Overview
IEC 61196-1-113:2018 specifies a standardized test method for determining the attenuation constant of coaxial communication cables used in communications and RF systems. Applicable preferably at frequencies ≥ 5 MHz, the standard defines equipment, calibration, measurement procedures, result expression and correction methods. This second edition (2018) updates the technical content of the 2009 edition and provides diverse form fitting equations to address ripple and noise in measured attenuation curves.
Key Topics
- Scope and applicability: Test method for coaxial cables used in communications; lower frequencies are permitted when the complex characteristic impedance magnitude approximates the nominal impedance or when a form fitting is applied.
- Equipment: Vector Network Analyser (VNA) for S21, scalar network analyser, or separate signal generator and receiver. Use impedance-matching adapters to limit reflection loss errors (matching tolerance indicated in the standard).
- Specimen preparation: Physical length must be determined with ≤1% uncertainty. A round-trip loss of ~40 dB across the test band is recommended to avoid multiple reflections, or apply form fitting if not achievable.
- Calibration and measurement: Calibration data for the test setup (including adapters and connectors) must be recorded and used to correct measured attenuation. The cable under test should stabilize at ambient temperature for a minimum of 4 hours; record ambient temperature.
- Result expression and temperature correction: Attenuation constant is reported in dB/100 m and calculated from measured and calibration attenuations divided by specimen length. When required, correct to a reference temperature (20 °C) using a correction factor K defined in the relevant cable specification (example: for copper coax with non-polar insulation K = 0.2 %/°C).
- Form fitting: To smooth ripples from impedance mismatch or measurement noise, a least-squares form fitting (polynomial/physics-based terms) is applied to corrected attenuation values. The edition adds diverse form fitting equations and prescribes least-square coefficient calculations.
Applications
- Verification of coaxial cable loss characteristics for RF links, broadcast, telecom and test lab qualification.
- Supporting cable specification compliance and procurement acceptance testing.
- Providing corrected attenuation data for system design, link-budget calculations and component matching.
Related Standards
- IEC 61196-1 (generic) – definitions and general requirements for coaxial communication cables.
- IEC 61196-1-108 – test methods for characteristic impedance, phase/group delay and propagation velocity.
- IEC TR 62152 – guidance on impedance matching and transmission properties of cascaded two-ports.
Following IEC 61196-1-113:2018 ensures repeatable, comparable attenuation measurements across laboratories and supports reliable RF and communications system performance analyses by addressing calibration, impedance matching, temperature correction and form fitting of measured attenuation curves.
Open preview (PDF)Coaxial communication cables - Part 1-113: Electrical test methods - Test for attenuation constant
