Here is some information that I hope is useful for members crossing oceans or exploring island chains and coastlines.

There are very distinct advantages of using the DSC capability of ICOM 's M802(DSC) and M801(E/A) radios for boat-to-boat calling for General communications. But to get it working requires amendments to the default radio setup.

The default setup assumes that - apart from comms on 2 Meg MF frequencies - all communication from small-craft will be with coast stations. Therefore, the default DSC calling setup on the 4, 6, 8, 12 and 16 Meg DSC General calling channels is duplex, and cannot possibly work for boat-to-boat calling.

The reality is - according to my contacts in the GMDSS/IMO world - there are no government run coast stations anywhere in the world monitoring for DSC calls on these General calling frequencies. Government run HF/SSB coast stations only provide a listening service on the DSC Distress calling frequencies, which are simplex; so Distress calls can reach other nearby vessels, as well as distant coast stations.

But boat-to-boat DSC calling using the General receiver/transmitter in these radios creates significant day-to-day operational benefits for crews because these radios can be left on 24/7 in a speaker muted quiet mode, with the radio (not the crew) doing the work of listening for DSC calls - General (Individual or Group) and Distress (All call).

Three distinct advantages arise by maintaining HF/SSB radios in a 24/7 DSC watch:

1. Groups of yachts travelling together can provide quick response 24/7 mutual support for each other. Without needing to wait for the next voice sked.

2. Groups of yachts can immediate contact either another specific yacht (by sending a DSC Individual call to that yacht 's MMSI), or the entire group (by sending a DSC Group Call) to get advice about a dinner menu, anchorage, technical problem etc.

3. Yachts become immediately accessible S&R resources for any other mariners to contact via a DSC Distress call. This also applies to MRCCs making a DSC Distress call to find a nearby vessel to go to the site of an activated EPIRP or PLB.

To get these benefits from your M802(DSC) or M801(E/A) requires some straightforward changes that are detailed in the two attached documents.

Also attached is a document with a report from the skipper on a yacht participating in the ARC/WCC rally group crossing the Indian Ocean in 2015 regarding the process of getting the group to make effective use of their DSC capable HF/SSB radios to create a 24/7 mutual support network by first, making the necessary amendments, and second, utilising their Group Call ID to give all the crews the ability to send one DSC call to alert all the other radios in the group, simultaneously, to then make voice contact.

I hope this is useful. Any comments or questions, I 'll try to respond. Or email me at radio@bruneibay.net

Best wishes

Allan Riches
OCC Port Officer - Brunei