Anyone have any ideas on this? A little experiment in the car with iFly 720:
With the unit on the seat, it takes forever (read: I give up after 15 minutes) to acquire a lock. If I bring it up to the windshield, or connect an external antenna by the windshield, it quickly acquires.
Once acquired, the unit stays locked fine from there on (~strong 3-4 bars) on the seat without external antenna. That is, it is receiving satellites fine while laid on the seat.
So: is greater signal (SNR) needed for initial acquisition? If so, why? By the way, this behavior occurs after the unit was successfully used the previous day, so it is not a large (many miles) position change.
Thanks,
--Josh