3M 2273M-iD 用户手册

 26 

78-8130-6150-0 Rev G

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.

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.