User Guide

8
3
Automatic Mode
In the automatic mode, the receiver operates with a minimal amount of input or interpretation from the operator. The oper-
ator simply follows the Left/Right guidance system. The operator can choose to display the locate information in either the
Peak or Null modes depending on preference. The On-Off/Volume/Sensitivity Control is used only to adjust the loudspeak-
er volume in the automatic mode.
While locating, the display provides three different pieces of information to the operator. First, the instrument tells you
which way you need to go, left or right. The pitch of the tone played by the loudspeaker will also change from left to right.
A down arrow will be displayed when the receiver is directly over the line under test. Second, the instrument has a three
digit numerical readout (0-999) on the LCD. This provides absolute signal strength in the automatic mode and is used to
compare signal strength from one utility to another. This comparison should occur when the down arrow is displayed.
Third is the bar-graph display. The bar-graph on the LCD simulates the result you would see from an analog panel meter.
IN THE AUTOMATIC MODE, LEFT/RIGHT GUIDANCE ARROWS WILL POINT TO THE DIRECTION OF THE TARGET
LOCATE. AT THE EXACT LOCATE, A DOWN ARROW WILL APPEAR. WHEN THE DOWN ARROW IS PRESENT, THE
LEFT/RIGHT GUIDANCE ARROWS AND THE SOUND FROM THE SPEAKER WILL NOT BE PRESENT.
Peak Mode - Automatic
The bar-graph display will build up as you approach the line, and "peak" as you cross it, and then roll off on the other side.
The guidance arrows will change direction as you cross the line, the tone pitch will change and you should also see the high-
est absolute signal strength number. These four things should all correlate with each other. In the peak mode, the receiv-
er must be at right angles to the direction of the conductor's path.
Null Mode - Automatic
The bar-graph display will be high as you approach the line, and sharply drop off as you cross it, and sharply increase on
the other side. The guidance arrows will change direction as you cross the line, the tone pitch will change and you will see
the highest absolute signal strength number.
Absolute signal strength will not change between peak and null modes. It is strictly the amount of raw signal the instru-
ment is seeing on the line.
WHEN LEFT/RIGHT GUIDANCE ARROWS ARE PRESENT ON THE DISPLAY, THE RECEIVER MUST BE AT RIGHT
ANGLES TO THE CONDUCTOR PATH FOR BEST SIGNAL READINGS ON A LOCATE.
WHEN MAKING A LOCATE IN THE AUTOMATIC MODE, IF THE DOWN ARROW CANNOT BE FOUND, OR THE DOWN
ARROW DOES NOT AGREE WITH THE BAR-GRAPH READING, THE RECEIVER IS TELLING THE OPERATOR IT IS PICK-
ING UP A DISTORTED RADIO WAVE AND THE LOCATE COULD HAVE AN ERROR IN ITS POSITION.
Low Signal-Automatic
The Digi-7 receiver continuously monitors the absolute signal strength present on the conductor under test. If the signal
level drops below 260 on the display, the low signal flag will begin to flash. This is a warning to the operator that signal is
getting low and something must be done with the transmitter to improve signal strength if a longer trace is needed. At 230
and below, the direction arrows will also flash along with the low signal flag. At this point, the locate may be unreliable. If
the locate is not finished, something must be done with the transmitter to increase signal on the line being traced.
NOTE: If the receiver is switched to the manual mode, the tracing range will be extended.
INDUCTIVE TRACING
Set the transmitter directly over and in-line with the conductor to be traced. The "CONDUCTOR PATH" decal should be over
and in-line with the target conductor. Turn on the transmitter and set the power control to low power. More power can be
used, but low power will help reduce signal being applied to other utilities that may be in the same area.
On low power, the operator should be 20 feet in the manual mode and 30 to 35 feet in the automatic mode from the trans-
mitter before a locate is started. The transmitter is radiating signal in all directions and operating too close to the trans-
mitter could produce a transmitter locate rather than the target conductor locate. The receiver can now be used to locate
the conductor path in either the null or peak method.
If the locate requires an inductive trace at less than 20', set the receiver to MANUAL PEAK. Make the locate and mark it.
Now set the transmitter at a 45° angle on the target line instead of in-line with it. Go back and check the locate. If the locate
is no longer present, it was probably the transmitter that was being located instead of the target conductor.
TRACING WITH THE INDUCTIVE COUPLER
To use the Inductive Coupler, the line being traced must be grounded at both ends. This ground can be through a load of
some type like a transformer winding to the ground rod. The circulating signal from the Inductive Coupler must travel from
one end of the conductor to the other end through the earth and it cannot do so unless both ends are grounded.
The Inductive Coupler plugs into the direct output phone jack on the transmitter. The transmitter will automatically set up
tap # 1. This is the correct tap and should be selected if the transmitter is operating in the manual mode. When a phone
plug is installed in the direct output phone jack, the Inductive Antenna is now disabled out of the circuit so the receiver can
be used very close to the transmitter.
When using an Inductive Coupler, it should always be used around the outer sheath of a telephone or CATV cable before the
sheath bond breaks out. It can also be placed around the service drop at the house without removing the house protector
cover. A coupler can also be placed around a plastic or metal duct as long as there is a conductor inside the duct.
For best results, the mating parts of the Inductive Coupler core material should be free of dirt or contamination at all times.
Some limited range may be obtained if the coupler is not closed, but maximum tracing range will require the coupler to be
completely closed with both sides of the core material touching each other.
CORRECTING FOR A BROAD PEAK READING
When using an Inductive Coupler or the Direct Output mode of tracing, there may be times when a wide or broad peak read-
ing is found near the transmitter. If this occurs, the receiver is being flooded with too much signal. Reducing the signal on
the line being traced can be accomplished by setting the transmitter to Manual Mode and the tap switch to number 4 or 5.
This will be the wrong impedance tap for a long or deep trace, but the reduced signal will un-flood the receiver and a sharp
crisp peak reading can be found near the transmitter.
Figure 7