3. Anyone using RockBlock (or another Iridium approach) as a SPOT alternative?
Rockblock is just the modem so you'll need to interface this with something. This is a much better approach that the SPOT as you can then utilise a GPS module that is known to work at altitude such as the Ublox modules and do fancy stuff like 2 way comms. Also you can sub on a month by month basis on this one. However you do need to design a tracker around it.
My thoughts on the Iridium...
I've created a board that integrates an Iridium 9603 with a 32-bit Cortex-M4 CPU and some other bells and whistles, works like a charm, but:
- The Iridium 9603 is much smaller (and lighter) than the 9602 used in the Rockblock, but otherwise functionally identical. The connector used on the 9603 is very small, and very fragile. I wonder how will it would stand up to the rigors of normal handling not to mention the post-burst chaos unless it's very well protected. I've seen at least one or two connectors fail for no apparent reason.
- I wonder how well the antennas for these modules work unless pointed straight up? Not a problem for regular use, but I've heard that some have developed custom gimbals to keep the antenna pointed up.
- In my opinion, it's difficult to get more than 1 packet through every 2-3 minutes due to retries and timeouts associated with failed comm attempts.
- My carrier lets me cancel service at anytime, but it does cost about $20 to activate (Nal Research).
All in all, this Iridium technology is very cool, especially since it lets you do two way communication, and doesn't require use of the APRS infrastucture.
Feel free to contact me off-list if you'd like more information about the boards I've created.