Product Manual

15
Automatic and Manual Output Power
The Rex transmitter delivers power to the "load" that it is connected to. In the conductive
mode, the load is the circuit formed by the cable or pipe being traced, the soil return, and
the ground stake. In the inductive clamp and inductive modes, the loads are the clamp and
the antenna, respectively. The inductive clamp and inductive modes require the maximum
power that the transmitter can deliver. Therefore, the transmitter automatically operates at
maximum power output, and there is no need for manual power adjustment.
In the conductive mode, the power delivered to the load is highly dependent on the external
elements (soil, type of conductor, stake placement, etc.). In some cases, more power is
desired to achieve more distance or depth; in other cases, less power is desired to avoid
bleeding to nearby conductors. Therefore, while in the conductive mode, the user has the
ability to adjust the output power manually, using the front panel controls and visual indicators
described further down in this manual.
Transmitter Current Measurement
When operating in the conductive mode, the Rex transmitter displays the amount of current
flowing into the utility being traced. This is very useful in determining how good of a circuit has
been established by the operator. The circuit can be improved by relocating the ground
stake or improving the metal to metal contact of the conductive clips. A low current reading
indicates a poor trace conductor, poor soil conductivity, or poor ground stake
contact/placement. Higher current readings indicate a better circuit and a better chance at
tracing long distances and deep conductors.
If the current reading is low, try improving the connection to see if the current increases (check
the cables, clips, and ground stake; wet the ground; clean rust or dirt; etc.). Often, the
reason for the low current is the soil itself (sandy or very dry) and/or the conductive quality
and integrity of the pipe or cable that is being traced (cast iron pipes, rusted or broken wires,
heavy insulation to ground, etc.). If an improved connection cannot be made, there may be
a small amount of current still circulating in the circuit. Try increasing the output power
manually and/or increase the gain on the receiver.
Line Voltage and Impedance Measurement
When the transmitter is operating in conductive mode and a new frequency is entered, it
performs an automatic measurement of the AC and DC voltages that are present on the line
to be traced. If the voltage measured on the line is below 5 volts (DC or AC), then the
measurement is transparent to the user and the transmitter proceeds to transmit the desired
signal onto the line. If the voltage is above 5 V (DC or AC), an UP ARROW will be shown on
the LCD display and the buzzer will be turned on to warn the user of the presence of voltage
on the line. The transmitter will continue to retest for the presence of these voltages until they
fall below 5 V, in which case it will resume normal signal transmission.
To determine the type (AC or DC) and value of the voltage present on the line, and to measure
the line impedance, the transmitter can be put into the Measurement mode by
simultaneously pressing the Frequency and Output Power controls while in the conductive
mode.