Compass interference

Yes!! It's very irritating!! My phone holster, is near the radio and I get this interference a lot. If I hold the phone away from the radio, it's not as bad but it still occasionally happens.

 

Yep, can't use it in my car at all. I am glad I didn't care about this feature in any way shape or form since the car is the only place it would've ever been useful to me personally

 

Apple says...

I found this on Apple's compass interference page:

"Some areas have more magnetic interference than others. For example, your car's dashboard may have a high level of magnetic interference. If you wish to mount iPhone 3G S on a car's dashboard and use Compass or Maps, do not wave the device in a figure 8 to calibrate. Instead, mount iPhone 3G S, open Compass or Maps, and disregard the message to calibrate. iPhone 3G S will eventually re-calibrate after several turns. Note that it may need to periodically recalibrate while you are driving, depending on the level of magnetic interference present where you have it mounted."

 

And now we know a reason for TomTom's holster/helper.