SPOT uses Globalstar. Argument against Globalstar is that it is not a true polar to polar real-time solution like Iridium. Iridium is the only constellation w

SPOT uses Globalstar. Argument against Globalstar is that it is not a true polar to polar real-time solution like Iridium. Iridium is the only constellation where you will always find a bird overhead anywhere on the globe (with a ground station relay) Realistically, Iridium has occasional (~5min) signal gaps likely due to the aging constellation (based on my own use cases developing with a roof mounted antenna)