CT-1 SIGNAL INJECTOR
OPERATION MANUAL
2018
JW FISHERS MFG INC
1953 COUNTY ST.
E. TAUNTON, MA 02718 USA
(508) 822-7330; (800) 822-4744; FAX (508) 880-8949
Email: info@jwfishers.com WEB: www.jwfishers.com
Table of Contents
DO NOT......................................................................................................................................................... 3
DO ................................................................................................................................................................. 3
Specifications................................................................................................................................................ 4
Options ......................................................................................................................................................... 4
Introduction.................................................................................................................................................. 5
Theory of operation ..................................................................................................................................... 6
Theory of Operation ................................................................................................................................... 13
Operation ................................................................................................................................................... 14
Test and checkout ...................................................................................................................................... 18
Troubleshooting ......................................................................................................................................... 20
Limited warranty ........................................................................................................................................ 21
2
DO NOT
• Do not touch output posts or cable ends with power turned on (SHOCK HAZARD, IT COULD
BE LETHAL).
• Do not operate if water is on the surface of the control panel or is inside of the Control Box.
Should water splash on the control panel or get inside the Control Box, immediately turn off
the power and unplug the power cord. Water on the control panel, or inside the Control Box,
can be a SHOCK HAZARD AND COULD BE LETHAL.
• Do not let Signal Injector sit in hot sun for prolonged periods.
• Do not plug Signal Injector into any voltage other than 120 vac. Use a 220 to 120 vac
transformer if operating from 220 vac.
• Do not allow the two output clips to short together. It may blow a fuse on the circuit board.
• Do not try to track metal pipes - it will not work. The conductor (the pipe) must be insulated
from ground/water along its length.
• Do not connect the Signal Injector to any LIVE power cable.
• It is the operator’s responsibility to ensure that the cable is not live before connecting the
Signal Injector. Damaged caused by connecting to a live cable is not covered under 2 year
warranty.
DO
• Always turn the unit off before handling the output cable or touching the output posts on
the control box.
• After reading this manual, check out the system using the test cable provided. See test
and checkout in this manual.
• Before connecting the Signal Injector to any cable, ensure the cable does not already
have a voltage applied to it. Check between the cable and earth ground with a voltmeter.
3
Specifications
PERFORMANCE/DESCRIPTIONS:
• Input power – 120 vac
• Power consumption – 10 to 75 watts
• Output voltage – 0 to 150 vac
• Output current – 0 to 500 milliamps
• Output frequency (switch selectable) - 25, 50, 60, 1,024 Hz
DIMENSION/WEIGHT:
• Signal Injector 13” x 12” L x 8” D – 20 lbs.
MATERIALS/COLOR:
• Signal Injector – Urethane, black
Options
• Custom frequencies available
• 220 / 120 VAC voltage transformer for Signal Injector (Europe)
4
Introduction
JW Fishers Cable Tracker Signal Injector is part of a cable tracking system that is specifically designed to
locate and track buried power and communications cables. The complete system will locate cables buried
on land or underwater. The complete system will not only locate and track cables, but also identifies faults
or breaks in a cable. This manual deals with the Signal Injector, a separate manual deals with the Cable
Tracker Probe.
Cable Tracker
Signal Injector
CABLE TRACKER 1 SYSTEM
The Cable Tracker 1 system consists of the Signal Injector control box and the Cable Tracker
Probe. The Signal Injector is attached to an exposed part of the cable on land. A 25, 50, 60 or
1,024 Hz (operator selectable) signal is induced into the cable by the Signal Injector control box. The
operator carries or swims with the Cable Tracker Probe along the length of cable receiving the transmitted
signal. Typically, the lower frequency 25 Hz signal is initially used to locate the cable as it can be detected
from greater distances. Once the approximate location of the cable is determined, the 1,024 frequency is
used to precisely pinpoint the exact location of the cable. When searching for power cables, it is generally
not necessary to use the Signal Injector as the Probe can detect the 60 Hz (USA) or 50 Hz (Europe)
frequency of an AC power line. When tracking live multi-conductor communications cables the 1,024
position is used on the probe to pick up the communications signal (Signal Injector is not needed). The
military and some commercial operations (fiber optics) inject their own 25 Hz tone in a cable for tracking.
