27MHZ radios are the less expensive of the two types of Marine radios. However there generally is less than $50 difference between the 27MHz and VHF radio.
The frequencies range from 27.6800MHz to 27.9800MHz. using AM mode Although the 27MHz radio is less expensive it only has a maximum power of 4W which is considerably less than the 25 watts of a VHF radio. The transmission is generally "line of Sight" and has a range up to 10 - 15 nautical miles compared to the VHF which should be effective over 20nM. 27MHz radios generally have a single select button (if needed for emergency) to allow a call on channel 88. Channel 88 is the emergency or calling channel for 27MHz radios and channel 91 is the working channel for the coast off Crowdy Bay and Harrington.
Using your 27MHz Radio If you need information or assistance while you’re out on the water, use the "Calling or the Distress" channel 88 to make the initial contact with our radio base. You will then be asked to go to a “Working” channel which for Crowdy Harrington's area is channel 91. The Radio Operator will advise to change to channel 91 as part of the initial contact. Calling on the Radio Be sure to listen for any other radio traffic before making your call, otherwise you might not be heard or you could interrupt another user’s transmission. Speak slowly and clearly.
Your initial call should be on channel 88 on the 27MHz radio. When making an initial call, give the call sign of Marine Rescue Crowdy Harrington three times and your own call sign three times. Your call sign will be the CB number given to you by our base or maybe the number given to you by another base if you have registered with another Marine Rescue Base eg CC55 for Central Coast boat number 55 or the name of your boat eg "LazyBoy" etc. This is to help ensure our radio station knows you are calling them and who you are.
Example: You: “Marine Rescue Crowdy Harrington, Marine Rescue Crowdy Harrington, Marine Rescue Crowdy Harrington. This is (name of your boat) LazyBoy, LazyBoy, LazyBoy. Over”
Our base station will respond and ask you to go to our "Working’’ channel - channel 91. Radio operator: “LazyBoy, LazyBoy, LazyBoy. This is Marine Rescue Crowdy Harrington, Marine Rescue Crowdy Harrington. Please go to nine one and call back. Over”
You: “Marine Rescue Crowdy Harrington, this is LazyBoy. Going to nine one. Over” Now change your radio channel to 91 and call the base a call again.
You: “Marine Rescue Crowdy Harrington, this is LazyBoy. Over"
When our radio operator replies seek the information you want or advise your plans. If you are logging on to go out to sea or up river advise the radio operator that you "wish to log on."
You: "Marine Rescue Crowdy Harrington, I wish to log on." The Radio Operator will ask you for a little more information if you haven't logged on before and in particular "Your boat registration" "How many persons on board" and "Your mobile phone number"
When your communications are complete, advise the shore station that you’re returning to the calling channel: You: “Thanks Marine Rescue Crowdy Harrington This is LazyBoy returning to channel 88. Out" The radio operator will respond: “This is Marine Rescue Crowdy Harrington. Out.” Now switch your marine radio back to channel 88 on your 27MHz radio and get back to enjoying your day out.