Ian Waugh - A Mariner\'s Guide to Marine Communications

(on H764/HUOkHz - ChHI6)
jllstina this is US Coast Guard Boston, Boston - Over
Boston this isjllstina - Over
jllstina this is US Coast Guard Boston - standby for connection to CIRM
jllstina this is US Coast Guard Boston - you're connected - go ahead
And the radio log onboardJustinalGJUS would look like:

Date/time Station
UTC To
27. 10. 01
0830 US CG Boston
0831
0832 /40

Station

From

GJUS

GJUS

Remarks

DSC Urgency Alert sent J Uhuru

Rq Urgent Med' Advice (R -go Ch816)

(connected with CIRM)

Frequency

Channel or

Satellite

8414kHz

8291kHz

Ch816

(then continue to log all relevant information until the situation is resolved)

Author's explanation:

Justina chose 8MHz because of distance from Boston, and time of day/night. A different HF

frequency may have been appropriate for a different distance/time. The US Coast Guard

received the initial voice call on 8291 klIz simplex but, for a link call to the CIRM, moved

Justina to a duplex channel (where the two parties could have a normal telephone

conversation, rather than use the simplex 'only one person speak at a time -Over'type of call).

Question: When a ship is working through a Coast Station for an
Urgency call, who controls communications?
Answer: The Coast Station. 'Control' means that the Coast Station
will decide the working channel to be used (if different from that
offered/ chosen by the vessel) and make the first call on that working
channel.

Example Using Inmarsat-A/lnmarsat-B telephone

communications to make an 'Urgency' call to a Medical Centre

• for Medical Advice

Inmarsat-A Calling Procedure

(generic process)

Lift the handset

Receive Dial Tone (from own equipment)

Select Routine Priority/ Telephone (01)

Select LES

Press ''*'' key (to initiate the call)

Receive Dial Tone from LES

Key 32,*, (Await connection to Medical Centre)

Inmarsat-B Calling Procedure

(generic process)

Lift the handset

Receive Dial Tone

Accept Default LES or

Select another LES

Key :~2,*,

(Await connection to Medical Centre)

The LES is programmed to connect code 32 calls direct to a

Medical Centre (either a doctor/hospital in the country where the

LES is situated or, in the case of US and some other LESs - to the

MARINE COMMUNICATIONS 119