Originally Posted by
gauvins
Actually, it does show a green light when the system has processed your signal. If you send an SOS, a SAR operation will be launched.
But you are right if you mean that posting your position or sending a canned message may or may not be read and that there is no way of knowing.
(I use a SPOT on a sailboat. Does the job for me. As far as bike touring is concerned, a SPOT messenger is probably more reliable than a smartphone. Phones are more demanding battery wise, and if you travel significantly, roaming fees or local SIM cards will quickly become more expensive than a SPOT subscription)
Sorry, I guess there's some ambiguity there in the word "system". I meant that when a message is sent to the satellite, the satellite does not send an ack ("message received") back to the unit, so you don't know if it really got through or not. I just called SPOT to confirm this; it is still unidirectional, i.e. one way, even for the Gen 3. So you never really know if your messages got through to the satellite or not. Most of the time it probably works, but you never know for sure, which would make me a little bit nervous. The difference with the DeLorme InReach is that it is bidirectional; when it sends a message to the Iridium network, it gets an actual ack back so you know for sure it got through. It can also incidentally send and receive text messages through the same Iridium network, which to me is like having a "satellite phone lite", pretty cool. But also probably more expensive for subscription, so that's always a tradeoff with these things.