|  |

| |

Enabling better global research outcomes in soil, plant & environmental monitoring.

HandiTRase – TDR Measurement of Soil Moisture

Instruments for the measurement of moisture and dielectric properties
using Time Domain Reflectometry


Trase system, portable for use in the field





Every day, universities, colleges, government agencies, and commercial agriculture around the world rely on Trase System 1.

It all began over 50 years ago when Soilmoisture Equipment Corp. founder, P.E. Skaling, joined the staff of the U.S. Salinity Laboratory in Riverside, California. While there, he participated in soils/moisture research, and built the first Pressure Membrane Extractor and Tensiometers.

The Pressure Membrane Extractor, and subsequent ceramic plate extractors, first commercially available from Soilmoisture, made it possible to characterize the moisture-holding capacities of soils. Soilmoisture’s revolutionary tools radically transformed irrigation practices, allowing for the establishment of soil-moisture standards now used worldwide.

Soilmoisture continues the tradition of being the first to develop new technologies. One such technology is Time Domain Reflectometry (TDR), a process that measures the dielectric constant of materials and resultant moisture content. SEC began their work on this new technology in 1984, and since then SEC have developed the world’s most complete TDR instrument system: Trase.

back to top



A Trase in your future

Trase integrates strongly with your PC.Trase is not just a single instrument for measuring and monitoring moisture and dielectric constants using TDR; but is a growing, modular system made up of hardware, software, and firmware elements, arranged to provide a complete solution. It also means we can offer a wide selection of “off the shelf” alternatives packaged to meet your unique requirements.

Whether it’s a single manual field measurement or the sophisticated processing of arrays from remote sites, only one self-contained instrument – Trase – satisfies the diverse needs of commercial agriculture, research scientists, engineers, and government regulators.

Trase’s advanced application of TDR to moisture and dielectric measurement makes it the ideal multipurpose tool for a huge variety of professions and situations. These include:

  • Agricultural
    • Soils and Agronomy
    • Row & Tree Crops
    • Forestry
    • Plant Physiology
    • Horticulture
  • Environmental
    • Watershed Management
    • Stream Heights/Percolation Effects
    • Snowpack Evaluation
    • Landfill Monitoring
    • Restoration and Capping Integrity
    • Ground Truthing for Satellite Data
    • Environmental Monitoring
  • Industrial
    • Raw Materials Processing
    • Cement Deterioration
    • Landmass Saturation Stability
    • Verify Regulatory Conformance Standards
  • Geoscience
    • Hydrogeology
    • Rock Mass Stability
    • Solution Mining/Extraction Processes
  • Materials Research
    • Compaction
    • Unusual States: Gels, Slurries, and Suspensions
    • Water/Liquid Retention
    • Liquid and Solids Interface Levels


back to top



Trase satisfies your requirements by being:

Monitor remote field sites from your office.

The world’s most versatile TDR instrument

Trase is the only self-contained TDR instrument capable of investigating and monitoring not only soils, but a wide variety of other materials as well. It is fully field portable, and when you need to leave it at a remote site for several days or weeks, it can be accessed from home or office.

On site, Trase quickly measures the dielectric and subsequent moisture properties of soil, seeds, or other materials at a specific location, or, with the optional Trase Multiplexer, at up to 256 locations. Trase automatically logs your sensors at intervals ranging from once a minute to once a day. Using diverse waveguide configurations and associated conversion tables, Trase rapidly measures new or unusual materials. (Soilmoisture can supply these nonstandard TDR tools or you can develop your own.) Your ability to make a measurement using Trase is limited only by your imagination and creativity.



Designed and built to meet tomorrow’s needs

Trase is future-proof. It’s the only TDR instrument constructed with an open system architecture. There are five (5) STD bus expansion slots and you can choose from plug-in options like the 4 megabyte add-on Memory Board, the Multiplexer Control Board, or any of the other boards and equipment listed in the Trase Accessories Brochure. And because SEC is serious about meeting your future needs, SEC is continuously developing new options and capabilities for Trase hardware, firmware, and software.

back to top

Able to access extensive details – fast!

