Multiple VHF's single MMSI Question

[Chuck - Raymarine - Moderator]

Welcome to the Raymarine Forum Jon,

General comment: The system is not designed to function in the manner which you have described. Should all VHF radios share the same MMSI and be configured to automatically respond to position polling requests, then all will respond. Typically the initiating VHF radio must acknowledge each received DSC position report received. Should multiple VHF radios automatically respond to the position polling request, then the possibility exists that the initiating VHF radio may not be able simultaneously process each of them. In the worst case scenario, it may only be able process a single DSC response. This subject should be researched via the VHF manufacturer. However, should it simply be desired that any one of the auxiliary craft be able to issue a distress message, have the ship's VHF radio respond to the distress message, and have the ship's VHF radio transmit the DSC position report to the MFD, then this should indeed be possible. Any DSC position reports transmitted to the MFD will cause the MFD to generate a corresponding alert and then provide an option to plot the position of the sender as a waypoint (not to be confused with an AIS or MARPA target). Should it be desired to perform DSC position polling, then the DSC VHF radios operating on the auxiliary craft each be programmed with unique MMSIs. Alternatively, should it be desired to continuously monitor the position of multiple support craft, tenders, recreational craft, etc., then it would be necessary to equip each auxiliary craft with an AIS Class B transceiver, each of which will in turn have a unique MMSI. Finally, the software presently available for Raymarine MFDs does not currently feature ability to initiate a VHF call.