I posted a similar topic on the garmin forums, but knowing that many of you use garmin products, thought I would try it here as well. The hr strap for my garmin 305 is giving me high hr readings when it is not strapped on. When I take the battery out, it stops registering, but when I place the battery back into the strap, it begins to climb up until about 240 beats. All meanwhile not strapped to anyone. Any idea what the cause of this is? Thanks again.