When conducting antenna-coverage measurements for an investigation, how many measurement cycles are needed, and where and when should you measure?

The number of cycles depends on the device and location (lakeside is especially hard) — even after 15 cycles new antennas can still appear, so it's unclear when all relevant antennas have been seen. Measure where the suspect provably was (and surroundings), and under conditions as close as possible to the time of the crime.

How many cycles you need depends on the measurement device and the location, with lakeside locations being particularly difficult. The sobering finding is that even after 15 measurement cycles, new antennas can still turn up — so it is hard to get a truly complete picture, and currently unclear at what point all relevant antennas have been observed. You stop on a practical judgement, not a guarantee.

Where you measure should be the places the suspect provably was — the crime scene, the access routes, and locations named in witness statements — plus the surrounding area. Widening the area raises the chance of a genuine "hit" but also increases false positives, so it is a deliberate trade-off.

When you measure should be under conditions as close as possible to the time of the crime, because the network is a moving target: operators optimise it for user load, switch antennas on and off, and a busy cell shrinks its own coverage (cell breathing). An antenna's location or ID can change, and there are even mobile antennas. So you try to match the weekday, time of day, weather, and holiday/vacation period of the original event. All of this rigour exists because cell-location evidence is only as good as the measurements behind it — measure at the wrong time or place, or stop after too few cycles, and the picture can wrongly include or exclude a suspect.

Tip: "Measure where they certainly were, when conditions match the crime, and accept you may never see every antenna." Cell breathing and mobile antennas are why timing matters.