XM Radio Reception Issues
 

I have a 2011 Tucson, and am nearing the end of the XM radio 90 day trial. They have offered me a 3-month renewal rate of 5.99/mo.
I have found that my radio cuts out on both of my commonly used routes - to shopping: for a stretch of about 2 minutes there is no signal at all, and to work: I lose signal for 20 seconds, followed by several minutes worth of minor cut outs (to light static, with the music being lost).
I just assumed that there was no satellite reception in these areas, and figured that xm was not for me. However, the other day I was discussing this with several of my colleagues at work, and they said that, yes their xm cuts out on the way to shopping, but no, theirs do not cut out on the way to work. (They both have factory installed xm, on a Cruze, and on an Equinox)
Is it possible that my reception is not as good as theirs? Is there a way to 'boost' the built-in xm signal?
Has anyone else had reception problems? Any solutions?
Thanks!