Pre Course Notes SRC/ VHF
Please complete this work before attending the one-day SRC / VHF course, this will make it so much easier on the day. You will need a passport photograph. No need to purchase any books. Just bring a pen and paper
Copyright 2015 David Peacock 01482 840780
There are 55 VHF channels; you must use your radio properly.
The right procedure + the correct channel = A good radio operator
Channels you must remember # (The rest you can find in a marine almanac).
Distress Safety & Calling 16# (Voice Comms)
Digital Selective Calling 70# ( No Voice on this channel)
Port Operations 12,14, (for the Humber Estuary)
Primary Inter ship 06#
Bridge to Bridge navigation 13#
Coastguard working 67#
All ships fitted with the Digital equipment have a 9 digit number allocated to them.
This number is called A Marine Mobile Service IdentityMMSI and is used to call a ship using a digital transmission.
Ships are also allocated a radio call sign ,think of this as being similar to a car number plate . This may be used for VHF voice communications.
Communication Range
Under normal propagation conditions VHF transmissions travel in a straight line.
The curvature of the earth’s surface restricts the communication range to a little more than line of sight. The higher the antenna the better.
Typical range between two small yachts antenna height 30ft 15/20 miles. The same yacht to a Coastguard station 20/40 miles.
Transmitted Power
The high power setting for a marine VHF radio is 25 watts. The low power setting is around 1 watt this reduces the detection range and the possibility of interference to other users.
Dual Watch
Allows the VHF radio to monitor CH16 and any other channel. When a signal is received on CH16 the radio locks on to that channel. Switch off the dual watch mode before you transmit
Operating Procedures
- Always listen and think before transmitting.
- Give the name or the call sign of the station called.
- Speak clearly and slowly
- The maximum length of a call is 1 minute
- You must then wait 3 minutes before calling again.
- The maximum length of a test transmission is 10 seconds
It is forbidden to:
- Broadcast to the world in general.
- Transmit without proper identification.
- Transmit false distress signals.
- Transmit bad language.
- All messages must be authorised by the ships master/Skipper/OIM.
- You must keep secrecy of correspondence.
- You must have a radio operators certificate or be directly supervised by a crew member that has
Remember the station called controls the communication
DISTRESS, URGENCY, AND SAFETY
Definition of DISTRESS:
When aVessel, Vehicle, Aircraft or Person is in grave and imminent danger.
And IMMEDIATE ASSISSTANCE is required
DISTRESS CALL AND MESSAGE CH16
MAYDAY MAYDAY MAYDAY
This is
SHIPS NAME X3
MAYDAY
Ships Name,call sign and MMSI spoken once
POSITION
WHATS WRONG
ASSISTANCE REQUIRED
PERSONS ONBOARD P.O.B.
ANY OTHER USEFUL INFORMATION.
OVER
WHO WILL ANSWER A DISTRESS CALL:
A Coastguard rescue centre
A coastal radio station
Any vessel in the vicinity
A MAYDAY CALL IMPOSES RADIO SILENCE ON CH16
MAYDAY RELAY
Is a message that re broadcasts a distress message?
DISTRESS WORKING
The following signals may be used
SEELONCE MAYDAY means keep off ch16
SEELONCE FINEE indicates the end of distress working.
EMERGENCY POSITION INDICATING RADIO BEACON EPIRB
These transmit on 121.5Mhz for homing. The EPIRB will also transmit on 406 Mhz .
EPIRB's transmit information to the satellites resulting in a very accurate position fix. They can be used if you are in grave and imminent danger.
URGENCY
Used when you are in trouble at sea but there is no grave and imminent danger. Can be used if you are dismasted, have an engine break down, lose your propeller or require medical assistance. /advice
The URGENCY Prefix is PAN PAN
Use ch16
PAN PAN X3
THIS IS
SHIPS NAME X 3
POSITION
WHATS WRONG
ASSISTANCE REQUIRED
OVER
The urgency signal does not impose radio silence but in practice stations usually keep
radio silence on ch16.
SAFETY
This is used for navigation warnings .Floating objects that are a danger to navigation. Gale warnings. Buoys and lights not in place. Ships out of command. Tugs towing pipelines etc. ships /small may transmit on CH16 . The Coastguard will use other channels.
