Ron,

I calibrated a "Loup Sky Speed" this week on a Mid-Tech 6100 controller.  We are getting ready to apply fungicide on wheat and radar has problems with the tall crop.  I ended up with the exact same calibration number that I was using with radar.

The Loup Sky Speed is a device that connects inline with an existing GPS and outputs radar pulses.  I am using it with a Trimble RTK autopilot.  The Sky Speed gets the speed from the VTG GPS string.  I found out that when the Trimble GPS looses RTK lock, it continues to out put the VTG string, but it reports the speed as 0 mph.  So, if I loose RTK lock around trees, the Sky Speed is going to report 0 MPH.  Some times it seems like you can't win.......