visual signalling code in which flags stand for different letters or numbers. • Before the invention of the telegraph, semaphore had been used to transmit messages between distant points.

11. SEMAPHORE B ERROR

12. An Aldis lamp is used for flashing messages in Morse code.

15. RADIO COMMUNICATION • Modern ships carry radio communication equipment and usually use VHF radio for communication.

16. Other communications such as facsimile and computer data can also be transmitted by using a modem.

17. VHF radio has a short range so that long distance communication is possible using HF radio.

18. SATELLITTE COMMUNICATION Satellites can provide continuous communication coverage over most of the earth.

19. Satellites are classified by the height at which they orbit.

20. Satellites orbiting about 1000km above the earth are LEO (Low Earth Orbit) satellites. Satellites flying between 1000km and 35,860km above the earth are MEO (Medium Earth Orbit) satellites.

21. In a circle 35860 km above the equator, there is an area where the satellites orbit the earth at the same speed as the earth rotates.

22. Satellites launched in this ring are called GEO (Geosynchronous Earth Orbit) satellites.

23. A specific satellite system established by member countries of the IMO is a GEO system called INMARSAT. This system offers voice, facsimile, data and distress communication systems.

24. ANSWER THE QUESTIONS 1- What are the means aboard for audio navigation?

25. 2- What do ships carry for visual communication?

26. 3- Do ship lights help navigators?

27. 5- What is an Aldis lamp used for?

28. 6- What is the most common radio communication way?

29. 7- What is the advantage of using HF instead of VHF?

30. ETYMOLOGY Audio < Latin, audre, hear

31. Communicate< Latin, communicare,to make common <communis, common

32. Semaphore< Greek, sēma, sign+ -phoros, bearer

33. Message<Latin, missaticum < mittere, to send Visual < Latin, visus, sight < videre, to see

34. SOME WORDS Facsimile (n) - Electronic transmission of written material

35. Orbit (v) -To move round (the sun, the moon or any planet) in an orbit

36. Ask questions to the underlined words. 1-The flags provide means of communication.

37. What provides means of communication?

38. 2-The member countries of IMO established a satellite system.

39. Whatdid the member countries of IMO establish?

40. 3- INMARSAT system offers voice, facsimile, data and distress communication

41. What does Inmarsat system offer?

42. 4-Facsimile and computer data can also be transmitted by using a modem.

43. What can also be transmitted by using a modem?

44. 5- An Aldis lamp is used for flashing messages in Morse code.

45. What is an Aldis lamp used for?

46. 1-Which one is not a visual communication way? a. flags b. Aldis lamp c. engine telegraph d. semaphore e. ship’s whistle

47. 1-Which one is not a visual communication way? e. ship’s whistle

48. 2-What uses Morse code? a. ship’s light b. Aldis lamp c. lighthouses d. buoys e. semaphore

49. 2-What uses Morse code? b. Aldis lamp

50. 3-Which is not a communication method? a. INMARSAT b. VHF c. Morse code d. telegraph e. GPS