About Pipes & Cables - SubSurface Instruments AML Operator's Manual

• The "AML" MAY detect the edge–middle–edge of a shallow pipe, or a large pipe, as you "slice" through the
cross-section. If it is a non-metallic pipe with a tracer wire, you may detect the edge-middle-edge-wire or
wire-edge-middle-edge... depending on which side of the pipe the wire is on, in the trench; unless the wire is
in direct line with the edge or middle of the pipe. ...as show below:
If Searching Vertically as in Pinpointing:
Pipe & Cable cross section on the right
shown "oblong" on purpose. The unit will
detect the "edges" it "sees" in a direct line
from/to the unit. If the pipe at the right
were perfectly round, the hits may be
exactly the same distance from the side
as they were from the top. Notice also
that the cable is in the path of the bottom
edge of the pipe, so only three "hits"
would be seen in the case from the right.
While we've found the "scan & step" method to be the quickest in most cases; if the pipe is large enough, one may be able to trace
slowly along the pipe similar to the method of using an "RF" locator, if one moves slowly, and keeps the unit steadily "on" the pipe
while holding the unit in the vertical position only... do NOT swing back and forth like an "RF" locator. In such a case, one would
detect only the "center hit", unless the pipe is very large. One reason we don't use the walk-in-line method is it is hard not to detect
your feet or shoes when walking and holding the unit vertical.
You MAY be able to "test" the AML on pipes & cables lying on top of the ground or in an open trench so that you can see exactly
how it locates... Keep in mind that it "loves" edges: that is, the sides and top of a round pipe, again depending on size... thus a
small cable or pipe, or a deep one, would only produce one "hit", on the rounded side that is directly in line with the unit.
About Pipes & Cables
"hit" "hit" "hit" "hit"
Pipe
w/Cable
End View
NOTE: It may not always be possible to detect the
target at 45-degrees due to distance caused by depth.
If Searching at an angle:
"hit"
"hit"
"hit"
<Cable
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