A locating wand, more commonly known as a sonde, is a small low-frequency transmitter built into a camera head or attached to a drain rod tip. The transmitter emits a signal at typically 33 kHz or 8 kHz that is picked up by a handheld receiver on the surface, allowing engineers to mark the exact position and depth of the camera. Sondes are essential for accurate location of defects, lateral connections and points needed for spot repairs. Battery life is usually several hours per camera deployment, and units should be checked before each job. In urban London streets with heavy electromagnetic noise from traffic signals, lighting circuits and other utilities, the operator may need to switch between sonde frequencies to obtain a clean trace.
Locating wand (sonde transmitter)
Transmitter inside a camera head that emits a signal for surface location.
