Newbie PLB questions:
Do you turn the unit on before you take off?

If not, how long might it take to boot up and acquire a GPS position fix?

Hypothetical situation: I'm landing out in a bad area, I have no radio contact with anyone, where I think I may get hurt. Can you press the Send Help button and then if you are OK after your dicey landing cancel the send help message you sent out?
I would hate send out the Please Help Me signal, get the system in gear, and then a few minutes later find out I'm OK. I would also hate to crash, get knocked unconscious and not be able to hit the button.. whats the protocol here?