Types of Radio
The ability for shipping to communicate, both with the shore and each other, in order to pass navigational, safety and emergency information is vital. In an emergency, effective radio communication may be the only realistic way that a vessel can alert the Search and Rescue authorities and obtain help.
Broadly speaking, there are three types of radios used for voice communications at sea, (known as radiotelephones)
VHF (Very High Frequency) radios are the commonest type of radio used for two-way voice communications. Although they have a limited range, they are simple to operate, have a large number of channels and can be conveniently miniaturised. Consequently VHF radios are used wherever there is a need for fast and simple voice communications, from aircraft to taxis, from building sites to shipping.
HF and MF Radio's
Compared to VHF radios, MF, (Medium Frequency) and HF, (High Frequency), radios are slightly more complex to use. They have a greater range, (150 - 300 miles for MF and global coverage for HF. MF will only reach 150 miles from an ALB). They require much larger antennae and far more power to operate, which restricts miniaturisation.
There is an increased use in voice communications via satellites and this may develop into a common communication system. Currently, however, it is an expensive option and within the maritime environment tends to be limited to large shipping.
The VHF Operators Licence
The old radio operator’s Licence for a VHF radio was known as the, ‘Restricted Certificate of Competence in Radiotelephony, (VHF only)’. This has been replaced by the ‘Short Range Certificate’ and candidates will now need to demonstrate additional knowledge of the ‘Global Maritime Distress and Safety System’, or GMDSS. The SARROC course encompasses the SRC syllabus and attracts the same Authority to Operate