Why do I sometimes get a 'bad check sum' error when collecting data?

What is a 'check sum'?

Go easy on me, I'm a rook.

This is almost always due to noisy data. Typical causes of noise are:
- moving under trees or near tall buildings
- holding the receiver incorrectly; for example, the MMCE works best when it is held at a 45 degree angle and you should never hold any handheld GPS near your stomach and lean over it as this will block a clear view of the sky.
- working near large electrical fields (industrial air conditions, etc.
- working near radar transmitters (airports, harbors)
Lastly MM Office's post-processing software weeds out bad data automatically in order to achieve the best accuracy. In most cases, the data with "bad check sums" are weeked out and you can essentially forget about them.

And to think JD always told me that meant "you better go back out and check sum points"!

Dangerous Dave