Signal & link budget
Convert dBm and mW, estimate Wi-Fi signal strength through walls, and check whether a fibre link has enough optical power left.
dBm ↔ mW
Every +3 dB doubles the power, every +10 dB multiplies it by ten.
Free-space path loss
Band
Wi-Fi link: what signal will the client see?
Obstacles in the way
Signal at the client by distance
Hover to read the signal at any distance; click or drag to set the distance. With the keyboard, focus the marker and use the arrow keys.
Free-space maths plus typical wall losses. Real rooms add reflections and furniture, so treat it as a planning estimate and verify with a survey.
Fibre link: enough light left?
Optics
Where the light goes
Margin keeps a 3 dB reserve for ageing, dirty connectors and repairs. Connector 0.5 dB and splice 0.1 dB are common planning values; use your measured figures when you have them.