How does connector torque affect RF performance and what is the correct torque specification?
Connector Torque Best Practices
The mating interface of a coaxial connector is a precision mechanical junction where the center conductor pin contacts the socket and the outer conductor shells make contact through the coupling mechanism. The quality of these contacts determines the electrical performance at the interface. Consistent torque produces consistent contact quality, which enables repeatable measurements.
| Parameter | Semi-Rigid | Conformable | Flexible |
|---|---|---|---|
| Loss (dB/m at 10 GHz) | 0.8-2.5 | 1.0-3.0 | 1.5-5.0 |
| Phase Stability | Excellent | Good | Fair |
| Bend Radius | Fixed after forming | Hand-formable | Continuous flex OK |
| Shielding (dB) | >120 | >90 | >60-90 |
| Cost (relative) | 2-5x | 1.5-3x | 1x |
Frequently Asked Questions
Do I need a torque wrench for every connection?
For measurements: yes, always. For permanent installations: yes, for the initial assembly. For bench testing and prototyping: a torque wrench is recommended but finger-tight connections are acceptable if measurement accuracy is not important.
Can I reuse damaged connectors?
Connectors with visible damage (bent pins, scored threads, galled surfaces) should be replaced. Damaged connectors cause irreproducible performance and can damage the mating connector. Use a connector gauge to verify pin depth after suspected damage.
What about different connector genders?
Torque is applied to the coupling nut (on the female connector for SMA/3.5mm/2.4mm, on the male for N-type). The body of the other connector must be held stationary. Never apply torque to the connector body or cable; this twists internal components and damages the cable.