Do step attenuators need periodic calibration, and how do I detect drift?

Yes, periodic calibration is needed. Contact oxidation and wear, connector wear, temperature and humidity cycling, and mechanical stress all move attenuation slowly over time. To detect drift, compare key settings against a reference attenuator or a calibrated instrument, check repeatability at the same setting, establish a 0 dB insertion-loss baseline and trend it, and watch VSWR. Set the interval from usage frequency, shorten it for heavy use, and do a field check at the target frequency and setting before a critical measurement.

Key points

• Compare key settings against a reference attenuator or calibrated instrument
• Repeatability at one setting catches mechanical wear before accuracy does
• Trend 0 dB insertion loss as a baseline; a slow rise usually means connector or contact degradation
• VSWR drift points at connector wear rather than the resistive pads
• Shorten the interval for high-cycle use; do a pre-test field check at the working frequency

Products this applies to

KT3.0-90/1S-2S/5W

Push-Button Step Attenuator, 0–90 dB, 1 dB Steps

A 50 Ω push-button step attenuator covering DC–3 GHz with 0–90 dB in 1 dB increments, using eight la…