Hi Bob. I don't know about your coil needs in the snow. But i have a BH 505. I just wanted to know how accurate your depth indicator is. Sometimes mine is right on and sometimes it is way off. Are there certain situations that causes these fluctuations?
Winter is a good time to look for hunting sites seen on old maps. Break out the snowmobile and travel those old forgotten roads watching for foundations or the types of tree/bush growth usually found at old homestead sites.
GPS the site and check it out when the snow melts.