Thanks, Kurtz! Yea, the satellite sets the time automatically. I've traveled (Florida to California) with this unit and it automatically corrects the time for each time zone. Don't know why it would give you the option to change it. I mean, if anyone should know what time zone you're in, it's the satellites, right?

 

The satellite has no idea where you are...your GPS does.

The satellite knows what time it is in UTC (coordinated universal time).

The GPS then uses its time zone and DST info to translate that to the correct local time.

Now, I agree the GPS can use your location, and the date, to make its best guess about the right local time, and it'll usually be right... but being able to manually control DST and time zones can be useful for several situations:

1) They changed when DST started fairly recently... if you didn't update your GPS software for this change your local time would be an hour off for a few weeks if you couldn't change it manually

2) Time zone/DST stuff is controlled locally somewhat... and I doubt the GPS software is programmed with every little quirk of local rules, or updated everytime they change... for example in Arizona they don't observe DST at all... except on a large indian reservation in AZ they DO observe it.


So, most of the time, letting the GPS do it all automagically will work great... but it's nice to have the option to manually change things too for those weird circumstances it'd be useful.

 

Thanks for that tip. That's what i've been trying to do to my navi but couldn't figure out.