Radiodetection RD4000T10, Руководство пользователя

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RD4000 Locating System User Manual
Page 31
Depth measurement will not be accurate if there is audible interference or if part of the transmitter signal has
coupled to a nearby line.
Confirming the peak position coincides with a null position indicates that the position is suitable for making a
depth measurement.
•
Pinpoint the target line accurately with the receiver
•
Check the receiver is directly over the line, the antennas are at right angles to it and the receiver is vertical.
Adjust sensitivity level to bring the bargraph indication on scale
•
Press the depth measurement button and read the depth from the receiver display.
If the ground appears to radiate a strong field, perhaps near a radio station, check depth by holding the bottom
of the antenna 5cm/2in above the ground and subtract this measurement from the indicated depth.
Verifying a depth measurement
Check a suspect or critical depth measurement by lifting the receiver 0.5m/18 inches above the
ground and repeating the measurement. If the measured depth increases by the same amount it is a good
indication that the depth measurement is correct.
Depth measurement should be accurate to +/-5% if conditions are suitable. However, you may not always know
if the conditions are suitable so the following techniques should be used to check critical readings:
•
Check that the route of the line is straight for at least five paces to either side of the measurement point
•
Check that the signal response is reasonably constant over the ten paces length and make depth
measurements to either side of the original point
•
Check that there are no adjacent lines carrying a significant signal within three or four paces of the target
line. This is the most common source of error of depth measurements as a strong signal coupled to an
adjacent line can often int/- 50% error
•
Make several depth measurements at points slightly displaced from the line’s apparent position. The
shallowest indication will be the most accurate and will also indicate the line’s position most accurately.
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