27 Mhz marine radios

 27 Mhz marine radios are short-range entry-level units. 

They are the cheapest ship stations, run on a 12v battery and don't require an operators licence (certificate). They are good for inshore boating, on sheltered waters like tidal estuaries-rivers or protected bays. The maximum range is about 5 nautical miles (10km) line of sight only. Rescue bases sometimes monitor them, but it's best to check with your local base if they do this safety service or not

Radio traffic is generally more localised, among recreational fishermen, trailer sailers and other small craft, perhaps with a marine rescue base on listening watch by day.  

New units are around A$200 (plus aerial), seen some secondhand ones for about A$40.

They have 2 calling channels and 8 working chanels to talk on. A Channel sticker can be placed beside the radio station which indicates which chanels are best for different groups. 

Calling Channels 88 and 86 are for initial calls or distress calls. Listening watch is on these.

The working channels. Ch 96 and 94 are for talking to other recreational boats. Ch 94, 90, 91 for talking with Coast Guard or VMR bases. Safety/weather messages are  on ch 98. The other 3 channels are for talking with commercial vessels (if they have a 27Mhz).

There are no repeater channels, so range can't be extended as for VHF radios. 

But they might be ideal for some inshore boaties who would like to stay easy and simple. General operating procedures and calls are otherwise similar to other types of marine radio like VHF.

Most State Authorities encourage study of the VHF radio handbook for calling procedures information. 27Mhz chanels are simplex (single frequency) the handset has a "Push to talk" (PTT) button on it which must be released after "over", so the other radio can respond.

The main thing is to initiate calls on a calling channel, say Ch88. Call another boats/VMR/CG bases name 3x, then "this is", your call sign 3x, your contact message and "over". Await reply, always say "over" to allow the other radio to transmit next. Then go to an agreed working channel to continue conversations. End communications with "OUT". Then go on "listening watch" on Ch 88. Keep the radio switched on while active on the water. 

The VHF 12v battery procedures/servicing apply. 27Mhz have their own aerial type as well which must also be well fitted/high as practical.

It does seem like VHF's (and mobile phones/apps) are taking over from the old 27 Mhz technology. If buying a new radio my choice would be VHF over 27Mhz. (but it's needed for semi-offshore cruising) It's also what most marine rescues recommend or encourage. Still the humble 27 mhz might still have appeal and do a good job for some who don't wish or plan on going out too far.

This is a good web page about getting into all 3 types marine radio's (27mhz, VHF and HF) what each type can or can't do and the licencing requirements.

marine radio safety -South Australian Government

Long Range radio - HF radio

A LROCP (Long Range Radio operators Certificate of Proficiency) is required to operate an HF long range radio in Australia.    It's an advanced level radio certification, usually for profesional seafarers, blue water or offshore yachtmen or volunteer marine rescue crew members. The licence was formerly known as a MROCP (Marine radio Operators Certificate of Proficiency).

Courses are usually available with with marine training providers or at local marine rescue bases.  The LROCP in my area costs around A$190 or so in 2023 ($60 for manual)  The course also covers and expands on the SROCP content  (short range radios, VHF etc)

HF radios

These are long range transceivers. For serious blue water voyaging or offshore use beyond VHF ranges.

They bounce radio waves off the ionosphere, so the signals can go far beyond the horizon and around the earth. A knowlege of the channels frequency capabilities is required under different atmospheric condiditions. Different frequency channels are used to optimise the signal clarity/ range to operate in etc.

Marine HF radio monitoring by shore stations in Australia has recently switched from States/Terittory jurisdiction to  AMSA a federal body. AMSA HF Radiotelephone monitoring (Dec 2021). This  interesting story in the lead-up to the changes Australia floats plan to phase out HF radio monitoring by 2022  (Oct 2019).  It seems that HF radiotelephony is rarely used for distress calls far at sea nowdays, due to the advancement of GPS EPIRB's and similar technology taking over this role (including HF DSC units)  But AMSA still monitors HF for distress calls and many other services such as BOM weather information and warnings etc are still broadcast to mariners who are well beyond VHF range.

HF marine radios arent cheap, they cost several thousand dollars (eg $2,500 - >$6,000 depending on capability functions and brand)