Flags, semaphores, and other systems

Flags, semaphores, and other systems
Frequency of the radio wave used for the maritime communication
International code flags
Morse code
VHF
SSB
Satellite communication
Geosynchronous satellites
Inmarsat System
The concept of maritime communication
Transmission of letters and numbers.
The figure code
Grammar notice - 'if sentences and the ‘unreal’ past
Layout COMMUNICATION AT SEA

VOCABULARY
Intermediary
Pennant
Alignment
Dot
Headquarters
Dash
Appliance
Relay
Input

VOCABULARY
Pennant (n) - a flag occasionally flown
Dot (n) - a short sound or click
Dash (n) - the mark (– ); a long sound or signal
Relay (v) - receive and pass on (a message, etc.)
Intermediary (n) - a go-between, mediator
Alignment (n) - arrangement in a straight line
Headquarters(n) - the main office
Appliance (n) - a device for performing a specific task
Input (n) - the act of putting in

The communication effective
The communication uncompleted

The communication uncompleted - no feedback confirming reception of message by recipient.
The communication effective – communicator received the confirmation on acceptance of message by recipient.

"All wheel orders given should be repeated by the helmsman and the officer of the watch should ensure that they are carried out correctly and immediately'".
SMCP, 2001

Structure of the communication
On Board
Communication
External
Communication

Communication at Sea
Written messages
Flags, semaphores, and other systems
a message could be sent to anyone who could see it and understand it.
One of the oldest methods of remote communication

International Code Flags

International Code Flags

International Code Flags

International Code Flags

International Code Flags

International Code Flags

International Code Flags

International Code Flags

International Code Flags

International Code Flags

International Code Flags

International Code Flags

International Code Flags

VHF

There are two basic kinds of radios aboard ocean-going vessels.
Marine VHF (very high frequency) radios require an uninterrupted line of sight between antennas.
This limits their range.

Marine SSB (single side-band) radio - to communicate over very large distances.
SSB has a greater range than VHF.
It does not require a line of sight between stations.
Transmitting on SSB requires a great deal of electricity .
SSB

Satellite communication

Satellite communication
Satellite communication - a new alternative for long-distance communication
Many advantages over conventional point-to-point radio:
A digital signal is transmitted upward to a satellite.
The satellite relays the signal to another satellite.
Satellite communication is private.
It allows direct access to the global communication infrastructure.
It is not affected by atmospheric or meteorological conditions.

Geosynchronous satellites
Most satellites - in geosynchronous, or geostationary, orbits.
Each satellite - at an altitude (22.300 miles or so)
Its speed around the earth matches the earth’s rotation.
Both the satellite and the surface of the Earth are rotating around the Earth’s axis
They are rotating at the same rate
Satellite appears to stay in one place over the Equator.
This simplifies signal transmission.

Inmarsat system
Inmarsat, or International Maritime Satellite - an international partnership of government and private entities representing 75 countries.
Provide mobile satellite communication services to the world.
Uses four of its own satellites
Leases maritime communication capacity on several other satellites.
All of the units are in geosynchronous orbits.

Concept Diagram of Maritime Communications

Transmission of Letters and Numbers.

The Figure Code

Questionnaire
1. What is the oldest method of remote communication?
2. How many International Code Flags are there?
3. What is any Morse Code message composed of?
4. What is the meaning of the message composed of three dots + three dashes + three dots?
5. What is the meaning of the abbreviation VHF? What are the disadvantages of VHF communication?
6. What are the two basic kinds of radios aboard ocean-going vessels?
7. What allows direct access to the global communication infrastructure?
8. Is satellite communication affected by atmospheric or meteorological conditions? Why?
9. What simplifies signal transmission to the geostationary satellites?
10. Do you happen to know the altitude of geostationary satellites? How high are they?

Questionnaire
11. What messages is Channel 16 reserved for?
12. Why should Channel 16 be permanently monitored?
13. May Channel 16 be used for routine messages?
14. When must the phonetic alphabet be used by a seafarer?
15. Do you happen to know the Figure Code? Can you state your year of birth using it?
16. Why are communications at sea so essential nowadays?
17. Between what responders can the communications be effected?
18. Can you name the simplest method of communication? Please, do it!
19. What is the primary condition for successful semafore communication?
20. What does each pennant represent in Flag Communication?