3M 2273M-iD, 2250M-iD manual One-person Active Induction Mode Sweeps

ground. Other passive sources exist, such as Cathodic Protection, LF and CATV cable (with NTSC TV CRT turned on).

Walk in a grid pattern over the sweep area holding the receiver as shown in the following illustration. Stop when there is a response increase, locate the position of the maximum signal, follow the conductor path all the way out of the sweep area while putting location marks on the ground. Resume the sweep until another cable or pipe is detected, or the whole area is completely swept. Switch to another available passive frequency in the receiver and sweep again.

D. One-person Active Induction Mode Sweeps

One-person active induction mode sweeps require that the transmitter be set on the ground over the suspected path of the buried infrastructure. The receiver is used to detect signals induced by the transmitter on buried long conductors. Proper placement and orientation is key to maximize the induced signal in the buried cable or metallic pipe enough to be detectable by the receiver along each path in the swept area. (Note that no signal is induced onto a conductor whose path is perpendicular to the Induction Direction indication.)

•Place the transmitter in the upright (bottom on ground) position for directional optimization when aligned with the Induction Direction shown on the label on the transmitter.

•Tip the transmitter over towards the front, and lay it on it's front surface, for multi- directional wide area induction. (Note that no signal is induced onto a conductor whose path is directly under the transmitter).

•Remove anything plugged into the Output Jack [T-6] (this will place unit in Induction Mode), select highest available frequency (200 kHz) and highest output power level.

•Select the Induction Peak (Ind Pk) mode and 200 kHz frequency on the receiver. When in close proximity to the transmitter in induction mode, there is a direct signal from the induction antenna in the transmitter to the receiver through the air. Induction Peak (Ind Pk) mode is a newly added locate mode for use in closer proximity to a transmitter in Induction mode (<60 ft , 20 m typ.). Special (single) Peak (Spl Pk) would give the highest sensitivity, but is affected by the air signal more than Induction Peak (Ind Pk) mode.

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