Tilted Sondes, Measuring Depth Sonde Mode

NaviTrack® II

Figure 23 – Sonde Locate: Equator

•Double-check the two Pole locations.

•Notice that the Measured Depth reading at the maxi- mum Signal Strength location is reasonable and con- sistent. If it seems far too deep or too shallow, recheck that there is an actual maximum Signal Strength at that location.

•Notice that the poles and the point of highest Signal Strength lie on a straight line.

IMPORTANT! Remember that being on the Equator does not mean one is over the Sonde. Seeing two Poles aligned on the dis- play is not a substitute for centering over each Pole separately and mark- ing their locations as described above.

If the Poles are not visible, extend the search.

For best accuracy use the bubble level. The mast MUST be vertical when marking the Poles and Equator, or their locations will be less accurate!

It doesn’t matter whether you locate the Poles first, and then the Equator, or the Equator first, and then the Poles, or one Pole, then the Equator, and then the other Pole. You can even locate the Sonde using just the Signal Strength, and then verify your result with the Poles and Equator. What is important is that you verify all the data points, and mark the Sonde’s position where the signal is highest.

Tilted Sondes

If the Sonde is tilted, one Pole will move closer to the Sonde and the other farther away so that the Sonde lo- cation no longer lies midway between the two Poles. The Signal Strength of the nearer Pole becomes much higher than that of the more distant Pole if the Sonde is vertical (as it could be if it fell into a break in the line); however, it can still be located.

If the Sonde is vertical what is seen on the screen is a single Pole at the point of maximum Signal Strength. (The RIDGID Floating Sonde is designed to have a

single Pole “visible” and is weighted to maintain the Sonde on a vertical axis. See Note below.)

It is important to realize that a severely tilted Sonde can cause the Pole locations and the Equator to appear offset because of the angle of the Sonde; but maximiz- ing the Signal Strength will still guide to the best location for the Sonde.

Floating Sondes

Some Sondes are designed to be flushed or to drift down a pipe pushed by water flow. Because these Sondes swing much more freely than a torpedo-shaped Sonde in a pipe, they can be oriented any which way. This means the Equator may be distorted by tilting, and the location of the Poles may vary. The only guarantee of having located a floating Sonde is maximizing the Signal Strength and double-checking that the signal falls away on every side of the maximum signal location.

NOTE! If a Sonde is moving, it may be easier to “chase” a pole and then pinpoint the actual position of the Sonde after the Sonde has stopped moving.

Measuring Depth (Sonde Mode)

The NaviTrack II calculates Measured Depth by com- paring the strength of the signal at the lower antenna to the upper antenna. Measured Depth is approximate; it will usually reflect the physical depth when the mast is held vertical and the bottom antenna is touching the ground di- rectly above the signal source, assuming no distortion is present.

1.To measure depth, place the locator on the ground, directly above the Sonde.

2.Measured Depth will be shown in the lower left hand corner of the NaviTrack II’s display screen.

3.A Measured Depth reading can be forced by pressing the Select Key during a locate.

4.Measured Depth will be accurate only if the signal is undistorted.

Clipping (Sonde Mode)

Occasionally the Signal Strength will be strong enough that the receiver will be unable to process the entire sig- nal, a condition known as “clipping”. When this occurs a

warning symbol will appear on the screen. It means that the signal is particularly strong.

NOTE! Measured Depth Display is disabled under clipping conditions.

14	Ridge Tool Company