SECURITE X 3
ALL STATIONS X 3
YOUR SHIPS NAME X 3
THE MESSAGE
OUT.
INTERSHIP COMMUNICATIONS
The initial call is on CH16. The vessel called controls the communications and will nominate the working Channel. I.e. 77,72,08,06. Only ships business no social chatting.
Call: ship x3, give your name x3, and wait for a reply.
PORT OPERATIONS
When approaching an estuary or port refer to your ALMANAC AND KEEP WATCH ONTHE CORRECT CHANNEL. You will receive all sorts of information. Weather and shipping movements. Usually on channels10, 12,14.
MARINA COMMUNICATIONS
Use CH80 for the UK; refer to your almanac when abroad. Call when you approach it will make locking and berthing easier.
YACHT CLUBS
Use CH37 (M1) for racing and berthing activities. No social chatting! No relaying messages ashore. Do not use your hand held VHF ashore, only aboard or in the ships tender.
COMMUNICATION WITH THE COASTGUARD
The coastguard is responsible for search and rescue.
CALL ON CH16. Usually CH67will be used to pass messages. Do not call directly on CH67. Since early 2004 coastguard stations only keep a loudspeaker watch on CH16.
All communications into and out of a coastguard station are recorded. Call the coastguard for any emergency their attitude is
“We’re here to help call us at any time”.
GMDSS
The Global maritime distress and safety system.
Uses a tone signalling system for DIGITAL SELECTIVE CALLING (DSC ) just like a mobile phone. Every ship over 300 tons and certain other vessels are fitted with DSC, each has its own Marine telephone 9 Digit number (fancy name MMSI, marine mobile service identity)
C
Humberside Radio Examination Centre David Peacock 01482840780
Distance learning Assessment
1.Under what circumstances should a Mayday call be transmitted? ……………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………
2.What is the meaning of the prefix SEELONCE MAYDAY?
……………………………………………………………………………………………………………………………
3. You are in collisionwith an unknown ship; on board with you are two adults and two children. You are about to abandon to the life raft.
Your present position is 5 miles south of Gibralta.
Write down the Distress call and message you would transmit. Your ships name is BULLDOG call sign MBCD6 MMSI No 235123456 which channel would you use for the voice message?
The above is story of a situation at sea. List the information in the right order ready for transmitting by voice
4.What is the meaning of the words SEELONCE FINEE? ………………………………...... …………………………………………………………………………………………….
You wish to contact the Coastguard. Which channel would be used? …………………………….
You are sending a passage plan to the Coastguard which channel is used?…………………….
What is theapproximate VHF range between two yachts mast height 30 ft?…………………………………….
Why would you use the low power setting on your VHF Transceiver? ………………………………………………………………………………………………………………………………………………………….
On which channel would you send an Urgency message?……………………………………………………..
What do the letters EPIRB mean? When would you use one? ………………………………………………………………………………………………………………………………………………………….
What are the following Channels used for? CH13………………………………………………………………
CH80………………… M1 …………………… CH06 …………………… CH70…………………………..
You sight a semi submerged 40 ton container .You are out of range of a
Coastguard centre. What type of message would you send? ……………………………………………………. Which channel would you use? …………………………………………..
13You make a call on CH16 there is no reply, how long must you wait before repeating
The call ………………………...... ………………………………………………………………………..
14. Give the phonetic words for the following: C………… G……………. X………… K………….
S…………….. D…………….. W……………… Q ……………… R……………
When would you use the URGENCY signal?……………………………......
- What is a Distress alert?...... #
- When would you send a Distress alert?...... #
All the answers will be found in the notes. Please complete this assignment; it will make the DSC/ SRC course so much easier on the day.
Do not forget your passport photograph!!!!!!!
The Phonetic Alphabet
A Alpha N November Humberside Radio Examination Centre
B bravo O Oscar 01482840780
C Charlie P papa
D delta Q Quebec
E echo R Romeo
F Foxtrot S sierra
G golf T Tango
H hotel U uniform
I India V victor
J Juliet W whiskey
K kilo X x-ray
L Lima Y Yankee
M mike Z Zulu
Learn the phonetic alphabet .
