Ok, potential retard question coming

So we know this thing can be clipped to your keyring. Can you just turn it on while the keys are in the ignition and expect to get a signal? I always put my gps up on the dash.

Very tempted to get one of these and ebay my telenav unit.

Oh and for the person who asked about telenav - yes, it does do turn by turn directions. When you plan a route, it pulls it from their website. If you go off course, it reconnects and recalculates. Only drawback is if you don't have a phone signal and you go way off course.......