Overview
IEC 62037-4:2012 (consolidated with Amendment 1, 2025) specifies recommended test fixtures and procedures for measuring passive intermodulation (PIM) generated by coaxial cables. Part of the IEC 62037 series on intermodulation level measurement, this standard defines two dynamic test methods (clamped cable loop and flexing tool) and one static test, and requires reporting of the maximum PIM level observed in each condition.
Key topics and technical requirements
- Test methods
- Dynamic - clamped cable loop: Bend cable into a "U", clamp limbs, apply lateral movement in three directions (d1, d2, d3). Minimum movement amplitude is 20 mm; perform at least 3 cycles per axis with cycle duration 1–5 s.
- Dynamic - flexing tool: Thread cable through a flexing fixture and translate the tool along the test length; rotate the fixture 90° to test the orthogonal plane.
- Static: Measure PIM with the cable at rest; for large-diameter feeder cables (≥16 mm nominal) use a short flexible jumper of known low IM if required.
- Test setup
- Use the IEC 62037-1 measurement method and IM test set.
- For long cables with one-way insertion loss ≥ 10 dB, use a reverse set-up and connectorize only the end under test.
- Use connectors and terminations with known low IM performance (soldered joints preferred).
- Fixtures and dimensions
- Clamps must avoid crushing or kinking; flexing tool dimensions and groove diameters are specified for different minimum bend radii (see tables in the standard).
- Reporting
- Record the maximum level of passive intermodulation in static and dynamic conditions (before, during, after movement).
Applications and who uses it
IEC 62037-4 is essential for:
- Coaxial cable manufacturers performing qualification and production testing for PIM performance.
- Independent test laboratories and QA teams verifying compliance for telecom and RF installations.
- Wireless network operators and system integrators assessing cable suitability for PIM-sensitive applications (e.g., cellular base stations, DAS).
- RF design and test engineers specifying cable assemblies for low-intermodulation systems.
Practical benefits include standardized procedures to detect movement- or stress-induced IM, validating cable designs (flexible, semi-flexible, feeder) and ensuring reliable in-field RF performance.
Related standards
- IEC 62037-1 - General requirements and measuring methods for passive r.f. and microwave intermodulation.
- IEC 62037-3 - Measurement of passive intermodulation in coaxial connectors.
Keywords: IEC 62037-4, passive intermodulation, PIM measurement, coaxial cables, dynamic test, static test, clamped cable loop, flexing tool, IM test set.
Open preview (PDF)Passive RF and microwave devices, intermodulation level measurement - Part 4: Measurement of passive intermodulation in coaxial cables
