Influencer II
You typically see the reception going down in northern width because many services use geostationary satellites that "hover" over the equator or use various iterations of equatorial orbits because 90% of all users are somewhere in the middle and you need lesser satellites, equals cheaper network.Globalstar already has, or claims to have, full coverage of Alaska for SPOT devices. That's why the spotty coverage, no pun intented, for the iPhone is odd. Must be some sort of technical limitation on the iPhone side with how it communicates.
SPOT Satellite Coverage Map | Saved by SPOT | US
www.findmespot.com
So it's not that cut and dried.
Iridium uses polar orbits so you may have blind times but no blind spots in northern/polar regions but the service is more expensive...