Electromagnetic Locator

The paired transmitter and receiver that is the workhorse of utility locating. The transmitter puts a signal on a conductive line and the receiver traces the electromagnetic field radiating from it.

An electromagnetic locator finds metallic pipe, cable, and tracer wire — anything that will carry a current. It cannot find plastic pipe with no tracer wire and no accessible end, which is the single most important limitation in the trade and the reason a GPR cart rides on the same truck. Depth readings come from the field shape rather than from a direct measurement, so they degrade wherever the field is distorted. Most locators offer several frequencies, and choosing between them is a real skill: higher frequencies couple onto poor conductors more easily but also bleed over more readily.