Examine your data immediately with the built-in screen.

Trase gives you the most complete, detailed information possible about your TDR measurement. More than just a number on a screen, it provides a complete measurement log conformable to “formality of operation” practices. Three primary screen functions (Measure, Data, and Graph) provide immediate ease of operation.

The Data Screen function for instance (see illustration), provides access to over 4,000 graphs or waveforms or 120,000 readings in a typical system configured with the optional 4 megabyte Memory Board. All memory allocations are user configurable into four dynamic storage areas. Help for all functions is as close as the on-line help button. You can work quickly and with confidence, knowing the detailed information you require is there and available when you need it.

Arrow symbol used in illustration.  indicates a scrollable field.

The professional solution that saves you time and money

A Trase system provides a cost-effective, timely, and complete solution to your most pressing moisture or dielectric measurement requirements.

Partial, “homemade” TDR measurement solutions, fabricated from cable testers, computers, and independent software simply cannot match Trase’s robustness, user-friendly features, or potential for enhancement. Other TDR systems may appear less expensive, but beware of false economies. Limited capabilities and higher hidden costs in sensors, waveguides, or multiplexing can turn a bargain into a burden.

“Do-it-yourself” or “limited” TDR systems are rarely economical alternatives; both have long term additional costs. You either end up paying for continuing incompatibility between subsystems or you incur large improvement and/or repurchase expenses.

Only Trase is designed to provide a wealth of “off the shelf”, cost-effective solutions, year after year, in one professionally integrated package. When it comes to making a TDR purchasing decision, give your agency, institution, or company the best long-term return on investment and insist on a Trase system.

back to top



How does Trase measure moisture content?

Illustration of pulse travel through the waveguides.

Trase measures pulse speed and the dielectric constants

Every material has a “dielectric constant”; its ability to delay an electromagnetic field travelling through it. The typical range for these constants is from 1-80, with air = 1, a minimum delay, and water = 80, a maximum delay. “Dielectric constants (K)” are derived for specific materials, while “apparent dielectric constants (Ka)” are derived for a mixture of materials. Typical dielectric constants are Air K = 1, Minerals K = 3-5, and Water K = 80. In a complex mixture like soil, the apparent dielectric value will have a wide range. For example, dry soil, Ka = 3-6, has a high volumetric content of air and minerals, but little water. On the other hand, mud, Ka = 40-50, has a large volume of water and minerals, but very little air. In all types of materials where one component has a substantially higher dielectric constant compared to the other components, the apparent dielectric constant measured in conjunction with a conversion table, can give the volumetric content of the component which has the higher constant. Thus, the volumetric content of water in soils, cements, plant materials, grains, etc. is readily determined by measuring their apparent dielectric constant.

Trase uses picosecond resolution

In Time Domain Reflectometry (TDR), the elapsed time of an electromagnetic pulse travelling along a waveguide of known length is measured, and average pulse speed and subsequent dielectric constant determined. Trase instrumentation uses picosecond (1 picosecond = 10 -12 second = 1/1,000,000,000,000 second) timing resolution to make measurements. Travel time is measured from the start of the waveguides to the end points. Trase uses a manual “zeroing” or a patent pending “Timing Mark” to establish a waveguide start. It then finds waveguide ends by detection of the “end reflection”, a characteristically abrupt change in voltage and impedance values as the electromagnetic pulse reaches the ends of the waveguides.

In operation, Trase launches a series of powerful fast rise step pulses down the cable (see above illustration) into the waveguide. Voltage samples are taken along the waveguide at precise 10, 20, or 40 picosecond intervals. It takes several nanoseconds (1/1,000,000,000 second) for the pulse to complete the journey down a 20 cm long waveguide and through the surrounding material. A “TDR waveform” for the material is produced by combining over 1,000 averaged sample points, displayed in a 10, 20, or 40 nanosecond long “sampling window”. It is the number of sample point intervals from waveguide start to end point (end reflection) that will determine lapse time, average pulse speed, and the dielectric constant. In Trase, conversion tables are used to convert the derived dielectric constant into the volumetric amount of a component within a mixture, such as the volumetric percent of water in soil.

