Low Frequency Spectrum: 100Hz – 1 kHz

Low Frequency Conductive P/C Locator Overview
Low frequency conductive locators use frequencies usually below 8 kHz, which allows the signal to travel further and locate larger depths than higher frequencies.

Most newer models of utility locators have a frequency mode of 8kHz, and some specific model utility locators have low frequency active (direct connect) modes of 512Hz .

This technology is especially beneficial for locating deep or large diameter utilities. Low frequencies are also less likely to jump onto other nearby utilities, making it easier to trace a specific utility over a long distance. 

However, the lower frequency may also mean a less precise location signal, especially in areas with many utilities.

These locators are capable of finding utilities buried up to 9-30 meters deep.

The use of low frequencies minimizes the risk of signal interference (& signal bleeding) with adjacent conductive utilities, ensuring more precise location. Also, low frequency signals can trace a utilities over much longer distances. 

The limitation and disadvantages is that the signal cannot be used with inductive methods.

It also needs conductive continuity, the signal is effected negatively by low conductivity, breaks, gaps or gaskets, due to the fact the signals low inductiveness or bad grounding.

Low Frequency Locator Technology Q&A Overview.

Can find ferrous objects? Yes

Can find non-ferrous objects? No

Works in silty soil? Possible

Works in clayey soil? Possible

Works in organic soil? Yes

Works in sandy soil? Yes

Min frequency (KHz): Model specific, examples as low as, 0.006 (6Hz), 0.8 (800Hz) and some manufactures have a 512Hz model as the devices lowest frequency.

Available frequencies: Locator Specific, some newer models can have upto 100 custom frequency presets from 100Hz to 999Hz.

Max frequency (KHz): 33 (33,000Hz)~

Effort, training for data interpretation: Low/Med, manufacture training, online course, in-person field training recommended.

Relative cost: Low/Medium ($2500~$3600)

Max depth: 3m/9m-30m~

Specific Applications: Detecting larger pipes and cables over long distance locate jobs. Rural pipelines and utility locating upto thousands of meters.

Specific Utilities that can be located: Can locate metal pipes and non-energized main cables, copper telecom cables, metallic gas pipes

Low-frequency pipe and cable locators are specialized tools designed to locate and trace deep and larger diameter metallic utilities.

These locators are effective because low frequencies can penetrate deeper into the soil and are less likely to stray off (signal bleed) from the target utility, making them ideal for identifying a range of underground services. 

Here are some utilities that can typically be located with low-frequency locators:

Water and Sewage Pipes: Large diameter metallic water mains and sewage pipes, especially those made from materials like cast iron or steel, can be located with low-frequency locators. These utilities are often buried deep to protect them from external damages and to prevent freezing.

Gas Pipelines: Large diameter steel or cast iron gas pipelines that distribute gas across cities or to specific areas can be traced using low-frequency locators. These pipes are buried at various depths, depending on their function and the local geography.

High-Pressure Oil Pipelines: Pipelines carrying oil or other petroleum products are often made of metallic materials and are buried at depths that require low-frequency detection techniques to locate accurately.

Electrical Power Cables: High-voltage power cables, especially those that are armored or have a metallic sheath, can be traced using low-frequency locators. These cables are usually buried at depths to ensure safety and protect them from environmental factors.

Telecommunication Cables: Although many modern telecommunication cables are non-metallic, older or main trunk lines might have metallic components or sheaths that can be detected with low-frequency locators.

Cathodic Protection Systems: These systems are used to protect metallic pipelines and tanks from corrosion. The system itself can often be traced using low-frequency locators because it involves metallic anodes and wiring.

Grounding Systems: Metallic components of electrical grounding systems, such as grounding rods and cables, can be located with low-frequency locators. These systems are critical for electrical safety and are usually buried at various depths.

The use of low-frequency locators is particularly good for deep utility detection, as the lower frequency signals have a better ground penetration capability compared to high-frequency signals.

This makes them suitable for locating utilities that are buried at greater depths, up to about 10-30 meters in some settings, depending on the soil conditions and the specific power of the locator technology being used.

-Direct connection: Conductive methods only (Conductive, the low signal will not work with inductive methods)
-Long-distance: Can conduct a signal trace for km's with the right conditions.
-Low distortion: Due to the low frequency of the signal, bleeding and distortion is heavily minimized.