Satellite radio - First steps in diagnosis

Signed up for a trial of Sirius Satellite Radio. Not generally receiving any signal. Every once in a while (maybe once or twice per hour), will receive about 5-10 seconds of audio. Called Sirius several times, and they sent "refresh" signals. Didn't make any difference.

Have traveled over 1000 miles, all over the Western half of the USA, at every imaginable altitude, and in wide open spaces. Nothing seems to help.

What are the first steps in diagnosing the issue?