These cables can be tracked with the Probe without the JWF Signal Injector. A switch on the Probe allows
the operator to select the frequency to be detected (25, 50, 60, or 1,024 Hz).
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Theory of operation
The Signal Injector is used to create a constant current electromagnetic field around the cable at any of the
selectable frequencies (25, 50, 60, or 1,024 Hz). The Signal Injector (transmitter) is connected to the shore
end of the cable and the Cable Tracker Probe (receiver), which is set for the same frequency, tracks the
electromagnetic signal along the length of the cable.
The amount of current flowing through the cable determines the intensity (strength) of the electromagnetic
field. The stronger the field, the farther away the cable can be detected by the receiver probe. The output
voltage/current of the signal injector is fully adjustable. The higher the Voltage/Current knob is adjusted the
higher the current will be in the cable. Meters on the control panel show the voltage output (0 to 150 vac) and
output current (0 to 500 ma). Once the Voltage/Current knob is adjusted for the desired current, the control
box will maintain that current even though the load may be constantly changing. This current regulation
ensures that the receiver probe gives a steady readout.
Most cable tracking can be done at 75 to 150 milliamps. Deeply buried cables, or heavily shielded cables,
require more current to be detected and tracked by the Cable Tracker probe. As a general rule, use no more
current than necessary to locate and track the cable; it makes pinpointing the cable easier. The amount of
voltage necessary to get the desired current varies greatly depending on the size and length of the cable and
ground conditions. Ground is used for signal return.
The most common frequency used to locate and track non-power cables is 1,024 Hz. The higher
frequency is tuned well away from the 50 or 60 Hz that is common in overhead power lines and
may cause interference. However, if the cable is buried deep, you may have problems detecting it
with the higher frequency so the lower 25 Hz signal is used. If it is a power cable at 50 or 60 Hz
chances are you can detect the cable with the Cable Tracker Probe without the Signal Injector.
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A block diagram of the Signal Injector is shown below.
Power Amplifier Output Signal
Power • Voltage / Current output 0-150 vac
120 vac adjustment
Supply at 0-500
ONLY • Current regulation
milliamps
• Over current shutdown
• Voltage meter
• Current meter
Microprocessor
• Crystal oscillator
• Frequency switch
Earth Ground
7
The Signal Injector contains a main logic board that has three main sections: Power Supply, Microprocessor,
and Power Amplifier.
• Power Supply - Contains power supplies for the internal operation of the Signal Injector plus a high
voltage supply to produce the 0 to 150 vac for the output. The power supply has a fuse on the front panel
and has internal overcurrent protection.
• Microprocessor - CPU monitors the frequency selection switch and produces precise crystal con-
trolled output frequencies to the Power Amplifier section.
• Power Amplifier - Under control of the Microprocessor, the Power Amplifier delivers the current to
the output terminals at the selected frequency. Once the operator adjusts the desired current, the Power
Amplifier automatically maintains the desired current even though the load may change. Each output
terminal has its own fuse on the front panel.
In case of a broken cable, where the broken end is exposed to water, the design of the Signal Injector
eliminates “electrolysis” of the cable end while the system is in use.
The Signal Injector’s AC signal must have a return path for current to flow so the cable can be detected. In
most cases this is accomplished by connecting the red output of the Signal Injector to a conductor (or the
shield) in the cable to be traced, and the black output to a metal rod driven a short distance (if the ground is
damp) into the ground. The other end of the cable (that the red output is connected to) is also connected to
earth ground. A second conductor in the same cable cannot be used as the return path (electromagnetic field
cancels itself out). An interface cable is provided to connect the Signal Injector output to the ground rod and
the cable to be tracked. The interface cable has plugs on the Injector end and alligator clips on the other end.
Jumper
Cable to be tracked Cable
Signal
Injector
Ground Rod
Interface Ground Rod
cable
8
Theory of Operation
The control panel contains all the necessary switches and indicators necessary for operation and control of
the signal injector.
Voltage / 3-amp output
120 vac plug 3-amp Current fuses
(cable provided) main fuse Adjustment
Meter showing
current flowing
in the cable
Meter showing
being tracked
voltage across the
output terminals
Output to cable
Output to
Earth Ground
Power
Frequency Power
“On” LED
selection Switch
switch
The control panel switches and indicators are:
• 120 vac Plug (cable provided) - Input power for the system. Use 120 vac only.
• 3 Amp Main Fuse - The main fuse for the system. Other fuses are inside on the logic board.
• Power On Switch - Applies power to the system.
• Power On LED - Illuminates when power switch is on and Main Fuse is ok.
• Frequency Selection Switch - Selects one of four output frequencies (25, 50, 60, or 1,024 Hz).
• Voltage/Current Adjustment - Adjusts the output voltage/current (which determines the amount of
current flowing in the cable).
• Meter Showing Voltage at Output - Displays the voltage that is present at the output terminals.
• Meter Showing Current Flowing in Cable - Displays the current that is flowing through the cable.
• Output to Cable and Earth Ground - The Interface cable plugs into these two output posts. The other
end of the Interface cable connects to a wire in the cable you wish to track and earth ground.
• 3 Amp Output Fuses – each output terminal has its own fuse.
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Cable to be tracked Jumper
Signal Cable
Injector
Interface
cable Ground Rod Ground Rod
Operation
The only function of a Signal Injector is to inject an AC signal into a cable so that the cable can be tracked
with a cable tracker receiver. The only operational decisions that the operator needs to make is: what
frequency to select, and how much current to run in the cable?
Frequency
• The operator can select any one of four frequencies: 25, 50, 60, or 1,024 Hz. The lower the frequency,
the further it will travel through the ground. For deeply buried cables, or cables that are proving to be
difficult to find, use 25 Hz. The drawback to the lower frequency is that it is a little more difficult to
pinpoint the cable. Higher frequencies (1,024 Hz) are attenuated a greater amount through the ground,
but it is very easy to pinpoint the cable. The higher frequency, 1,024 Hz, is the frequency of choice
for most non-power line jobs. Always start with 1,024 Hz, turn up the power (up to 500 ma) if you
have to.
• When tracking live power lines, at 50/60 Hz, the Signal Injector is not needed. The cable tracker
probe (a receiver) picks up the live power cable. When tracking live multiconductor communications
cables the 1,024 Hz position is used on the probe to pick up the communications signal (Signal
Injector is not needed).
Current
• The Signal Injector is capable of delivering up to 500 milliamps for deeply buried cables. In most
cases 75 to 150 ma does an excellent job. The lower current doesn’t “overpower” the receiver (diver
probe) and makes pinpointing the cable easier. If the diver probe cannot detect the cable then “crank
up the power” until the diver probe is close enough to the cable that it is getting very strong readings.
At that point turn down the power so the cable can be easily pinpointed.
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Return Paths
• Black lead from Signal Injector
• It is important to remember that there must be a return path outside of the cable that is being tracked.
If a separate cable is being used for the return signal, it cannot be close (next to) the cable being
tracked. Always try to use “earth ground” or water for the return path; it eliminates a lot of possible
tracking problems.
Proper setup with correct return paths:
Earth Ground is the return path
OR
Lake / Ocean / River
Water is the return path
Note: Because water is a better conductor than earth ground, water as a return path allows higher cur-
rents to be put in the cable. However, since we need only 75-150 ma for most cables, earth ground
works well in most cases. When earth ground doesn’t do the job because the ground is very dry, a
longer ground rod (deeper in the ground) can help.
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Main Paths
• Red leads from Signal Injector
• The red lead from the Signal Injector is connected to a wire in the cable to be tracked. The other
end of the same wire to be tracked must be connected to earth ground for the return path to the
Signal Injector. Some comments regarding cables to be tracked:
The wire must be insulated from ground along the full length to be tracked.
Earth Ground is the return path
• Metallic pipes cannot be tracked unless they are insulated from ground.
• When a cable, including fiber optics cable, has no wires but has a metal shield, the cable can be
tracked by inserting the signal on to the metal shield. This is done by disconnecting the shield from
ground at the Signal Injector end. For this to work, the shield must have an outer jacket that insulates it
from ground along its length.
• When tracking a broken cable the broken end of the cable must be exposed to ground to have a return
path to the Signal Injector. If the broken end is not exposed to ground, the cable cannot be tracked
(current meter will show zero current).
• When tracking a broken cable, whose end is exposed to ground, the cable can in most cases be
tracked up to 20-25 foot from the break. At that point the return signal is so close to the cable being
tracked that pinpointing can no longer occur. Keep Signal Injector current to a minimum as you reach
the end of a broken cable.
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Operation of the land-based Signal Injector is very straightforward:
• Before proceeding to apply voltage/current to any cable, use a voltmeter to check the cable to insure
that the cable does not already have a voltage on it. You are checking to insure it is a “dead cable”.
After checking for voltage, make an ohmmeter check to insure it is not a dead short between the cable
wire and ground. Even a short cable should measure a few ohms.
• With the Signal Injector turned off, plug the short interface cable into the Signal Injector control box.
The red plug goes onto the red jack and the black plug goes into the black jack.
• Connect the red alligator clip to the conductor (wire) to be tracked.
• Connect the black alligator clip to a ground rod (earth ground).
Earth Ground is the return path
• Select the desired frequency, 1,024 Hz is the most commonly used.
• Turn the Voltage/Current control to minimum (counter clock wise).
• Plug the Signal Injector power cable into 120 vac only. See next page for other power inputs.
• Turn on the Power switch
DO NOT TOUCH THE OUTPUT POSTS OR HANDLE THE ALLIGATOR CLIPS WITH
POWER ON - LETHAL VOLTAGES ARE PRESENT.
• The Power On LED should immediately illuminate. Wait 15 seconds for the Turn On Delay.
• Slowly turn up the voltage while watching the voltmeter and current meter. The voltage and
current should move up together. If you have a general idea of the location where the cable is
running set the current at 75-150 ma.
Note: The more current, the farther you can detect the cable, but the more difficult it is to pinpoint the
cable as you get closer to the cable (it overwhelms the receiver).
Note: The longer the cable, or the smaller the diameter of the wire, the more voltage it will take to
provide the desired current.
Problems
• If only the voltage (no current) goes up (it will max out at 150 vac), then there is not a complete
electrical path for the signal (see above drawing). This could be caused by a poor ground
connection or the cable being tracked is broken and the broken end is not exposed to ground.
This cable cannot be tracked with this setup. Also, one or both Output Fuses could be blown.
• If the current quickly goes to your desired 75-150 ma with almost no voltage shown on the meter,
then the cable is very short, or a short exists at the input connection, or at a very short distance
17
down the cable. Depending on the location of the short determines whether the cable is trackable
to the short.
Input Power
NOTE: The Signal Injector must only be powered by 120 vac. If your input power is 220 vac or 12 vdc, see
below for hookup.
120 vac
120 vac ONLY
Signal
120 vac input Injector
220 vac (optional)
120 vac ONLY Signal
120 vac input Injector
220 vac to 120
vac transformer
12 vdc (optional)
120 vac ONLY Signal
120 vac input
Injector
(12 v battery)
12 vdc to 120
vac inverter
Test and checkout
Before proceeding with checkout of the system, read the Theory of Operation and Operation sections
of this manual. The procedure that follows assumes that you understand how the system works.
