A rotary step attenuator changes RF attenuation in discrete increments through a mechanical dial. It is useful when a test needs several repeatable signal levels.
How it works in practice
Each dial position selects a different attenuation state. The stated range describes selectable nominal attenuation, while insertion loss, matching and accuracy remain frequency dependent. Check whether the scale represents additional attenuation or total measured insertion loss. Mechanical switching also has a finite operating life.
Example and interpretation
A 0–90 dB unit with 10 dB steps provides nominal settings at 0, 10, 20 dB and so on, subject to the specified accuracy.
Checks before use
- Check range and increment
- Identify the zero reference
- Confirm input power at every state
- Record the selected setting
Important limit
A zero setting does not guarantee a lossless connection.
Related Centron RF product
SMA rotary attenuator with 10 dB steps. The linked rotary model lists 0–90 dB adjustment in 10 dB steps, 50-ohm impedance and a DC–6 GHz band. Its listed continuous input is 2 W; obtain explicit switching and pulse limits before applying those stresses.
Further reading
Keysight: Accurate Network Measurements. This background reference explains general principles; the selected Centron RF model’s datasheet governs its own ratings.
Related guides
- Rotary Attenuator Range Versus Resolution Explained
- How to Run a Receiver Sensitivity Sweep with a Step Attenuator
Educational guide. Numerical examples use the stated assumptions and are not test results for a supplied unit.