How do I tell whether a bad reading comes from the RF test cable?

Three checks. Substitute a known-good cable first — it separates the cable from the equipment fastest. Then look and feel: inspect the connector root and any point where the cable is bent repeatedly, and work along the length for wear, kinks, or jacket damage. Then measure: compare insertion loss and VSWR against the cable’s baseline. A 60 cm cable should show about 0.85 dB at 3 GHz and 1.2 dB at 6 GHz; clear degradation means replace it. A cable that cuts in and out should be reproduced with a flex test and then taken out of service.

Key points

• Substitute a known-good cable first to isolate the fault
• Inspect the connector root and stress points along the length
• Compare against baseline: about 0.85 dB at 3 GHz and 1.2 dB at 6 GHz over 60 cm
• Flex-test intermittent cables, then withdraw them from service
• Log cable replacement dates so age-related failures become predictable

Products this applies to

QT Lab-TS405

RF Test Cable QT Lab-TS405, 800 MHz–6 GHz

A 50 Ω RF test cable from 800 MHz to 6 GHz with SMA male to right-angle SMA male connectors, 0.85 dB…