What are the two types of measurement devices used to determine antenna coverage, and what are their trade-offs?
Passive signal measurement returns a list of visible cells but says nothing about whether a connection is possible; active connection actually connects to antennas and returns cells where a connection is genuinely possible, but is far less efficient and needs a SIM per provider. Neither list is necessarily complete.
The two types:
| Type | Returns | Trade-off |
|---|---|---|
| Passive signal measurement | A list of visible cells | Gives no information about whether a connection is actually possible |
| Active connecting | A list of cells where a connection is possible | Massively less efficient; needs a SIM card per provider |
The key distinction: visible ≠ connectable. A passive scan might detect a cell's signal, but the device might not actually be able to register/connect to it (e.g., it's a different operator, or signal too weak for a stable link). Active measurement answers the connection question directly — at the cost of speed and needing SIMs for every operator.
The shared caveat:
- Neither list is necessarily complete — measurement can miss antennas
Why this matters: measurement is the recommended approach (since prediction fails), but the tools themselves are imperfect. An incomplete list means you might miss the very antenna the suspect's device actually used — a limitation that must be acknowledged rather than glossed over.
Tip: Passive = fast but "visible only"; active = realistic but slow and SIM-hungry. And remember: neither is guaranteed complete.
Go deeper:
Drive testing (Wikipedia) — the field-measurement methodology for real cellular coverage, passive scanning vs active connected measurement.