A recent post to my Blog on my experiences trying to stay connected on a road trip:
"This last attempt to use cellular Internet on the road in this rural area was a lesson in the importance of using a mobile external cellular antenna. I have a 1900MHz antenna mounted on my truck for use with the Sprint EVDO card or the T-Mobile PDA. While using the Sprint card connected to the mobile antenna, I pulled out my Sprint phone to make a phone call. The phone using it's own antenna could not find any service. But the Sprint card connected to the external mobile antenna had an excellent signal and worked perfectly."
Frank Keeney Blog: