The key idea

RSSI describes received signal strength; it is not an internet speed result.

Read the sign correctly

Wi-Fi signal measurements are commonly displayed in dBm. Within the negative values normally seen in a Wi-Fi scan, a value closer to zero represents a stronger received signal. For example, −45 dBm is stronger than −75 dBm. The minus sign is part of the measurement, not a formatting detail.

The scale is logarithmic. A change of ten dB is not a ten-percent change in power. For practical survey work, focus on consistent comparisons and the needs of the device and application rather than treating a label such as “excellent” as a universal guarantee.

Compare like with like

A useful comparison holds the device, location and selected network reasonably steady. Moving the phone, changing its orientation or measuring another BSSID can change the result. A single difference between two visits does not automatically mean the infrastructure has deteriorated.

Keep the underlying readings accessible. A summary can help you find an area to investigate, but it should not hide the point-level values that produced it. When several radios share a network name, identify the radio you are comparing.

What RSSI does not answer

A strong received signal does not establish available airtime, internet capacity, packet delivery or application response. A user can see a strong signal and still have a slow call or download. Conversely, one weak reading does not explain every symptom in that room.

Separate your questions. Use signal observations to examine the spatial pattern, and use suitable connection or application tests for performance questions. Record what each test actually measures so readers do not mistake one type of evidence for another.

Use the number to choose a next step

Look for repeatable changes along a route: a particular room, corridor transition or workstation may deserve closer inspection. Repeat a suspicious point before making a major change, and compare the same position after any adjustment.

Wi-Fi Master Planner keeps the captured signal observations tied to deliberate floor positions. Use that relationship to explain where the evidence came from. Do not present unmeasured parts of the floor as though a reading was collected there.

Take it into the field

  • Keep the minus sign when sharing dBm values.
  • Compare the same BSSID and similar device conditions.
  • Treat signal and throughput as separate measurements.
  • Check individual points before interpreting a summary.

Put your next survey on the map.

Prepare a floor on the web, capture deliberate points on Android and review the observations in one place.

Create free account Explore the workflow