This was only the second time in three years my radio picked one up. Pretty impressive alarm sound and then my radio automatically switched to a page of options among which was "acknowledge". I decided to wait to see if the CG responded before doing an acknowledge. I waited about 3-5 minutes --radio silence. I then scrolled to the menu page which keeps a log of the time, position, nature of the alert and MSSI number. Everything was blank but the MSSI and time. I was ready to transmit when the CG finally issued a call that the alarm was determined to be a false alarm. I have a hunch this was coming from Delaware even though I am in NY because all day I was getting CG Delaware Bay on Ch16