VHF – SRC – DSC - MMSI – MF

In the last few years there have been many changes in radio communication at sea, in fact these changes are so recent that many of us don’t even know exactly what this new technology actually does. This in my view is not helped by the fact that the descriptions of all these new systems have been reduced to a series of letters – a custom which I feel has come from the far side of the Atlantic where they have a fondness for abbreviation. An early example being the ‘CQR’ anchor, which stands for ‘secure’!

The meanings of these abbreviations are as follows:

VHF – Very high frequency radio-telephone describes the type of two way radio that has been in general use on ships, yachts and motor cruisers for about the last thirty years. Prior to that most private yachts and motor cruisers had no form of two-way radio on board. VHF gives a range of about 15 miles from boat to boat or up to about 30 miles from boat to shore station. This range is dependant on the height of the arial on the boat & on the shore station.

An operators licence is necessary in order to be able to use a VHF radio, this involves a one day course. We are very fortunate now in having 2 RYA Sailing Schools in the Algarve who offer VHF/DSC radio operator courses, they are as follows: 

The schools are:

1. Faro Sailing School at Ayemonte (just over the border in Spain) Email: This e-mail address is being protected from spambots. You need JavaScript enabled to view it Tel:  0034 959 321824.
      
2. RU Sailing at Lagos Marina. Email:  This e-mail address is being protected from spambots. You need JavaScript enabled to view it   Tel: 00351 918828085              

In addition to an operators licence your vessel is also required to have a ‘Ship Radio Licence’, for an application form go to www.radiolicenceforms.co.uk/ShipApplication.asp.

SRC – Short Range (Radio) Certificate. This is the certificate that has replaced the VHF certificate and incorporates an understanding of the new DSC (Digital Selective Calling) system which is covered below.

DSC (Digital Selective Calling) All non-portable VHF sets purchased since 2001 will either have a DSC controller incorporated into the set or have a DSC controller as a separate unit.

The controller transmits a signal on channel 70 that lasts about 0.5 seconds to initiate a distress alert or to indicate to a selected station or stations that you are calling them. It is similar to a pager, but has the added feature that with a distress call all stations that receive the call will change to channel 16 automatically. With calls of a non-distress type to a selected station or stations the receiving sets will automatically change to the ship-to-ship channel (Channels 6, 8, 72 or 77) that has been selected by the calling station.

VHF/DSC sets should be interfaced with a vessels GPS and so with a ‘Mayday’, call the vessels position will automatically be included in the transmission on channel 70, if the set is not interfaced with the vessels GPS the position will have to be entered manually which of course takes time and can lead to errors.

For other types of urgency calls, other than Mayday, that can be selected on the DSC controller, the vessels position is not sent out with the call and so it is very important to include your vessels position in your follow-up transmission on Channel 16.

MMSI (Maritime Mobile Service Identity) This is a 9-digit number which will have been programmed into a VHF/DSC radio and is always transmitted by the controller when a transmission is made on channel 70. All coastguard stations have their own MMSI numbers and so can be called using channel 70.

The VHF/DSC radio has a memory in it rather like a mobile telephone so that you can programme into it your friends MMSI numbers and the number of your local coastguard station and stations that you are likely to be close to on a summer cruise.

Prior to purchasing a new VHF/DSC radio it is essential to first apply for your boats radio licence (see above), your radio licence when it arrives will have on it your MMSI number which can then be programmed into your new set by the dealer. Some VHF/DSC radios will work without an MMSI number having been entered, some won’t. Some sets can be programmed with an MMSI number by the owner, but most have to be done by a dealer.

If you buy a boat that already has a VHF/DSC set on board it is essential that you contact the Radio Licence Centre and give them details of the boats change of ownership.

MF – Medium Frequency Radio is for communication over a much longer range using an SSB (Single Side Band) radio, this type of radio requires a different licence which can be obtained from the Radio Licencing Centre and a different operators licence which to qualify for you must do a four day course.

We do not have a school offering this course in English in the Algarve or for that matter anywhere in Portugal, but there is an excellent school in Bursledon near Southampton run by Bob and Claire Smith called YachtCom. They offer four day courses which cover the complete GMDSS syllabus. To go to the YachtCom web site click here. Yachtcom which is an RYA Training Centre also offer VHF/DSC (Short Range Certificate) and Radar courses.