Position Options - Datum is incompatible with paper map and GPS

Former Member
Former Member
Hi I am using a Swedish topo map BD4 with a grid = SWEREF 99 TM and a datum = GRS 80.

My Etrex10 defaults to GRS80 when SWREF99 is selected.

However Basecamp defaults to datum = ETRS89 when the SWEREF99 is selected and does not allow any other selection.

If anyone can help with updating the grid / datum options this would be appreciated. Or a viable workaround.