So OK ... always a surprise for me to reconnect radio and 440S and have them initially work well. If you are off shore at all you should have both units interconnected.
Photo of antenna checker showing antenna is tuned well at 1.1 SWR. ~1.5 is good as well as it varies depending on which channel frequency you are checking. 16 is 156.800
Here in RI we can get automated radio check on Ch 24.
Also photo of radio display showing position fed in from GPS.
I keep reminding crew for a Mayday the distress button has to be pressed for 3 seconds.