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Marine Radio Operation

An essential skill for all sea divers. If you haven't yet got your VHF operators licence do so now, you never know when you are going to need it. Oh! and learn the phonetic Alphabet ASAP.


VHF Marine Radios

VHF marine radios are a great asset to all who use them. They are not chat lines however, and should be used for working messages only. Misuse of the equipment could disrupt other users within the area. All VHF radio users are legally required to hold an operators licence and he vessel to which the radio is fitted must have a ship radio licence. A 'station' is a term for a VHF Radio. As a general rule listen to the channel for 30 seconds before transmitting to ensure it is not already in use.

The Radio

All marine radio equipment must be approved according to government specifications. There is a maximum power output of 25W although 1W is usually sufficient for most activities other than distress calls or public correspondence.

Channels

Channel 6 and 16 are mandatory on a VHF radio.

Channel Purpose
16 International Distress, safety and calling
6 Primary Inter ship
8, 72, 77 Inter ship
12, 14 Port Operations
67  Small Craft safety
M, M2 Marina Special Licence
2, 24, 26, 28 Ship to shore (public correspondence)
6, 67, 73 Search And Rescue Co-ordination 

VHF Signals

The range of VHF is line of sight and has an Inter-ship range of 15-25 miles. Ship to shore range is about 30-50 miles. The dual watch (D/W) facility allows you to monitor two channels via switching. Do not transmit on dual watch. Digital selective calling uses CRS but requires an additional kit for the radio set.

The capture effect is when a receiver within range of two stations will receive only the more powerful or closer signal, the other signal will be lost.

Aerials

Aerial should be high and upright and clear of other aerials by at least 1M. An emergency aerial should also be carried.

Control of Communication

Ship to shore - coast radio station
Inter-ship - station calling
Search and Rescue - Vessel in distress, relay station, Coastguard, on scene vessel / aircraft

Duration of Calls

Test Call / Radio Check  - 10 sec
Calling on Channel 16  - 1 min
Calling again on Channel 16  - 3 min
Listen on channel before calling  - 30 sec


Distress calls

Coastguard use GMT all year round. Each station has an obligation to respond to a distress call: write down time, name, position, nature of distress, no of people on board and additional information.

If the Coastguard says 'wait' this means they will respond within 10 min's. Any longer than that should be given a reason prior. Only repeat things three times if it is a distress call. Other wise use their name once and your name twice. Distress calls should make the following 7 points in order:

  1. Distress call
  2. Identity
  3. Position (Note that the position is given in geographical area as distance 'from object' not 'to object' when working out bearing. Otherwise use Lat. and Long.)
  4. Nature of distress
  5. Information for search and rescue
  6. Invitation to reply
Message Meaning

Mayday (Distress)

Definition: When a vessel or person is in grave and imminent danger and requires immediate assistance. fire, accident damage, lee shore situation (under lee shore is when you are sheltered by the shore), diver not surfaced, man lost overboard, person is gravely ill. Example:

MAYDAY, MAYDAY, MAYDAY. 
This is Evelyn Rose, Evelyn Rose, Evelyn Rose

MAYDAY Evelyn Rose. 

My position is: 180 degrees, one mile from buoy number 1.

I am sinking and require immediate assistance

Four crew members on board, all safety equipment and 
EPIRB at 406 MHz

Mayday Relay

Mayday relays are transmitted when the station in distress cannot itself transmit a distress signal or when, although not in a position to assist a distress message is heard that has not been acknowledged. Example: 

MAYDAY RELAY, MAYDAY RELAY, MAYDAY RELAY. 
This is Yacht Fulmar, Yacht Fulmar, Yacht Fulmar

MAYDAY Evelyn Rose. 

Position is: 180 degrees, one mile from buoy number 1.

Yacht sinking and requires immediate assistance

Four crew members on board, all safety equipment and 
EPIRB at 406 MHz

Pan Pan

(note Pan Pan Medico no longer exists. Just use PAN PAN)

Definition : When a station has a very urgent message to transmit concerning safety of a ship, aircraft or person. Example:

PAN PAN, PAN PAN, PAN PAN

Hello all stations, Hello all stations, Hello all stations
This is Evelyn Rose, Evelyn Rose, Evelyn Rose

My position is: 180 degrees, one mile from buoy number 1.

I have been in a collision and require assistance of a tug

Seelonce Mayday

Radio Silence Definition. Imposing radio silence by controlling station

Seelonce Distress

Radio Silence Definition. Issued by other station

Example:

MAYDAY - SEELONCE MAYDAY, SEELONCE MAYDAY, SEELONCE MAYDAY. This is Severn Radio - Severn Radio - Out

Prudonce 

 

Seelonce Feenee

 

Securite

Security, Security, Security

Hello all stations, Hello all stations, Hello all stations
This is Evelyn Rose, Evelyn Rose, Evelyn Rose

My position is: 180 degrees, one mile from buoy number 1.

