True, Onstar uses max power versus the low power for a hand-held cell phone. I had no problems using the cell phone on my Onstar anywhere I used it while on my trip to Moab. Even in areas where there appeared to be no cell phone coverage per my (and my son's) Verizon cell phone, I was able to connect via onstar. Possibly I was roaming into analog areas, and our cell phones were only dual bands with no analog roaming.
I had to use up 100 minutes I purchased before adding my Onstar to my verizon account; now that they have finally figured out how to allow this with a GM discount in the MI area.
