18 RD8000 Operation Manual
Section 7. – Locating cables and pipes
This section introduces the principals and techniques of
locating buried cable and pipe utilities with the RD8000
system. For more information on the theory of cable
and pipe location, please refer to
ABC & XYZ of locating
buried pipes and cables
, which is available from
www.radiodetection.com
7.1 Antenna modes
The RD8000 system supports four antenna modes to suit
your particular application or the local environment. These
modes are:
Peak mode.
Single antenna mode.
Null mode.
Peak/Null mode.
7.1.1 Peak mode
Peak mode provides the most sensitive and accurate
mode for location and depth measurement. It provides
a sharp peak response with a corresponding small
decrease in sensitivity. Peak mode cannot be disabled
using the menu.
In peak mode the following indicators are displayed by the
LCD:
Depth.
Current.
Signal strength.
Compass.
To select a peak mode:
Press and release the key to switch the
receiver on.
Press the key until the peak mode icon
is
displayed on the LCD.
7.1.2 Single antenna mode
In Single Antenna mode, the RD8000 will detect with
higher sensitivity over a wider area than peak mode. This
is particularly useful for locating deep utilities quickly and
indiscriminately. Once you have located a target in single
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antenna mode, you should then use Null or Peak modes
to gain a more accurate location as single antenna mode
is unable to pinpoint the location of the target line.
In single antenna mode the following indicators are
displayed by the LCD:
Depth.
Current.
Signal strength.
Compass.
To select single antenna mode:
Press and release the key to switch the
receiver on.
Press the key to select your preferred
frequency.
Press the key until the single antenna mode
icon
is displayed on the LCD.
7.1.3 Null mode
Null mode is used to verify a locate signal in environments
with limited or no electromagnetic distortion.
In null mode the following indicators are displayed by the
LCD:
Signal strength.
Compass.
Right and left arrows.
To select null mode:
Press and release the key to switch the
receiver on.
Press the key until the null mode icon
is
displayed on the LCD.
Null mode gives a null response when it is directly over
the line. The sharp, null response is easier to use than
the peak response but is vulnerable to interference and
should not be used for locating, except in areas where
there is no interference present (See 7.1.4 Combined
Peak/Null mode). In null mode, the receiver will indicate
line position but not its orientation.
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