My engine has broken down and I am anchoring in a southbound traffic lane, Request ships keep clear, over.

 

NAME OF SHIP.......................      CALL SIGN................................... 


DISTRESS TRANSMITTING PROCEDURES
(For use only when Immediate Assistance required)

1.Ensure transmitter is switched to 156.8MHz.

2. If possible transmit two tone Alarm Signal for 1/2 to 1 minute.

3. Then say:

MAYDAY, MAYDAY, MAYDAY
THIS IS..................... (Ship's name or call sign 3 times).......... MAYDAY

followed by ship's name or call sign

POSITION............................................... 

Nature of distress....................................

Aid required............................... OVER

4. Listen for a reply and if none repeat above procedure, particularly during the 3-
minute silence period commencing at each hour and half-hour.

Example - If possible Alarm Signal followed by:
MAYDAY, MAYDAY, MAYDAY.
This is EVELYN ROSE, EVELYN ROSE, EVELYN ROSE
MAYDAY, EVELYN ROSE

Position:  54 24 north 018 33 West.
I am on fire and require immediate assistance. OVER.

 


Common Terminology
 

Radio Command Meaning

All after

Used after the proword 'SAY AGAIN' to request a repetition of a portion of a message.

All before 

Used after the proword 'SAY AGAIN to request a repetition of a portion of a message.

Correct

Reply to repetition of a message that has been proceded by the proword's READ BACK FOR CHECK  when it has been correctly repeated.

Correction

spoken during the transmission of a message means - An error has been made in this transmission. Cancel the last word or group. The correct word or group follows.

In Figures

The following numeral or-group of numerals are to be written as figures.

In Letters

 
The following numeral or group of numerals are to be written in letters as spoken.

I Read Back

If the receiving station is doubtful about the accuracy of the whole or any part of a message it may repeat it back to the sending station, preceding the repetition with the proword's I READ BACK

I Sat Again

I am repeating transmission or potion indicated.

I Spell

I shall spell the next word or group of letters phonetically.

Out 

This is the end of working to you. The end of work between two stations is indicated by each station adding the word OUT at the end of the last reply.

Over

The invitation to reply.  Note that the' phrase OVER AND OUT is never used.

Radio Check

Please tell me the strength and the clarity of my transmission.

Received

Used to acknowledge receipt of a message, i.e, YOUR NUMBER...RECEIVED. In cases of language difficulties, the word 'ROMEO' is used.

Say Again  

Repeat your message or portion referred to i.e., SAY AGAIN ALL AFTER... SAY AGAIN ADDRESS etc. (Note:- This is typical of the need to memorise all these catch phrases'. To use the word REPEAT  would be wrong REPEAT is used to emphasize. something).

Station Calling

Used when a station receives a call which is intended for it, but is uncertain of the identification of the calling station.

This Is

This transmission is from the station whose call sign immediately follows. In cases of language difficulties the abbreviation DE spoken as DELTA ECHO is used

Wait 

If a called station is unable to accept traffic immediately it will reply to you with the proword WAIT....

Minutes

If the probable duration of the waiting time exceeds 10 minutes the reason for the delay should be given.

Word After or Word Before

Used after the proword SAY.

Again

to request repetition of a portion of a radiogram or message.

Wrong

Reply to a repetition of a radio telegram that has been preceded by the proword's 'I READ BACK, when it has been incorrectly repeated.         

The phonetic alphabet
 

Letter Channel Pronounced as
A Alfa AL FAH
B Bravo BRAH VO
C Charlie CHAR LEE
D Delta DELL TAH
E Echo ECK OH
F Foxtrot FOKS TROT
G Golf GOLF
H Hotel HOH TELL
I India IN DEE AH
J Juliet JEW LEE ETT
K Kilo KEY LOH
L Lima LEE MAH
M Mike MIKE
N November NO VEM BER
O Oscar 0SS CAH
P Papa PAH PAH
Q Quebec KEH BECK
R Romeo ROW ME OH
S Sierra SEE AIR RAH
T Tango TANG GO
U Uniform YOU NEE FORM
V Victor VIK TAH
W Whiskey WISS KEY
X X-ray ECKS RAY
Y Yankee  YANG KEY
Z Zulu ZOO LOO

Other Points
 

Do Do not
  • Practice your procedure drills
  • Practice the phonetic alphabet
  • Transmit messages not authorised by the master (skipper)
  • Operate a radio without a licence
  • Transmit false or deceptive messages
  • Transmit without and ID name or call sign
    Close down station
  • Broadcast a message without expecting a reply
  • Broadcast unnecessarily
  • Communicate without using coast radio station

 

 

 

 

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Page last updated on October 16, 2007
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