Railmast
er
™
U
ser
’s M
anual
25
The following table shows the effect that an increasing angle has
on a displayed speed .
Horizontal Angle Degrees
Actual
Speed
0° 1° 3° 5° 10° 15° 20° 30° 45° 60° 90°
Displayed speed:
30 mph
30 29 29 29 29
28
28
26
21 15
0
40 mph
40 39 39 39 39
38
37
34
28 20
0
50 mph
50 49 49 49 49
48
46
43
35 25
0
60 mph
60 59 59 59 59
57
56
51
31 30
0
70 mph
70 69 69 69 68
67
65
60
49 35
0
80 mph
80 79 79 79 78
77
75
69
57 40
0
Table 6 .2 .1
Actual and displayed speeds at antenna-to-target angles
Small angles (less than 10°) have little effect on accuracy . As the
angle increases, the displayed speed decreases . At 90°, the target
speed is 0—grossly incorrect .
6.2.2 Fan Interference
Fan interference is the most common form of interference that
you are likely to experience if you operate the Railmaster™ from
the inside of a vehicle . It is caused when the radar measures the
speed of the vehicle blower fan . Changing the fan speed causes a
proportional change in the display speed . To correct this, relocate
the radar gun so it does not display spurious speeds, turn off the
fan motor or operate the Railmaster™ from outside the vehicle . .
6.2.3 Electromagnetic Interference (EMI)
Operating electric motors can produce EMI . EMI from power seats
or windshield wipers can also produce spurious target speeds . To
correct the interference, simply turn off its source .