Locating in the horizontal directional drilling (HDD) industry was initially based on locating a buried cable by sweeping the locator back and forth to find the highest signal strength (peak signal), indicating that the locator was over the cable. Unfortunately, this method did not always guarantee an accurate location of the cable, nor did it provide any depth information.

This “peak signal” method was adapted to HDD with the introduction of a transmitter that provides information on the position and depth of the drill head. However, this method is unreliable and inaccurate because the peak signal strength is not always directly above the transmitter housing.

In addition, peak signal locating doesn’t show where the drill tool is headed. Think of drilling like driving a car: it is more effective to look ahead through the windshield to see where you are going than to look down at the road through the floorboard to keep the car (drill tool) on the road (drill path).

DCI’s design uses a “locate point” in the transmitter signal. The Front Locate Point (FLP), which is out ahead of the transmitter, shows where the transmitter housing is heading.

DCI invented the Ball-in-the-Box user interface to make it quick and intuitive to find a locate point, speeding up drilling jobs: just move the locator so the ball moves into the box on the screen.

Finding a locate point also helps you find the drill head itself.

There is a second locate point behind the transmitter called the Rear Locate Point (RLP). The two locate points, combined with a Locate Line (LL), pinpoint the precise location of the transmitter housing below ground.

They are arranged like an airplane, where the Front Locate Point is the plane’s nose, the Rear Locate Point is the tail, and the Locate Line is the wings.
 

If your drill path requires a consistent depth or to maintain a constant pitch, use the predicted depth feature at the Front Locate Point. This eliminates the need for depth readings over the transmitter, speeding up the drilling process.
 

Interference can cause incorrect locate data that reduces locating accuracy. There are two different types of interference that can distort the transmitter signal: active and passive.

Active interference, or “noise”, consists of anything that emits a signal that interferes with the transmitter signal. Example sources include power lines, radio towers, cathodic protection, fiber tracer lines, invisible dog fences, security systems, and traffic signal loops. Falcon’s frequency optimizer finds the best frequencies to avoid noise.

Passive interference consists of anything that blocks or distorts the transmitter signal resulting in incorrect depths or missing data. Example sources include rebar, guard rails, bridge abutments, chain link fencing, salt/saltwater, and soil high in metal ore. The Falcon sub-kHz transmitter (available for Falcon F5 and F5+ only) helps cut through passive interference without distorting the signal.

An A on the screen can indicate signal Attenuation due to the presence of excessive interference, which can make depth readings inaccurate. Attenuation is normal in shallow depths less than 8 feet (2.4 m). If the signal strength is also flashing, this indicates extreme interference. Depth and locate points may be compromised and the locator will not calibrate.

Noise varies by amount and frequency depending on where you are and even the time of day. That’s why it’s important to find the best frequencies for every bore.

This is called frequency optimization, and only Falcon has it. Using frequencies with the highest probability of success against noise increases locating accuracy and reduces the risk of tripping out.

Falcon’s frequency optimizer scans through hundreds of frequencies, then bundles those with the lowest noise into finely-tuned bands that work best for the current job.

Select two bands and switch between them mid-bore if needed (not available on the Falcon F1 with singleband).

The Falcon Plus locators with Quick Scan Pair offer features to make the selection of bands faster and easier. Two clicks select the two preset bands selected for your region.

Use the trigger switch under the handle of your Falcon F1/F2 to navigate the menu system and select options.

Click to open the Main menu and move between options.

Hold briefly and release to make a selection.

Hold while over the Locate Line (LL) for a depth reading.

Do nothing in a menu for five seconds to return to the Locate Mode screen.

The Locate Mode, Depth, and Predicted Depth screens are the primary screens you will use for locating.

When the locator is detecting a signal from a transmitter, the Locate Mode screen provides real-time data about the transmitter’s location, temperature, pitch, roll, and signal strength.

Depth data appears when the trigger is held at the Locate Line (LL) and predicted depth appears when held at the Front Locate Point.

1. Locating ball (FLP or RLP)
2. Locator
3. Roll indicator
4. Roll value
5. Roll/pitch update meter
6. Transmitter pitch
7. Power Mode (not available in legacy F1/F2) and Transmitter signal strength
8. Transmitter temperature

The Depth screen displays when the trigger is held with the locator at the Locate Line (LL).

1. Locate point (front or rear)
2. Bird's-eye view
3. Locate Line (LL)
4. Height-Above-Ground (HAG) setting on
5. Ground level
6. Transmitter depth
7. Transmitter battery strength

The Predicted Depth screen displays when the trigger is held with the locator at the Front Locate Point (FLP).

1. Ball-in-the-Box at FLP
2. Reference Lock indicator *
3. Transmitter battery strength
4. Horizontal distance between transmitter and FLP
5. Predicted depth * of transmitter

The predicted depth is the depth the transmitter is calculated to be at when it reaches the FLP if it continues on its current path.

In this example, if the drill head travels an additional 6'0" (1.82 m) at -0.2% pitch, it will be directly below the locator at 8'7" (2.62 m).

When a transmitter is level (zero pitch) underground:

• the locate points (FLP and RLP) are at equal distances from the transmitter
• depth displayed on the locator is the actual depth, and
• the Locate Line (LL) indicates a position above the transmitter.

1. RLP
2. LL
3. FLP

When the transmitter is pitched up or down, the transmitter signal field also tilts.

When the transmitter is pitched down (negative pitch), the locate line on the screen reflects a future position of the transmitter, assuming the transmitter stays on the same trajectory (projected depth).

When the transmitter is pitched up (positive pitch, shown below), the locate line on the screen reflects a position behind the transmitter.

The depth reading on the locator is based on the projected depth point, which is not the same as the actual depth of the transmitter.

1. RLP
2. FLP
3. LL
4. Fore/aft offset
5. Projected depth
6. Transmitter at positive pitch
7. 30% (17°)

The differences in position and depth between the projected depth point and the actual location of the transmitter can be relatively small at low pitch and/or shallow depth.

When drilling at a steep pitch and/or significant depth, the differences are greater.

For example, if the transmitter is at a plus or minus 30% pitch and a 33'1" (10.1 m) depth, the locator depth reading will be 35' (10.7 m) (just under 6% difference from actual depth) and the locate line will be 6'6" (2 m) from being directly above the transmitter (-30% places the LL ahead and +30% places the LL behind).

You can use the pitch and the projected depth reading on your locator to determine the actual depth and the position (fore/aft) of the locate line:

Actual Depth

Fore/Aft Offset

For a given pitch, you can calculate actual or projected depth:

This calibration procedure is rarely needed. If you find it necessary to calibrate with the transmitter in the ground, contact DCI customer service for information on this option, and perform the procedure with caution.

DigiTrak transmitters (Tx), with the exception of DucTrak, have temperature overheat indicators (temp dot) on the front end cap.

1. Black temp dot (voids warranty)
2. Normal white temp dot

The temp dot has an outer yellow ring with a temperature-sensitive 1/8" white dot in the center. If the center temp dot is black, the transmitter has been exposed to excessive heat and should no longer be used.

Depth Increase in Inches (cm)

Slopes between 50% and 100% are provided for reference only and do not represent typical drilling conditions. All numbers are based on math only and do not take into account extremely soft or extremely hard soil conditions, which may cause depth values to vary.

Depth Increase in Inches (cm)

Slopes between 50% and 100% are provided for reference only and do not represent typical drilling conditions. All numbers are based on math only and do not take into account extremely soft or extremely hard soil conditions, which may cause depth values to vary.