The VHF Marine Radio band (156 - 174MHz) has been allocated internationally for the exclusive use of two-way radio equipment with fixed technical standards for marine use. Theoretically, you can buy a VHF marine transceiver in Country A and it will work in any other country. The reality, however, is slightly different. There are 56 channels allocated across the radio spectrum for Australia shown above, and the main emergency channel, channel 16, is the same all over the world! There is a secondary distress channel, channel 67 and it is also universal. When you operate a VHF Marine transceiver you monitor Ch. 16 (in case someone makes a distress call) and you can actually use that channel to calla colleague to contact them on the water. Once you have made contact, you immediately switch to another channel to keep Ch. 16 clear for possible emergency use. It is wise to confer with your colleague before going out to agree on the alternative channel, say Ch. 10. Then you don't have to broadcast what that channel is to discourage people from snooping in on your conversation. The non-emergency channel allocations may have local specific uses (such as harbour management, etc.) and this info appears in the manual that comes with the equipment when you buy it, if you buy it in Aus/NZ. RANGE: For most amateur boating operations you should get plenty of range with VHF marine. A good fixed installation (not handheld units) should give you 25km line-of-sight. Conditions vary enormously at sea, so don't depend on this. Most of the time someone will hear you and you can relay messages if necessary. Volunteer coastal stations monitor Ch. 16 generally 24 hours a day. PRIVACY: Remember your first conversations can be heard by anyone on Ch. 16. Depending on how sophisticated your VHF unit is, you can configure it to have a private conversation with a colleague who has similarly equipment set on a non-emergency channel. One of the best features of VHF Marine use is that you do not have of be aware of actual frequencies. You can then think just in terms of channel numbers. Setting up when you go out. If you like, you can go straight to your nominated channel and bypass Ch. 16 as much as possible. You can arrange 'skeds' (i.e. schedules) to monitor, say Ch. 10, at 15 minute intervals, quarter to the hour, on the hour, a quarter past and half past for 2 - 3minutes and then the rest of the time on Ch. 16. Happy boating!