Your system was shipped with 100 foot of test wire that we will use for testing the system. If the ground
rods you are using are short they can only be used if the ground is moist. If the ground is very dry then
18
use longer grounding rods or go near the water’s edge where you would normally be working with the
Signal Injector.
Test setup:
1. Stretch out the spool of wire so that the bare end on the spool of wire ends up where the control box
will be.
2. Be sure control box Power switch is turned off.
3. Connect the Signal Injector as shown below.
Earth Ground is the return path
4. Select the desired frequency (1,024 Hz is the most commonly used.)
5. Turn the Voltage/Current control to minimum (ccw).
6. Plug the Signal Injector power cable into 120 vac only. See page 14 for other power inputs.
DO NOT TOUCH THE OUTPUT POSTS OR HANDLE THE ALLIGATOR CLIPS WITH
POWER ON - LETHAL VOLTAGES ARE PRESENT.
7. Turn on the Power switch. The “Power On” LED should immediately illuminate.
8. Wait 15 seconds for the Power On delay before continuing.
9. Slowly turn up the voltage while watching the Voltmeter and Current meter. The voltage and
current should move up together. Check to see that you can adjust to any current from 0 - 500
ma.
Note: If you cannot get the full 500 ma, the most likely cause is dry ground which is a poor conductor
for the return path.
10. Try switching frequencies. You should be able to make the same voltage/current adjustments.
This completes the checkout of the Signal Injector. If you also purchased the Cable Tracker Probe, set the
Signal Injector frequency at 1,024 Hz, the current at 75-100 ma, and test out the probe.
19
Troubleshooting
The Power On LED does not illuminate when the Power Switch is turned on.
1. Check to insure you have 120 vac at the input power plug.
2. Check 3A Main Fuse on control panel.
3. Check 1A (F1) fuse on Main Logic Board.
The Power On LED does illuminate, but the Voltage meter does not go up when Voltage Adjust knob is
turned up.
1. Check the four fuses on the Main Logic Board (see below).
CAUTION: UNPLUG CONTROL BOX POWER. SHOCK HAZARD, IT COULD BE LETHAL
20
Only the Voltage meter goes up (it will max out at 150 vac). The Current meter does not move.
1. There is not a complete electrical path for the signal (see page 12). This could be caused by a poor
ground connection or the wire (that is being tracked) is broken and the broken end is not exposed to
ground. Cables cannot be tracked without current flow.
2. Check the 3A Output Fuses on control panel; one or both may be blown.
Current quickly goes to your desired 75-150 ma with almost no voltage shown on the meter.
1. The cable is very short, or a short exists at the input connection, or at a very short distance down the
cable. Depending on the location of the short determines whether the cable is trackable to the short.
CALL THE FACTORY IF ANY QUESTIONS
Limited warranty
The Warranty on the Signal Injector is for two years from date of purchase and is limited to the electronic portion of
the unit. The Warranty does not include broken, damaged, or lost equipment. Should service be required, contact us
explaining the nature of the problem. Most problems can be isolated over the phone and correct replacement parts
sent to you. In some cases, we may have you return an assembly for checkout. In almost all cases, the Signal Injector
is field repairable.
Should water splash on the control panel or get inside the Control Box, immediately turn off power and unplug the
power cord. Water on the control panel, or inside the Control Box, can be a SHOCK HAZARD AND COULD BE
LETHAL. With the power cord unplugged, lift the control panel and check for water. If there is salt water on the
electronics board, flush the board in fresh water and allow to completely dry outside of the housing. Rinse out the
inside of the control box housing in fresh water if it has been flooded. Do not reinstall the electronics in the control
box. Contact the factory for instructions. See cover page for contact information.
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