After finding 19 caches, I'm begining to wonder if my base model e-trex (yellow) is working OK. With more time in the field I've noticed a couple things. If I stand in one spot, the go-to arrow sometimes moves around. If I stand in one spot, then move say 100 feet away and come back to the same spot, should my e-trex coordinates be exactly the same? I know the accuracy is about 20 feet. Am I expecting too much? Thanks!!