Moving mode tuning fork tests
Moving radar units are designed to acquire a patrol speed and look for target speeds that are faster (opposite
direction) or slower (same direction) than the patrol speed. These two speeds can be simulated using tuning forks.
The two forks are manufactured to vibrate at different frequencies. One fork will be used to simulate patrol speed
and the other target speed. In moving mode, the speed printed on the target fork will not match the speed shown
on the Ranger EZ display. It will be added to or subtracted from the patrol speed depending on the mode switch
selections.
For opposite direction moving mode, the lower speed fork will simulate patrol speed while the higher speed fork
will represent the target. For same direction moving mode, the higher speed fork will be the patrol while the
lower speed fork will be the target.
To perform the tuning fork test, place the radar in Tuning Fork mode and strike the patrol fork (lower frequency)
on a hard nonmetallic surface. Hold the ringing fork in a fixed position two or three inches in front of the antenna
with the narrow edge of the fork facing the antenna. The speed will be shown in the patrol window. While
continuing to hold the ringing fork in place, strike the other fork and hold it next to the patrol speed fork. Both
forks must be vibrating while being held an approximately equal distance from the antenna.
For opposite direction moving mode, the radar should display the low speed fork as patrol and the difference
between the forks as the target speed. For example, for forks marked 35 mph and 65 mph, the patrol would read
35 (low speed fork) and the target would read 30 (high-speed fork minus low speed fork).
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