We will discuss your answers to the above questions during the SRC VHF Course
Digital Selective Calling (DSC)
It sounds difficult! You use it every time a mobile phone call is made. Enter the digits (Number) of the persons phone you wish to call this has now selected who you are going to talk to. So it is not difficult after all!
From January 2001 all marine VHF radios sold through a retailer (except handheld units) have had to feature digital selective calling (DSC), so what is DSC, why will it change the way we communicate and how is it used?
What is DSC?
DSC uses digital data, rather than voice to transfer information between radios.
Just like a mobile phone you can enter a series of digits into the radio, this will then select only the ship or shore station you wish to contact. Hence the term, Digital Selective Calling.
The effective range of communications when sending digital signals is also improved.
DSC is primarily intended to initiate ship-to-ship and ship-to-shore messages.#
DSC calls can also be made to alert individual ships or groups of ships that a voice message will follow. DSC distress alerts are used to initiate emergency communications with ships and rescue coordination centres. #
DSC eliminates the need for persons on a ship’s bridge, or onshore, to continuously monitor radio receivers on voice radio channels, including Ch16 .The Ch16 watch ended on 1 February 2005 and the coastguard no longer use a dedicated headset but rely on a loudspeaker watch.
What is a DSC controller?
A DSC controller is a unit that encodes and interprets DSC messages. In the majority of marine VHF radios this is built-in. DSC controllers have the facility to directly alert other vessels or rescue centres before opening voice communications in the normal manner, on the normal channels. In this respect, the system works rather like a pager with the recipient being alerted by an audio alarm, which has different sounds for routine and distress calls.
Before transmitting an urgent safety message you can digitally alert ‘all ships. Or before broadcasting a Mayday, in the time-honoured format, you can transmit a distress alert at the press of a red button, which will set off an alarm in ship and shore stations within VHF radio range.
What is an MMSI?
Maritime Mobile Service Identity (MMSI) numbers are a series of nine digits, which are used to uniquely identify a shore radio station, a group of ship radio stations and individual ship stations. When sending a DSC message the MMSI is automatically included, and you can address messages to specific shore stations, vessels or groups of vessels using their MMSI. The MMSI has a standard format (just like a telephone number) and it identifies the type of station, country of registration and vessel identity. MMSI numbers are assigned as a part of the ship’s radio licensing procedure. The ships Radio licence is administered by OFCOM and is free if you apply on line.
What is GMDSS?
The GMDSS (Global Maritime Distress and Safety System) is an integral part of SOLAS (safety of life at sea) and is a radio-based communications system designed to support the implementation of search and rescue (SAR) plans. The GMDSS provides for automatic distress alerting and locating in cases where a radio operator doesn’t have time to send a MAYDAY call, and, for the first time, requires ships to receive broadcasts of maritime safety information that could prevent a distress from happening in the first place.
The GMDSS consists of several systems, some of which are new, but many of which have been in operation for many years. The system will be able to reliably perform the following functions:
- Alerting (including position determination of the vessel in distress);
- Search and rescue co-ordination; locating (homing);
- Maritime safety information broadcasts (Navigational Text messages NAVTEX).
- General voice communications;
- Ship bridge-to-bridge communications (ship to ship safe navigation voice messages).
How DSC will affect you?
Since the 1st of February 2005 ships no longer need to monitor theCh16 VHF distress channel although in practice many vessels do. On the same date, UK Coastguard rescue centres ceased to use a dedicated headset monitor but now keep a loudspeaker watch on Ch16.
The Case for DSC
There is no question that GMDSS has a big part to play in improving safety at sea.
1.A vessel’s position and the time are automatically included in a distress alert if a DSC radio is connected to a GPS navigator (if it isn’t, the position can be manually input).
2.A digital alert is more certain of reaching a maritime rescue centre than voice transmission, having a slightly greater range and not being prone to misunderstanding.
3.The increasing use of the digital broadcasting channel, Ch70, should free upCh16for use during an emergency. CH16 can still be used as before for voice communications i.e. Calling, Distress, Urgency and Safety communications.
If you are a leisure craft you can still use your old VHF radio .
If you have a DSC radio then there are two ways of making a distress call
1.The digital distress alert, which includes your ships position.
2.The digital distress alert followed by the time tested voice mayday procedure.
End of Pre course work
Please email the question answers to
or before you attend the course .
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