2-12. Noise and walk test
system should be operated at the lowest RANGE control
setting that will give the required coverage. Operating
The noise level test and the walk test must be
the system below its maximum capability can result in
performed for each transceiver location. The noise
more consistent performance. Maximum efficiency in
level test checks out the adjacent turbulence and the
surveillance detection is obtained by adding another
walk test verifies the intended surveillance coverage.
transceiver to extend the range of a system rather than
stretch the existing system to its limits. Under no
All tests should be
conditions should the noise test exceed more than 0.15
conducted in the worst case situation with background
Vac when there is no human motion is any of the
turbulence at its maximum anticipated level.
protected areas. Prior to the noise test and the walk test
conditioners, heaters, and machinery that would
for each transceiver perform the following adjustment
normally operate during the hours that protection is
and multimeter setting.
required should be turned on.
The only human
movement within the protected area should be that of
Set the RANGE control(s) of the
the walk tester.
transceiver(s) to coincide with the condition as listed in
As a general rule, the
Table 2-2. Typical RANGE settings for varying number of transceivers.
(2) Set the multimeter (AN/USM-210) to
read A.C. and the range selector switch to 2.5 V.
c. Location Test. The transceiver location is now
(2) If the multimeter reads greater than
ready to be checked for noise level and to be walk
0.15 Vac, check to see the cause of the major
contribution to the noise turning off air moving units,
heater and machinery one at a time and observe the
(1) Apply power to the processor and allow
noise level on the multimeter. If necessary, reduce the
to stabilize for approximately 30 seconds.
RANGE control setting to a noise level of 0.15 Vac or
reposition the transceiver to a different location of a less
noisy or turbulent area in the room that is being
Each time power is applied to the
processor a stabilizing period of
(3) Walk through the entire area covered by
approximately 30 seconds must elapse
the transceiver and verify its adequacy in detection.