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Quick answer
Sonic tracers can automate grade control under string lines for curb preparation, reducing labor and improving consistency. However, their effectiveness depends heavily on string material, peg spacing, and machine integration. In many regions, manual checking with levels and tape remains dominant due to cost and simplicity.
Sonic tracer technology and grading systems
A sonic tracer is a non-contact sensor that reads the position of a reference line—typically a string—and adjusts the grading blade accordingly. It’s often integrated into systems like Topcon System 5 or similar machine control platforms. These systems use:
String line material and sensor compatibility
The success of sonic tracing depends on the physical properties of the string:
Field experience and practical adaptations
One grader operator in Queensland used a Topcon-equipped CAT 12H with a sonic tracer. He found that switching off auto mode near pegs was essential to prevent erratic blade movement. He also noted that using wire-traced string improved sensor reliability.
Another operator in Canada preferred manual checking. He placed material according to stakes, compacted it, then had a laborer walk behind the blade with a level and tape, checking every 5–6 feet. Adjustments were made on the fly, and the crew completed 900 meters of curb prep in under three hours.
Labor cost and regional variation
In Australia, employing a skilled grade checker can cost $60–$70 AUD per hour when factoring in wages, superannuation, insurance, and payroll tax. This drives interest in automation. In contrast, Canadian labor rates for similar roles may be as low as $11–$20 CAD per hour, making manual methods more viable.
Recommended practices for sonic tracer use
Conclusion
Sonic tracers offer a promising way to reduce labor and improve grading precision under string lines, especially in high-cost labor markets. Their success depends on string material, peg layout, and operator skill. While not universally adopted, they represent a step toward smarter curb preparation—particularly when paired with robust machine control systems and thoughtful field adaptation.
Sonic tracers can automate grade control under string lines for curb preparation, reducing labor and improving consistency. However, their effectiveness depends heavily on string material, peg spacing, and machine integration. In many regions, manual checking with levels and tape remains dominant due to cost and simplicity.
Sonic tracer technology and grading systems
A sonic tracer is a non-contact sensor that reads the position of a reference line—typically a string—and adjusts the grading blade accordingly. It’s often integrated into systems like Topcon System 5 or similar machine control platforms. These systems use:
- Sonic sensors mounted on the moldboard or mast
- Controllers that interpret string position and adjust blade height
- Manual override switches for peg interference
- Optional wire-traced string lines for improved signal clarity
String line material and sensor compatibility
The success of sonic tracing depends on the physical properties of the string:
- Thick bailing twine or wire-traced string: Offers better reflectivity and signal consistency
- Fishing line or thin nylon: Difficult for sensors to detect, especially in bright sunlight or dusty conditions
Field experience and practical adaptations
One grader operator in Queensland used a Topcon-equipped CAT 12H with a sonic tracer. He found that switching off auto mode near pegs was essential to prevent erratic blade movement. He also noted that using wire-traced string improved sensor reliability.
Another operator in Canada preferred manual checking. He placed material according to stakes, compacted it, then had a laborer walk behind the blade with a level and tape, checking every 5–6 feet. Adjustments were made on the fly, and the crew completed 900 meters of curb prep in under three hours.
Labor cost and regional variation
In Australia, employing a skilled grade checker can cost $60–$70 AUD per hour when factoring in wages, superannuation, insurance, and payroll tax. This drives interest in automation. In contrast, Canadian labor rates for similar roles may be as low as $11–$20 CAD per hour, making manual methods more viable.
Recommended practices for sonic tracer use
- Use wire-traced string lines for consistent detection
- Train operators to override auto mode near pegs
- Maintain clean sensor surfaces and calibrate regularly
- Combine sonic tracing with visual checks for critical grades
- Consider hybrid setups with whisker sensors or mechanical feelers
Conclusion
Sonic tracers offer a promising way to reduce labor and improve grading precision under string lines, especially in high-cost labor markets. Their success depends on string material, peg layout, and operator skill. While not universally adopted, they represent a step toward smarter curb preparation—particularly when paired with robust machine control systems and thoughtful field adaptation.
