Kustom Signals Golden Eagle II Operator's Manual page 65

NOTE: Minimum ground speed displayed is selectable
at either 10 or 20 MPH (16 or 32 km/h). To check
the setting, press the PAT/SEL switch while the
radar is not locked. The TARGET window will
display "PAt", the PATROL window will display
either "10" or "20". To change the setting, press
the MODE switch once while the "PAt" "10" or
"20" is being displayed. The unit will
automatically return to normal operation after 2
seconds.
Operating moving radar in the rain, fog, or snow requires
the operator to pay close attention to the patrol speed.
Since rain, fog and snow may affect the ability of the radar
system to find groundspeed, the operator must verify that
the radar's patrol speed and the patrol vehicle's speedometer
agree within allowable limits.
Section 8—Interference
8.5