Found out the other day that a cheap Garmin or other make's of consumer GPS is quite good enough for yield mapping!! you really don't need DGPS for yield mapping!
E-mail me directly and I will give my customers phone n as he has run 97,98 and 2000 R62's with Fieldstar in all of them. He would love to tell you how he compared to a New 2388 and 9610. He put 97 hrs on the 2000 R62 this fall and ran with the others for a week.