When clamping RF cables, what are the determining factors when selecting the clamp?

• A. The clamp must fit without crushing the cable.
• B. The clamp should be painted orange for visibility.
• C. The clamp should be as light as possible to minimize weight.
• D. The clamp must fit without crushing the cable and must be snug enough to prevent movement while allowing slight axial sliding.

Answer: (D)

When selecting a clamp for RF cables, the key idea is to balance secure restraint with gentle handling of the cable. The clamp should grip the cable firmly enough to prevent movement along the aircraft structure, but it must not crush or deform the outer jacket or the dielectric. Allowing a small amount of axial sliding is essential because it lets the cable accommodate thermal expansion, vibration, and bending without transferring stress to the connector or damaging shielding.

If a clamp crushes the cable, insulation or shielding can be damaged, changing impedance and increasing the risk of failure. If it’s too loose or rigid and doesn’t permit any sliding, stress builds up at the connector and along the run, especially under flight-induced movement and temperature changes. Those forces, if not managed, can lead to wear, shorts, or impedance disturbances.

Colors or weight are not the determining factors here; the priority is preventing damage while controlling movement and allowing a bit of axial movement for real-world conditions.