KenK has it pretty much correct.

The issue with a "view to the south" is like so much regarding these beacons, confusion by those who don't understand the system.

The Geosynchronous satellites orbit directly over the equator. Due to curvature of the earth, they are only viewable from about 70 degrees north to 70 degrees South. So, as you move higher in latitude, the Geo at is lower on the horizon, south or north depending on your location. Geo sats provide pretty close to immediate alerting and if you have a GPS location, location as well.

Regardless, the Low Earth Orbiting, LEO, satellites, will eventually come overhead enough to get your signal, anywhere on the planet that has at least some view of the sky. Depending on where you are relative to the orbiting satellites this alert could be immediate or up to 1.5 hours delayed. In North America, typically no more than 45 minutes and usually much less. The LEO stas also provide a Doppler location that Ken talks about, even without GPS.