Absolute Signal Strength
The 8879 R
ECEIVER
provides the operator with a direct measurement of the R
ECEIVER
’
S
signal strength. The
measurement is displayed with three numerical digits (ex:
485
) located at the top of the LCD display. The
measurement range is from 0 to 999 indicating a very week signal (0) to a very strong signal (999). Absolute
Signal Strength is independent of the GAIN setting or meter reading. It gives the operator information about
the actual amount of signal being radiated from the conductor and received by the R
ECEIVER
.
Measuring Absolute Signal Strength at any time is done by reading the number at the top of the LCD dis-
play. The Absolute Signal Strength will not be displayed if the meter reading is too high or too low. Adjust
the GAIN to move the meter reading to mid-scale. The numerical display will change from
‘---’
to a valid
measurement.
Absolute Signal Strength measurements are more sensitive to signal changes than the meter display.
PEAKS and NULLS can be more precisely pin-pointed. This measurement can also be used to monitor sig-
nal loss as the conductor is being traced.
The 8879 R
ECEIVER
contains a feature that is very useful in identifying a desired cable in a field of various
conductors and/or utilities. It is not unusual for the target conductor (the conductor connected to the trans-
mitter) to induce a signal into nearby conductors in a crowded field. In these instances, the radiated signal
on the conductors close to the surface of the earth, may be stronger than the T
RANSMITTER
signal on the
target conductor buried deep in the ground. The operator will find two or more paths and must determine
which is the target conductor. By using the current measurement feature of the 8878 R
ECEIVER
, the opera-
tor can determine the amount of 815 Hz, 8 kHz or 82 kHz current flowing on the conductors, regardless of
the depth. The highest current flow indicates the target conductor.
Begin this measurement by locating the path of the cables to be compared. Mark these locations as accu-
rately as possible (see the sections on Peak Mode Locating and Null Mode Locating). Place the R
ECEIVER
vertically over one of the conductor marks and rest the foot of the locator on the ground. Holding the
R
ECEIVER
vertical, press and release the CURRENT button. When the meter changes from a “thermome-
ter” type display to a “bar” type display, hold the R
ECEIVER
still until the measurement stabilizes. The blink-
ing bar indicates the signal level on the cable (adjusted for depth). Next, move to the second cable and
repeat the measurement. The blinking bar will show the signal level on the conductor. In addition, the pre-
vious reading is shown as a solid bar. The higher of these two readings will show which conductor is car-
rying the greatest locating signal.
Current Measurement
Note:
The 8879 is designed to alert the operator of potential current measurement errors. If the display reads
‘Err’
during a current measurement, the R
ECEIVER
has detected a condition that could produce inaccurate
readings.
Errors can exist when the conductor signal flow is too small. Check T
RANSMITTER
hookup and far end access
point for poor connections. This cause of error can be identified by a high GAIN setting (80 or greater on
the bargraph display).
The R
ECEIVER
may also be detecting adjacent cables or is not directly over the target conductor. Verifying
target conductor path precisely before measuring current again.
If at anytime the display reads
‘CAL’
, contact RYCOM.
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