Some really good questions and comments on this thread about
http://www.406Link.com that I think I can help with. I actually work with ACR and manage the 406Link service so let me help clarify a few things.
How are we doing it? We have 2 ground station LUTs (local user terminals) that are actually listening to the GEO11 and GEO12 Satellites (Cospas-Sarsat Satellites) which cover all of North and South America and reach as far west as New Zealand and as far east as Western Africa. When you perform a self test we get your message from the Cospas Sarsat satellites and our software routes it to the email and SMS text message you set up to send "I'M OK" message.
Battery Life is a big question we keep getting asked. ACR PLBs have the capability to do around 420 self tests over the life of the battery before the battery witness seal is broken and this feature is disabled so that you do not start using the required 24 hours of emergency life remaining in the battery. This ensures that in an actual emergency you will still have enough battery life to be rescued. Our new SARLink and AquaLink PLBs can also send GPS coordinates through
http://www.406link.com, these are limited to 12 GPS tests with the basic model and 60 GPS tests with the new View models (that also sport an awesome new digital display). We put a hard count on these GPS tests as they use up more battery than a normal self test.
The other big question I get asked all the time is “Will it work with my PLB or EPIRB?” The service will work with all 406 MHz ACR PLBs and EPIRB and most of our competitors. If you have a PLB that has an external antenna that can be deployed your beacon will work with our system. The only beacons that we know will not work with
http://www.406Link.com are PLBs that have a single use antenna that is wrapped inside of the beacon and are only deployed when you activate the beacon (such as the McMurdo FastFind PLBs).
The service is not a bread crumb tracking service, it is an added way to send some peace of mind back home to let your friends and family know you are ok and everything is fine. I have been using it for the past two month and my family is really thankful. On hunting trips I send an I'm ok message when I get to my stand and another at the end of the day so they know everything is fine. If I'm running late and don't want them to worry I send another I'm ok message.
The response time to receive our "I'm Ok" message once you perform a self test is around 30 seconds from the completion of the test. With our new PLBs that can send GPS, this test typically takes less than 2 minutes to download your coordinates and another 30 seconds to reach your cell phone. It really is impressive especially considering the message is traveling 22,000 miles into space and 22,000 miles back to earth.
If you have a PLB and want to give it a try we have a free 2 day trial on our homepage that doesn't require any credit card or payment, it’s absolutely free to test your beacon out.
Hope this helps guys.