Trase’s powerful graphic waveforms

The power of TDR is in the waveforms; the ability to read and directly compute pulse travel times using the horizontal time base axis (x). Another power of TDR is in the nuances of physical states, bulk electrical conductivity, structures, dispersion, mixing and settling of materials that can be discerned by the investigation of the vertical impedance axis (y). Higher impedances can indicate air pockets, freezing fronts, oil on water, etc., while lower impedance levels may indicate water intrusion, a compaction region, or a saline zone. Trase was designed and built to provide you with the best tool to investigate and quickly apply the power of TDR technology.

TDR can indicate air pockets and water intrusion. Vertical impedance axis graphs for different soils and materials. Conversion tables are available for a wide range of materials.

back to top



Trase in the field.

Trase – the leader in TDR technology by:

Colour scheme for icons - comparing Trase to other systems.

Using advanced pulse and low loss switch technology

High speed pulse and low loss switching.

Trase is one of very few TDR instruments incorporating advanced high speed hybrid step pulsers. And it is the only TDR pulser with a whopping 1.5 volt rise time in less than 200 picoseconds. This vital extra power allows you the greatest penetration into media surrounding the waveguides and permits the longest extended cable runs for multiplexing options. Trase Multiplexer users also benefit from ultra low loss PIN diode switching, resulting in clean clear pulse returns. No other TDR equipment can match the power or effective switching capabilities of Trase.

Sampling at more points for better resolution

Trase features a high precision 12-bit A/D converter with over 1,000 sampling points.

Trase and metallic cable testers are the only TDR equipment that provide step pulse capabilities and the ability to display complete TDR waveforms. With a cable tester, the measurement is recorded with a low resolution 8-bit A/D (256 steps) converter having no more than 250 sampling points. Trase, on the other hand, uses a high precision 12-bit A/D converter (4,096 steps) with over 1,000 sampling points. You can be missing a great amount of detail and nuance in measurements using older, low resolution equipment.

Using conversion tables that fit real world conditions

Full range conversion table for soil.

Trase uses a standard conversion table to convert Ka values for soils into volumetric water percent, in the total range of 0-100% of water; a great advantage over instruments using the limited Topp formula (which has a useful range to only 45% moisture content). Instruments programmed in this manner, or those with limited mathematical input functions for determination of moisture content, provide only reasonable approximations and cannot easily be adjusted to the many irregularities in real world dielectric relationships. Only the full range conversion table employed in Trase provides the precision necessary to follow nature’s often inconsistent and irregular patterns of dielectric relationships. A fact that is especially important if your work involves studying a setting gel, a settling slurry, or a crystallising liquid.

Using multiple conversion tables

Multiple special conversion tables can be downloaded.

Trase not only more closely reflects real world relationships with accurate conversion tables, but is also capable of accessing special conversion tables “on line”. Because multiple special conversion tables can be downloaded to Trase, users have tremendously extended opportunities for the measurement of soils and many other materials. With Soilmoisture’s WinTrase software and additional firmware, sensor sets in an array can be allocated specific conversion tables for differing materials. This unique capability allows Trase to remotely monitor multiple processes of associated materials in a single multiplexed array system.

Finding significant information in a TDR waveform

Trase waveforms give valuable data about impedance over time.

Important information about the media being measured is obtained from the full TDR waveform graphs that show impedance changes over time. Such detail cannot be obtained with return waveforms from impulse TDRs or from shorted waveguides. Impedance features such as electrical conductivity changes, compaction zones, interface conditions, and distribution effects (to name only a few) simply are not visible.

