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or 22Hz LED but an audible tone can be heard, in this case care should be taken in
interpreting the audio signal.
4.
Keeping the antenna parallel to the pipeline move slowly and methodically up and down
the pipeline while listening to the received signal and watching the 3002RS display to
determine what direction gives the strongest and clearest signal. Keep moving in this
direction until a peak in signal is received which will occur at the approximate position of
the transmitter.
5.
If the signal is strong and clear then it should be possible to find this peak by following the
line keeping the antenna as still as possible and possibly reducing sensitivity. If the signal
is weak and difficult to detect without high sensitivity then it is usually best to periodically
place the antenna stationary on top of the pipeline at 2m intervals to prevent false signals
caused by movement of the antenna. The 2m interval may be increased or decreased
depending on whether a strong or weak signal is expected.
6.
Methodically readjusting sensitivity can help to achieve the clearest received signal.
7.
On reception of a true 22Hz signal, the 22Hz LED will illuminate, the 22Hz asterisk will
appear on the display and the bargraph and audio tone will give an indication of the signal
strength. When trying to detect a signal a combination of all of these outputs should be
monitored.
8.
When a continuous 22Hz signal is detected for more than 3 seconds continuously the 22Hz
event counter will increment. The 22Hz event counter can be reset by pressing the
BATTERY TEST/RESET or by turning the 3002RS OFF. The 22Hz event counter cannot be
used reliably with transmitters configured in pulsing mode.
9.
Once the approximate transmitter location has been established refer to section 3.5
ACCURATE TRANSMITTER LOCATION if a more accurate location is required.
3.5. ACCURATE TRANSMITTER LOCATION
1.
Establish the approximate transmitter location as per section 3.4 APPROXIMATE
TRANSMITTER LOCATION before attempting to establish a more accurate location. The
perpendicular antenna orientation used to establish the accurate transmitter location is not
suitable for searching for the approximate transmitter location due to the relative
insensitivity of this orientation.
2.
Once the approximate location of the transmitter has been
determined
turn
perpendicular to the transmitter and pointing at its centre
as shown. Typically the antenna should be held stationary
approximately 1m from the pipeline surface however this
distance may need to be reduced or increased depending
on how weak or strong the received signal is respectively.
3.
Adjust the 3002RS sensitivity until the bargraph shows a
received signal of approximately half scale. Move closer to
the transmitter if required.
4.
Maintain the separation and orientation and slowly and methodically move the antenna
along the pipeline in either direction from the approximate transmitter location. The
received signal should drop significantly as you pass the inherent 'null spot' of the
transmitter which occurs when the perpendicular antenna is pointing at the centre of the
transmitter. Moving just a few centimetres ahead or behind this point will cause a
relatively large and sudden increase in signal.
3002RS_5002_A01
the
antenna
90°
so
that
it
is
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