Checking your DSC VHF radio

The rules are that we must not press this button and make a DSC distress alert call unless there is a real emergency. DSC ship radios normally have a programme to test that the radio is functioning without making a distress alert call. But how can we be sure that the Coast Guard will actually receive our distress call in an emergency?

The following advice has been supplied by e-mail from Solent Coastguard:

Guide to checking your yacht's DSC in the Solent Coastguard Area. (Beachy Head to Hants/Dorset border and out to median line).

1. Select Ch. 67 on VHF, listen and check channel is free for traffic (avoid interrupting traffic in progress). Have your MMSI number and international call sign to hand.
2. Make a voice call, "Solent Coastguard this is....(Name of Vessel) - request DSC check, over".
3. Wait for voice reply. (the operator may be on the 'phone or dealing with traffic on other aerials along the coast).
4. The Coastguard operator will reply by voice and may ask you for your MMSI number.
5. If approved, you should select 'Solent CG' from your set's directory or input Solent CG's MMSI Number, that is 002320011, and send a 'routine' message.
6. Remain listening on Ch. 67.
7. Solent CG will acknowledge your DSC request by DSC and your set will change to the working channel selected by Solent CG. (Normally Ch. 67).
8. Solent CG will then call you by voice on the working channel and indicate the DSC signal strength (1/5 to 5/5) and which aerial your signal was received on. 3/5 is normal 5/5 is excellent.

Notes:

Do not under any circumstances use the distress alert button for a test. Immediate Search and Rescue action will take place if a DSC Distress Alert is received. The Distress Alert goes to all stations, it will sound alarms on all stations and automatically takes priority above other DSC traffic.

Do not under any circumstances use the Urgency & Safety option for a test. Both options will trigger alarms on all stations.

From our experience, DSC data signals travel much further than VHF voice R/T. If the Distress option is activated in error you must:

1. Cancel the DSC transmission (once activated the set will continue to transmit the distress alert at regular intervals). On most yacht-DSC equipment the only way to do this is to switch the set off and then on again, but please read your manuals regarding this.
2. Once you have stopped the DSC alert signal you must then make an all-stations broadcast on VHF Ch. 16 giving your vessel's name and MMSI number and state that the DSC distress alert was sent in error.

We are trying to reduce the number of 'radio checks' made to this station. With radios being fitted to vessels from jet skis, RIBs etc, upward, the growth in 'radio checks' continues. We are suggesting that you should perform 'radio checks' with other vessels, marinas etc. and certainly not request 'radio checks' on Ch. 16.

Once having made a DSC check, future 'radio check' requests should confirm that your equipment is working without the need to frequently ask CG for further DSC checks.

Solent CG is the only one in the UK that continually monitors Ch. 67. This is to reduce the amount of routine traffic on Ch. 16. There is no need to 'DSC call' Solent CG for 'routine' traffic. Just call by voice on Ch. 67 as we are always listening on this channel. If you need to call any other UK Coastguard then you can use DSC and they will acknowledge and select a working channel for you.

It is important that you read and understand the instructions that came with your set. All have differences and some automatically select 'Telephone Call' options by default. if this is the case then you must deselect this option otherwise we cannot acknowledge your routine call. ('Sailor' sets often select the 'Telephone' options). The option to make direct telephone calls using DSC is no longer available in UK and most foreign waters.

Other tips:

Keep an Emergency Card next to your set showing your vessel's name, call sign, and MMSI number and instructions on how to send a Distress Alert.

During your safety brief, instruct all the crew on how to use the set in an emergency. The skipper may be a casualty.

Be prepared to spell the vessel's name. (For example on our databases we have a GT, Gee Tea, Piston Broke, Wight Dawn, White Dawn etc. all of which can have different spellings and at times of crisis we need to look for the right vessel).

Once a DSC Alert for Distress, Urgency or Safety has been transmitted (unless you have abandoned) you should follow up with the correct voice procedure (i.e. MAYDAY, PAN or SRCURITE). The reason being that the Alert only includes the vessel's identification, type of alert and position. The RCC receiving the alert will action the alert but would like to know more, e.g. the number of persons on board, the type of assistance required, etc. The voice transmission will also enable direction finding equipment to confirm the casualty's position.

Above all make sure that all users have attended an RYA VHF SRC Course and follow correct radio procedures.