Nine real failure scenarios — weak signal, high VSWR, interference, multipath, misalignment, Wi-Fi congestion, cellular performance, microwave, and satellite outages — each built around measuring first, not guessing.
"Swap the radio and see if it clears up" is a technician's move, not an engineer's — it treats the symptom as the problem. This module builds the opposite discipline: measure first, form a hypothesis consistent with those measurements, then test it with a targeted change. It walks through weak-signal and coverage-gap complaints where the instinct to add transmit power almost never actually fixes a degraded connector or a mispointed antenna; high VSWR and poor return loss, where a weather-correlated reading points toward water ingress rather than a hardware defect; and RF interference, where a spectrum analyzer distinguishes an ordinary co-channel interferer from an intermodulation product generated at a corroded connector or rusted tower hardware.
It continues through multipath fading (and why more transmit power doesn't fix a destructive-combination null the way antenna diversity or MIMO does), antenna and point-to-point alignment errors that cost link margin a few degrees at a time, Wi-Fi congestion and airtime contention hiding behind a perfectly strong RSSI reading, cellular problems where SINR and cell loading explain "good bars, bad performance" far better than signal strength ever will, and microwave and satellite link failures — rain fade, path obstruction, and even predictable solar transit — diagnosed by what changed on a previously stable link rather than a full re-verification from scratch.