Locating sonde (pipe and duct transmitter)

01

Match frequency, location depth and size to the run

Radiodetection's sonde guide describes transmitting sondes as the way receivers trace non-metallic sewers, drains, ducts or pipes and locate blockages or collapses; special sondes are made for no-dig boring tools and CCTV inspection cameras. The sonde and receiver must work at the same frequency. Its current range shows the trade-off between size and depth: the 39 × 105 mm Standard Sonde, offered at 512 Hz, 8 kHz and 33 kHz, locates to 5 m; the 18 × 82 mm S18 at 33 kHz to 4.5 m; the 64 × 318 mm Super Sonde at 33 kHz to 15 m; smaller units go down to 13 mm, 9 mm and 6 mm diameter for narrow ducts, and a three-section 23 × 478 mm Bendi Sonde at 512 Hz locates to 6 m and is built to pass pipe and duct corners. [1] [2] [3]

The guide lists the Sewer Sonde at 8 m location depth with a 0.5 m minimum and the Super Sonde at 15 m with a 3 m minimum, so a deep-sewer unit can be too strong for a shallow run; the Slim Sonde locates to 3.5 m and its 198 mm length keeps it out of structures with bends. A 910 Sonde from The Charles Machine Works transmits at 512 Hz, passes 90° turns in 76 mm pipe, and is stated for cast-iron as well as non-metallic pipes, with 76 mm as the minimum pipe size. [1] [4]

Radiodetection states that its sondes are not intrinsically safe for use where hazardous gases are present. [1]

Give the supplier the locator model and the frequencies it reads, the pipe material, smallest bore and tightest bend, the deepest and shallowest sections of the run, whether the sonde goes on a rod, camera or boring head, and the thread or coupling it must fit.

02

Plan battery life, pressure rating, couplings and the locate

Battery and pressure figures in the Radiodetection guide: Standard Sonde 190 g, one AA alkaline cell for 20 hours, 2 bar (20 m water); Super Small Sonde 73 g, two CR1/3N cells for 8 hours or, in an extended housing, two AA cells for 60 hours, 2 bar; Slim Sonde 220 g, one AA for 12 hours, 2 bar; Sewer Sonde 500 g, one 9 V alkaline for 15 hours, 0.2 bar (2 m water); Super Sonde 900 g, one 9 V for 5 hours, 0.2 bar. The sewer units send a continuous or pulsed signal, selected by reversing the battery. The 910 Sonde runs 4–6 hours of continuous use at 21 °C on two AA cells, operates from 0 °C to 60 °C, is stored from −20 °C to 80 °C, and loses performance when the total battery voltage falls to about 1.6 V; its cap seals on an O-ring that is inspected and lubricated. [1] [4]

Radiodetection sondes fit M10 male studs; the guide recommends a spring coupling between rod and sonde to reduce shock against the pipe wall and ease the sonde round corners, and lists couplings for drain rods and telecom duct rods. Its Flexrod pushes sondes up to 300 m, with a 250 mm minimum bend radius. The 910 Sonde uses a 3/8 in × 16 thread. [1] [4]

The locating procedure in the guide: fit a fresh battery at the start of the day; as a check, place the sonde at its rated depth from the receiver, blade in line with the sonde, and confirm a reading above 50% at high sensitivity; set the sensitivity to give 60–80% over the sonde; find the main peak and the ghost signals either side of it to confirm the position; then push the sonde three to four paces at a time, pinpointing by moving the receiver along, rotating it and moving it side to side, and mark each position. [1]

Ask for battery type and rated life at your temperature, pressure or immersion rating, signal mode (continuous or pulsed), housing material and seal, thread and coupling, and the receiver modes confirmed to read the sonde.

03

Choose the sonde format

Formats in the reviewed Radiodetection range and the 910 sheet.

04

Coil, battery cap, O-ring and threaded stud

Parts named in the reviewed guides.

05

Frequency, depth and battery hours the job sets

Two fields decide fit: frequency, which must match what your receiver reads, and location depth, which the Radiodetection guide gives as a minimum as well as a maximum for sewer units. Output power, housing material and locating accuracy are not published in the reviewed sources. [1]

06

Send the locator, pipe and job data together

Paste it into your enquiry below or into an email to a maker, then replace every bracket.

Locator: [model; frequencies read]
Pipe: [material; smallest bore; tightest bend]
Depth: [maximum; minimum]
Deployment: [rod type; camera; boring head; thread]
Battery: [cell type; hours needed; temperature]
Environment: [water depth or pressure; abrasion]
Supply: [quantity; spares; documentation]

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