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IGITAL
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ONTROL
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NCORPORATED
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DigiTrak Falcon F5® Operator's Manual
What is Interference?
Interference can reduce the transmitter’s range or cause variable readings and possibly result in job
slowdowns. Interference is classified as either
active
or
passive
.
Active interference
, also known as electrical interference or background noise, can have varying effects on
locating equipment. Most electrical devices emit signals that can inhibit the ability to locate the transmitter
accurately or get good roll/pitch readings. Example sources of active interference include traffic signal loops,
buried dog fences, cathodic protection, radio communications, microwave towers, cable TV, fiber-trace
lines, utility data transmissions, security systems, power lines, and phone lines. Interference at the remote
display may also occur from other sources operating nearby on the same frequency. The following section
describes how to use the receiver to test for the presence of active interference.
Passive interference
can reduce or increase the amount of signal received from the transmitter, which
results in incorrect depth readings, a completely blocked signal, or locates in the wrong position. Example
sources of passive interference include metal objects such as pipes, rebar, trench plate, chain-link fence,
vehicles, saltwater/salt domes, and conductive earth such as iron ore. The receiver cannot test for the
presence of passive interference. Conducting a thorough site investigation prior to drilling is the best method
of identifying passive interference sources.
To familiarize yourself with the interference potential along your intended bore path, check for background
noise as discussed in the following section.
A receiver cannot detect sources of passive interference; this can only be accomplished with a
visual inspection of the jobsite. A background noise check can only find
active
interference.
I thought the Frequency Optimizer did all this for me?
The Frequency Optimizer finds the lowest-noise frequencies to use in each band. You choose
which bands to use and pair the transmitter. As best practice, now test those bands above ground
to ensure the receiver can receive data for the entire length of the bore. A good background noise
check is vital to a job free of interference surprises.
Checking for Interference
Ensure the receiver is on, optimized, and paired. Remove the batteries from the transmitter to turn it off and
wait 10 seconds for it to fully power off. Now walk the intended bore path while viewing the current frequency
optimization in the frequency band you intend to drill with. Take note of the bar graph height in the selected
band. With no transmitter on, this “signal strength” is in fact background noise (active interference). Extreme
background noise (interference) may cause signal