Start with the symptom. Follow the checks, record the evidence, and use each result to choose the next action.
For deployed personnel, workshop support and training. Generic equipment guidance; use the limits and procedures for your actual system.
Choose a roadmap
Unsure where to start? Use FF-01.
FF-01 · Start here: isolate the fault
No service, an intermittent fault, or an unclear starting point.
3 checks with result-based next actions.
FF-02 · Linux connectivity & tracing
A Linux device cannot reach a network, hostname or application.
7 checks with result-based next actions.
FF-03 · RSSI, noise & link quality
Weak received signal, poor throughput, retries or an unstable RF link.
3 checks with result-based next actions.
FF-04 · VSWR & reflected power
A mismatch alarm, high reflected power or a suspected antenna / feeder fault.
3 checks with result-based next actions.
FF-05 · Antenna placement & alignment
Reduced signal after installation, movement, weather or a site change.
3 checks with result-based next actions.
FF-06 · Cables, connectors & dB loss
Damaged connections, intermittent service or unexplained signal loss.
5 checks with result-based next actions.
Use the same method in the field or workshop
Deployed
Start with read-only checks. Record the fault before a restart, protect the working management path, and agree an outage window for disruptive tests. Print or save the relevant roadmaps as PDFs before leaving connectivity.
Workshop / non-deployed
Reproduce the symptom with a known-good configuration, compatible spare cables and rated test loads. Change one item at a time and record the original and replacement results.
Use the equipment manual and local operating procedure for limits and permitted work. Missing tools or measurements are an unknown result: collect what is available and escalate with that gap recorded.
Using these guides offline
Use your browser’s Print command to print or save a PDF. Print any linked roadmap you may need: a saved individual page does not include the other guides.
Related: Build guides and technical manuals · RF lessons · RF link-budget calculator
Reference content: revision 1, 15 September 2026. These generic decision guides have been source-reviewed; THL has not hardware-tested every procedure on your equipment.