Isolating lines and Nulling out adjacent conductors
ISOLATING LINES AND NULLING OUT ADJACENT CONDUCTORS
The trick is to maximize the signal on the target while minimizing the signal applied to any adjacent conductors.
Below are a few of many techniques that can get you through some tough spots. If they don’t work for you, give us a call at 800-952-3710. We can help you with the best techniques for your specific application.
Conductive Locating (Directly Connected)
– Improve your grounding situation by:
- Ground away from trouble. Stretch the leads 90° to the run of the conductor as far from adjacent conductors as possible
- Do not cross adjacent conductors with your leads
- Increase the ground surface area and/or depth
- Wet the area around the ground stake
– Be sure your connection points are good metal to metal contact (no paint or rust) and that you are below any insulators.
– If authorized, disconnect any common bonds.
– Use a double-ended transmitter connection. Connect to the target as usual at an access point, then ground via a long wire to the target at another access point farther down the direction you want to locate.
Using a Signal Clamp
If you can’t directly connect to the target, another way is to use a Signal Clamp with the 800 series transmitter. If using the 800-HL or dual frequency transmitter, both frequencies are emitted from the clamp. The clamp will induce the majority of it’s signal(s) onto the conductor(s) that it is clamped around, thus minimizing the signal on the adjacent conductors. This gives you more options for finding the target conductor.
Inductive Locating w/ High Frequency
If you have a place to hook up to, connect a wire to the target conductor and lay it out perpendicular to the other conductors. Place the transmitter on the wire, a few feet from the end. The wire acts as part of the conductor and in that position the transmitter will put a much stronger signal on the target conductor vs. the adjacent conductors.
In a lot of cases you can simply move the transmitter slightly to the opposite side of an adjacent conductor. This puts a slightly weaker signal on the target conductor but also significantly weakens the signal put on the adjacent conductor.
If there are two lines causing confusion you can place the transmitter on its side in “null” position over the unwanted conductor. This will put a signal on the target conductor and make the unwanted adjacent conductor nearly disappear.