I am looking for a solution to connect a digirig to a marine transceiver on an autonomous uncrewed vessel. The ability to monitor and transmit on channel 16 then switch to a working channel is the primary need. I believe FAA regulations will not allow non-marine VHF radios to transmit and it looks like all the listed Digirig compatible radios are not marine VHF type accepted radios.
The IC-M400BB looks to be an ideal radio due to it’s blackbox form factor but any marine radio would work if it can be fully interfaced with the DigiRig.
The alternative is the mimer softradio but am hoping the DigiRig will be cheaper.
Digirig will get audio to and from the radio, switch between receive and transmit (control PTT) and allow CAT control if needed and radio supports it. You mentioned switching between different channels which sounds like a case for CAT control.
Does the radio support CAT control?
Do you have the software in mind that will accommodate your use case?
This is a very interesting application. Please keep us posted on your progress with it.
I cannot find a marine VHF that advertises CAT control and believe that FCC regulates the usage of CAT controls for type accepted radios such as marine VHF. Mimer interfaces with most of the marine I-Com and other radios so there is a way, just not sure how they do it.
The homebrew CAT implementation can be bolted onto the radio if needed. Assuming that the switching of the channels is the matter of pressing buttons or clicking the rotary dials then the radio can be hacked with relay(s) so your controlling device can control them electrically when needed while maintaining isolation. You’ll need an Arduino board listening on the Digirig’s serial port for CAT commands and energizing the relays accordingly. Simpler integration options may be available depending on radio’s implementation.
Before diving into the workarounds, I’d confirm that you have a regulatory obstacle to using the stock ham equipment.
Interesting project. Have you looked at the NMEA standards which allow control over
many marine devices. NMEA 2000 allows for some control of radios including DSC calling. Interface might allow control you need?
You are correct that FAA regulations prohibit the use of non-marine VHF radios for transmitting on marine channels. When choosing marine equipment, the IC-M400BB is a solid choice due to its black box design, but integrating it with the DigiRig may be challenging since most DigiRig-compatible radios are not marine-band certified. One potential workaround is to use an interface that supports remote control of the IC-M400BB via NMEA or CI-V protocols, though Icom’s marine radios typically don’t have the same level of external control as their amateur counterparts. If full DigiRig integration isn’t feasible, an alternative approach could be using a dedicated RoIP solution like the Mimer SoftRadio, though it comes at a higher cost. Another option is to explore whether a Signalink USB or similar interface could bridge the connection, but that would depend on the specific data and audio interfacing capabilities of the IC-M400BB. If budget is a key concern, you might also look into whether a custom-built interface using an Arduino or Raspberry Pi could provide a cost-effective way to manage channel switching and remote operation.
This statement is misleading. Do you have diagrams of pinouts for the icom-ic-m400bb and other Marine Mobile radios? That would be helpful to configure cables for use with the Digirig.
