RIDGID SeekTech ST-305 - Manual (Page 10)

Ridge Tool Company 
Tools For The Professional TM
SeekTech ® ST-305
High Voltage Indicator
Whenever the line transmitter encounters a live voltage on
the line higher than 62 VAC, it will flash a red LED at the top
of the keypad. Should this occur, carefully disconnect the
transmitter using high-voltage precautions.
Useful Information
Resistance and Impedance
Higher resistance reduces the amount of current that can
travel along an underground line. Factors that affect resistance
in the transmitter circuit are conductivity of the line itself,
breaks or faults in the line, insulation problems with the line,
and how well the transmitter is grounded. (Poor grounding
makes the return path of the circuit more resistive).
Grounding can be affected by soil conditions, length of
grounding rod, or how the line transmitter is connected to
the grounding rod. Good grounding improves the signal
by reducing the total resistance the transmitted current
encounters.
Impedance is a form of resistance which is caused by a back-
force in the electrical field caused by alternating current (AC).
Impedance can be thought of as “AC resistance” and adds to
the resistance in the circuit in proportion to the frequency
being used (i.e., higher AC frequencies add more impedance
than lower ones).
Using High and Low Frequencies
High Frequencies:
• Don’t travel as far
• Overcome some barriers
• Bleed-over more
Low Frequencies:
• Travel further
• Lose signal when hitting barriers, gaskets, poor
insulation
Do not bleed-over as much.
As a general rule, detecting with lower frequencies is more
reliable for the reasons given above, IF you can get a good
signal.
Transportation and Storage
Before transporting make sure that the unit is powered OFF
to preserve battery power.
Also make sure that the ST-305 line transmitter is secure
and does not bounce around or get bumped by loose
equipment.
CAUTION: Remove batteries entirely before shipping.
The ST-305 line transmitter should be stored in a cool dry
place.
NOTE: If storing the ST-305 for an extended period of time,
the batteries should be removed.