By the way, I tested this unit(XGPS150A), works fine. I disconnected the external GPS while in air. The iPadwas not able to get GPS signals with the internal antenna, within 2-3 minutes,so I connected it back on and was right back on my position.

One thing to note was that SD reported about30-40 feet higher altitude then my Garmin. Don't know why or which is correct(if any of them are, who knows?)