[Xringer]

I'm not going to attempt a calibration run in the city. That's something I always do on Rt-3, where it's wide open and the signals aren't blocked by overhanging trees etc.

The error I'm looking for is massive.. I don't think that I'm going to to see it,
unless a part has failed, causing erratic speed displays..
I'm charging up the old DIY-rebuilt Nuvi 350.
It's flip-up antenna and sensitive radio makes it my device of choice for this kind of stuff..