Do you have the unit near a window or did you connect the GPS antenna to the cable and place it near a window so it can pick up the GPS satellite signals?
Mine came pre-activated and didn't work until I placed the GPS antenna near a window.
I have a good signal at home, but at work my office is in an area that blocks good signal reception. Sprint was kind enough to comp me the Airwave and monthly fee.
Works great! Sprint is a wonderful company and has always been good to me.
Edit: I received my Airave after calling Sprint Customer Care and explained the poor reception issue I was having at work and how I could not complete a call without dropping connection. After going through all the troubleshooting steps, they recommended the Airwave as a solution and offered to provide it free with no monthly fee (I never even had to ask). It may have helped that I've been with them over seven years and I always try to be cordial and kind when I speak to the representatives-I know how stressful their jobs must be because few people call in to say how much they love their phone or how much they are appreciated for providing support.