We use XM in Alaska. We as a fishing
fleet have a long history
with XM. Fishermen are very inventive....:-)
Going North does not seem effect the signal. Going west does. About 159 degrees west or 160 west is about as far as the regular antenna's work. Those marine
antenna's are garbage. You have to be able to aim at the horizion. Looking up does no good up there.
The regular marine
antenna's do not work. You have to be able to aim for the horizon. That is the key. We all used the small home units for years. Believe it or not, we got great reception
with a stainless salad bowl behind it. They would last 1/2 a year or so in the Bearing Sea.
XM Radio Home Antenna
We found the amplified ones a lot better. The 1st generation was the PRO500 and we had sealing problems with them. But our antennas are subject to winter Bearing Sea conditions. The PRO600 looks a lot better.
XM Radio Pro 600 Commercial Amplified Antenna
These will work anywhere from the end of the Aleutians to Nome,and anywhere to the east from there.
Do not call XM and ask, the are not allowed to broadcast outside their area.
Hope this helps!