Trase is designed for very powerful, unrestricted step pulse operations to produce optimal waveforms which can be used to measure and monitor as many dielectric/impedance aspects of a material as possible. Only Trase gives you the power to make maximum use of TDR technology.

back to top



Rugged construction, easy to use

Trase disassembled to show interior parts.The detachable top cover storage area houses the Trase Waveguide Connector and 15 cm Waveguide Set. A sealed access port allows connection to a variety of external electronic devices.

Open system architecture for future enhancements provides eight slot STD bus card cage construction letting you upgrade your system in minutes.

Rugged aluminium case protects Trase’s internal components. A modular approach combining top and bottom portions with heavy-duty latches and mated molding provide a water-resistant seal when case is closed for transport or automatic data acquisition.

Easy-change battery packs provide a reliable, long-term portable power supply. The specialized capacitive battery packs connect easily via the 8-pin DIN connector for recharging the batteries (within a maximum of 12 hours – you can even charge the battery pack while Trase is operating from a standard outlet or mobile power source). An internal Cap-Battery provides a 20 minute power reserve to retain Trase memory during power pack changes.



Detail view of faceplate and controls.


Easy viewing, large, very high resolution 128 x 256 dot format, supertwisted contrast graphic LCD display with keypad-controlled backlighting.

Easy access to internal card cage circuitry with service handle.

Quick-connect to Trase TDR pulse power using standard BNC connector allows for easy hookup to shielded coaxial cable from Trase Multiplexer, TDR sensing devices and waveguides.

Easy to carry handle with molded grip.

RS-232-C serial port facilitates transfer of stored data to computer printer or terminal. Error correcting compressed format allows for extremely fast transfer for either on-site data gathering or by modem from remote access operations.

Multiplexer ready with a 15 pin d-subminiature connector port to provide access for multiplexing and sequence switching.

One-key control with a 28-key alphanumeric membrane switch keypad environmentally sealed faceplate against moisture, dirt, and other contaminants. Major instrument operations are controlled with single function key entry.

Carrying comfort provided with the strong carrying handle with molded grip. Friction control permits support adjustment for bench top use.

Power port allows battery charging and use of auxiliary power from a wide range of power inputs.

A Variety of Low Cost Waveguides are available to meet your needs. You can choose from our standard stainless steel waveguide rods for the Connector handle, the Buriable Waveguide Probes (both shown here), or you may opt for a number of new and innovative waveguides featured in our Trase Accessory Brochure.

Connector handle and rods.
Connector handle and rods.
Buriable waveguide and Connector handle.
Buriable waveguide and Connector
handle with rods fitted.
Buriable waveguides.
Buriable waveguides.

back to top



A set of standard screens for simple operation

Measure screen

Measure screen.To make a soil moisture measurement with the Measure Screen, you specify the waveguide type and length, the conversion table to be used, and press “Measure”. In seconds, the percent volumetric water content will be displayed. To retain the reading in memory, press “Save Reading”. You may also save both the reading and the graph of the TDR waveform by pressing “Save Graph”.




Data screen

Data screen.The Data Screen displays a database listing of currently stored readings and graphs for quick review. The search feature sorts through thousands of readings and hundreds of graphs to locate the reading you want displayed. Graphs and readings can be dynamically allocated to any one of four separate memory storage locations. You can also independently transfer readings and graphs to a separate printer or computer from the Data Screen.




Graph screen

Graph screen.The Graph Screen is a powerful, investigative tool. Trase automatically captures the waveform and displays it full screen for highest possible resolution. Over 1,000 points of data are represented on a horizontal scale of nanoseconds and a vertical scale denoted in millirho. Two handy time (t) markers, controlled at the keypad, allow for precise measurement of any two points on the TDR waveform.

These extremely informative step pulse TDR graphs provide insight into propagation velocity (speed of pulse travel), time delays, attenuation, and impedance differentials. The graphical data can easily be imported into standard spreadsheets such as Excel® and Lotus 1-2-3®.

