scottf wrote:not trying to debate the technologies.. but which layer does that acknowledgement come from? I'll bet in either system there are a quite a number of layers to make make it through before a message makes it to its final destination.
When the sat receives a transmission from an InReach, an acknowledgement of receipt is sent back down the InReach - only then does the message sent indicator light go out. If the message is not acknowledged, it is sent over and over until it *is* acknowledged. If this is a SOS situation, then responders will message you back in an attempt to get additional specific information regarding the emergency.
My experience is that most all tracking points and messages go our immediately, even when the InReach is poorly positioned (e.g. laying horizontal on the pax seat of my car with a poor view of the sky). However, when I was camped at the bottom of a steep Idaho river canyon, a text message I was sending my wife took almost 5 minutes to get out - - poor view of the sky and the InReach had to wait for a sat to come into view. Wife was able to text me back, no problem.
Very cool to be able to stay in touch when there is no cell service for many miles.
bumper