Freedom GPS Puck vs Blueant ST3

Not sure if this is a GPS issue or an overall Bluetooth problem.

Here is my issue: I have TMO Curve 8320 with the first generation Freedom Keychain GPS puck. I have a blueant ST3 hands free speaker as well. The connection to the GPS is dropped if I receive a call on the ST3. Is there a solution to this problem? I know I read about this problem a while back, but this was before I had the ST3. I couldn't find the thread with a search either. Does anyone have this same issue? Going on a road trip tommorow to a place I've never been and my family is already there. I'm certain I'll be on the phone with them on my way out.