Just got new In Command 800 installed with the 7500 receiver and we're getting some really bad GPS accuracy.  In the course of a 1/2 mile long row, its drifting anywhere from 8-36".  Rows were planted with Trimble RTK with base station in the same field so they are as straight as it can get.  When leaving the field to go reload the sprayer, (traveling 1/2 mile to the far side of the field), the guidance line will shift between 20-32'...feet, not inches.  It does this on both 133 and 135.  Is there any setting that I need to check?  Is there a history of getting bad receivers?  How about any bad software versions?  The steady steer steering seems to be top shelf but without a valid position, its useless.