Dan, those Spots don't work very well if they are in deep forest -- too little view of the sky. And they pretty much don't work if carried facing forward, like on the front strap of a pack.

Best location is on the top of the shoulder, or on the top of the pack load. They can even be inside some fabric of the pack, but they MUST be facing upward toward the sky. Brett finally moved his farther up and back on his strap, and messages started coming out.

And yesterday, a Spot signal from Brett came in 3 hours late, so the computer network sometimes gets a glitch.