Doug,
The move to DC power did nothing. The SkySensor2000-PC equates for elevation related diffraction (but I wonder if its spot on correct).
More testing shows me at elevation of 27 - 55 degrees I see no DEC drift but 1 arc second of RA (too far West = too fast) every 30 minutes. At elevations above 80 degrees the I see less than 1 arc minute of drift in RA (too far West) every hour.
alah - my notes:
http://tech.groups.yahoo.com/group/ss2k/message/7240
http://tech.groups.yahoo.com/group/ss2k/message/7238
http://tech.groups.yahoo.com/group/ss2k/message/7237
Matt