Arrow symbol used in illustration. indicates a scrollable field.

back to top



A wealth of features and options in secondary screens

The Trase Operating System puts Trase’s many capabilities at your fingertips. The software is organized by tasks you will typically need. Separate “Application Screens” are accessed and driven via the 28-button, alphanumeric keypad. Cycling through the Applications Screens is simply a matter of pressing the “Shift” + “Next Screen” or “Shift” + “Past Screen” buttons.

The setup screen

4 secondary screens.The Setup Screen is used to define the units of measure, set the internal calendar and clock, designate and label the memory storage areas, define the protocols necessary for Trase to interface with computers and modems, and to accomplish data transfer and/or remote control.

The autolog screen

The Autolog Screen allows you to program the initiation of a series of unattended moisture readings or TDR measurements. To implement this feature you need only set the time interval between readings and the total number of readings to be taken. You have the option of either storing just the reading or saving the reading and its associated waveform graph. The Autolog Screen also provides a “Sequence Switch” which provides a momentary closure to signal or sequence ancillary equipment after a Trase Autolog measurement.

The TDR screen

The TDR Screen operates in conjunction with the Graph Screen and provides TDR measuring capabilities similar to that of a cable tester. Simply key in the start time and end time of the sampling period you wish to observe and press the “Measure” key. The Screen will automatically change to the Graph Screen and display a TDR waveform for the sample period requested.

This important display feature, in conjunction with special waveguides, can be used for TDR sampling and waveform interpretation of various materials. The TDR Screen is useful in checking continuity of transmission lines and finding breaks. This screen also functions in the measurement of dislocation and faulting effects using special cable sensors.

The multiplexer screen (optional)

This Trase screen appears only when the optional Trase Multiplexer Control Card is installed. Trase, when connected to the Multiplexer via the Mux Port, auto-configures itself to the Switching Boards in the Multiplexer enclosure. With the Multiplexer Screen you can see the configuration and verify that your setup is correct and fully operational. You can either manually select the channels to be measured or, through the Autolog Screen, program a series of measurements that can be taken automatically over an extended period of time. All measurements and waveforms taken can be stored in Trase memory for later use.

back to top



Add the Trase Multiplexer for array measurements

The strong, weather-tight Multiplexer enclosures are made of fiber-reinforced plastic, complete with mounting bracket for one or more 16-channel TDR Switching Boards. Both Multiplexer models work with Trase system equipment and are compatible with Tektronix Metallic Cable Tester systems. Large access holes in the case bottoms allow for connection to numerous TDR waveguides and sensors. Two easy interconnects to the BNC and Mux Ports are also provided. You can measure day or night, summer or winter, 24 hours a day, 365 days a year. With an accessory solar charger, batteries, and remote access configuration, the possibilities for TDR measurement are unlimited.

Photo of multiplexer with Trase.
Model 6020B17 offers 256 channels for automatic measurement of large TDR arrays. Its large enclosure (24 inch H x 29 inch W x 9.5 inch D) holds up to 17 Switching Boards.
Photo of multiplexer.
Model 6020B5, can hold 76 channels (5 Switching Boards) and is designed for measurement of smaller TDR arrays. This model consists of a smaller enclosure (24 inch H x 15 inch W x 9.5 inch D).

All Multiplexer Switching Boards are self-configuring. That means you can count on easy, hassle-free installations. Use only as many Switching Boards as necessary for your current project, and add additional boards later. There is no program to rewrite and no equipment to reconfigure and check … you just plug and go!

Instead of slower, signal-degrading relay switches, only PIN diode switches are incorporated in the Trase Switching Boards. PIN diodes are the same semiconductor technology that is used to switch sophisticated microwave signals. The Switching Boards attenuate less than 1 dB loss per switch, with a maximum of two switching levels and that keeps pulse strength to an absolute maximum.

