TDR Calibration: Turnaround Times, On-Site Services & How It Works
Tra-Cal Lab has provided ISO/IEC 17025 accredited, NIST-traceable TDR calibration for over 35 years — trusted by NASA, the U.S. military, and NIST. We service every major brand, from Tektronix cable testers to Riser Bond fault locators, with faster turnaround and lower cost than the OEM. We offer expedited services, on-site calibration and Mid-Atlantic pickup and delivery to keep your operation running. Every certificate includes as-found/as-left data, so your measurements stand up to any audit.
Key Summary
TDR calibration verifies distance-to-fault accuracy against NIST-traceable precision airlines and calibrated cable standards of known length and velocity factor, and confirms pulse amplitude and width, reflection-magnitude readout, and velocity-of-propagation settings across the instrument’s ranges, with results documented on a calibration certificate. Standard turnaround is 3-5 business days with overnight rush available, and most TDRs should be calibrated every 12 months by an ISO/IEC 17025 accredited lab.
Why Choose Tra-Cal?
ISO/IEC 17025 Accredited
Our lab is independently audited every year by ANAB to the industry's most rigorous quality standard, so every calibration is audit-proof.
Overnight Rush Available
When downtime isn't an option, expedited service gets your instrument calibrated and back in your hands overnight or within three days.
NIST-Traceable
Every measurement we make traces directly back to national standards, giving your results documented accuracy you can defend.
Trusted by NASA, the U.S. Military, and NIST
The organizations with the most demanding measurement requirements in the country choose Tra-Cal — yours can too.
| Service | Turnaround |
|---|---|
| On-site Calibration Service | Same-Day |
| Standard calibration with certificate | 3-5 business days |
| ISO/IEC 17025 accredited calibration | 4-6 business days |
| Expedited / rush | Overnight to 3 days |
TDR Calibration Turnaround
TDR Brands & Models We Calibrate
| Manufacturer | Popular Models We Calibrate |
|---|---|
| Tektronix | 1502B, 1502C, 1503B |
| Riser Bond | 1205C, 1270A |
We support over 100 test equipment manufacturers — contact us and we’ll confirm coverage for your exact instrument.
Don’t see your model?
Equipment & Standards Required
We maintain the following equipment and conditions required to calibrate a TDR accurately:
NIST-traceable precision airlines and characterised cable standards of known electrical length with at least a 4:1 test accuracy ratio
Calibrated oscilloscope or sampling head for verifying pulse amplitude, rise time, and width
Precision terminations, opens, shorts, and mismatch standards for reflection-magnitude checks
Manufacturer’s calibration procedure and published distance and amplitude accuracy specifications
Stable environment: 23 °C ± 5 °C, controlled humidity, and NIST-traceable reference standards with a documentation system
How to Calibrate a TDR: Step-by-Step
Step 1: Inspect connectors and allow the instrument to warm up. Gauge and inspect the test-port connector, check the battery and display, and let the instrument and reference standards stabilize at 23 °C ± 5 °C for the manufacturer-specified warm-up period.
Step 2: Perform “as found” verification. Record distance-to-fault readings against each reference standard, on every range, before any adjustment. As-found data proves whether previously located cable faults were dug or spliced at the right point.
Step 3: Verify distance accuracy, pulse characteristics, and reflection readout. Measure known airlines and cable standards across the ranges with the velocity of propagation set correctly, confirm the pulse amplitude and width against a calibrated scope, and check reflection magnitude against open, short, and mismatch standards.
Step 4: Adjust, repair, or reject as required. Apply the manufacturer’s timebase and amplitude corrections where the design allows, replace worn test-port connectors, and service the pulse generator or sampler as needed. Instruments outside specification after service are documented and returned as limited-use or rejected.
Step 5: Perform “as left” verification and issue documentation. Re-run the full range set after any adjustment and issue an ISO/IEC 17025 accredited certificate with as-found and as-left data, measurement uncertainties, and NIST traceability.
Pro tip from our lab: Always request as-found/as-left data on your certificate. Without it, you can’t assess whether measurements taken before calibration were reliable — a common audit finding.
How Often Should You Calibrate a TDR?
| Usage Profile | Recommended Interval | Notes |
|---|---|---|
| Daily industrial / field use | 6–12 months | Shorten after drift or overload events |
| General lab / bench use | 12 months | Industry-standard default |
| Regulated environments (ISO 9001, FDA, A2LA audits) | Per quality system, typically 12 months | Interval must be documented and justified |
ISO/IEC 17025 does not specify fixed calibration intervals. It requires that intervals be reviewed and adjusted as necessary to maintain confidence in the equipment. Recommended intervals are typically 6–12 months, adjusted based on documented risk assessment and historical stability data per the lab’s calibration program. A2LA and ANAB are accreditation bodies — distinct from quality-system frameworks such as ISO 9001 or FDA requirements.
Frequently Asked TDR Questions
Q: How much does TDR calibration cost?
A: TDR calibration cost depends on the number of distance ranges verified, whether both metallic and optical modes are present, the connector interfaces involved, and whether accredited (17025) certification is needed, and whether accredited (17025) certification is required. Contact Tra-Cal for a quote.
Q: Can I calibrate a TDR myself?
A: You can perform verification checks against a known reference, but formal calibration requires traceable standards with a 4:1 accuracy ratio and documented uncertainty.
Q: What is the difference between calibration and adjustment?
A: Calibration is the documented comparison against a standard; adjustment is the correction made when readings fall outside tolerance.
Q: How long does calibration take?
A: Standard turnaround is typically 3-5 business days; Tra-Cal offers expedited service options.