A flashing RED Status LED indicates a high VSWR reading or potentially a Power Amplifier fault.

For the flashing RED Status LED issue, with the 12v power turned off to the AIS Transponder, I would visually inspect the BNC antenna connector on the AIS and make sure there are no signs of connector damage. Then connect up whichever VHF antenna you have the most confidence in. Now power ON the AIS Transponder and immediately join its wireless network and bring up the web interface before the unit has got a GPS position fix and tried to transmit or use ProAIS2 if your AIS transponder don’t have a web interface.

Now watch the VSWR reading and see what value is displayed after the first couple of transmissions. If it is greater than 5:1, then it has a high VSWR and will soon start to flash the RED Status LED.

The most common cause is the VHF antenna and connections, but if you are confident that they are all fine, then it must be the unit itself and we will need to get it back for warranty repair.