Trase and the associated Multiplexer provide the greatest flexibility possible in any TDR measurement system because they are able to read and measure both “balanced” and “unbalanced” signals. Most TDR systems can only measure signals and waveforms from a waveguide with an included pulse transformer (that matches [balances] impedance levels) known as a “balun”. Other systems rely on a three-prong configuration coaxial waveguide to measure “unbalanced” waveforms. Trase (and only Trase) Multiplexers have been designed to handle and measure under both conditions.

Graph of moisture profile over multiple depths and time.

Typical moisture profile detail using Trase Multiplexer. Sensors were buried at multiple depths
from 6 cm to 120 cm. Measurements were made at 10 minute intervals, 24 hours a day.

back to top



Examples of Trase use

Trase installed in a cultivated field.

In Agriculture

Trase can be used to establish irrigation practices by defining water needs and monitoring water distribution and uptake. It has applications in all environments from row crops to tree farms. TDR finds many uses in the lab, as well as in places like greenhouses, nurseries, soil physics and hydrology labs, and anywhere else it is necessary to measure and monitor moisture change 24 hours a day.

Tractor cultivating.
Buriable Trase waveguides permanently installed in concrete.

In Construction

Trase provides construction specialists, concerned with the long term effects of water intrusion, cement deterioration, structural settling, and roadway heaving, with a new tool to both investigate and monitor these common conditions. TDR and Trase can also be used to monitor displacement of overburden in tunneled mining operations.

Pouring concrete in the construction industry.
Nuturing a tree seedling.

In the Environment

Trase delivers invaluable information about a watershed such as rain fall events, evaporation rate, and snow and stream levels. In addition, Trase has been used for years in the monitoring of liner and cap integrity at hazardous waste sites and in those locations where sludge and gray water application effects must be monitored.

Trase monitors moisture in a greenhouse.
Trase in heavy industry process control.

In Process Industries

Trase and TDR are finding acceptance as the method to monitor and control those processes associated with moisture content, compaction, and uniformity. In addition, Trase can be adapted for use in measuring liquid or powder interface levels, phase changes and suspension characteristics.

Trase monitoring and controlling moisture content.

Our experienced engineers and technical sales representatives are available to quickly meet your individual requirements with an extensive array of standard products and accessories. Cost-effective, specialized solutions tailored to meet your specific needs are also available. Both Multiplexer models can be adapted at the factory for specialized PC switching of TDR, or other high frequencies (above 500 MHz), carried on standard 50 ohm RG-58 coaxial cables with BNC terminations.

back to top



Trase general specifications


Measuring Range 0 to 100% Volumetric Moisture Content
Measuring Accuracy +/- 2% Full Scale or better with the Standard Waveguide Connector
Operating Temperature 0 to +45°C
Power Supply 2 each, sealed, gelled electrolyte batteries, supplied. Total capacity 7 amp hours. Recharge time: 12 hours. Auxiliary power input 18-24 volts AC or 12 volts DC, 2 amps, for battery recharge or independent operation.
Connecting Ports BNC Port – For waveguide connection
RS-232 Serial Port – for data transferal
Multiplex Port – 15 pin D-SUB, for use with Multiplex accessory equipment
Power Port – 8 pin DIN
Memory Standard 256 kb Memory with storage capacity for at least 200 graphs / 6,300 readings.
Optional 4 Mb memory board increases storage to a total of at least 3,900 graphs / 122,800 readings.
Automatic data tagging of reading time/date/reading number plus user-defined label.
Autologging capability with reading interval range from one per day to one per minute.
Electronic Specifications Measuring pulse, 1.5 volt, peak to peak rise time less than 200 picoseconds.
Sampling resolution 10 picoseconds.
Graphic display: 128 x 256 dot supertwist matrix, backlighted LCD.
Battery charge status indicator lights (3).
Circuit breaker protection.
Hardware: 8-slot card cage construction, 3 system boards, 5 optional slots.
Included Items Trase System
Waveguide Connector
Set of 15 cm long Waveguides
Buriable Waveguide
Battery Charger
Operating Instructions

Request More Information