Signal range mapper

Approximation, not a survey

Using the mapper

The plan above is a flat, top-down sheet measured in metres. The rulers along its edges count metres from the top-left corner. Everything is approximate, and the numbers are for comparing options, not for promising anyone a speed.

How to use it

Pick the plan area and band. The example flat is already loaded.
Choose Draw wall and a material, then drag across the plan. Hold Shift to lock to horizontal, vertical or 45 degrees.
Choose Access point. Click to place one (up to three), drag to move it, or type exact coordinates in the readout panel.
Hover or arrow-key around with any tool to read the dBm, the quality band and what the signal had to cross.
Change a wall’s loss, the band or the power, and compare the coverage percentages.
Export a PNG when you want to keep or share the result.

Assumptions

Signal travels in a straight line from each access point; every wall it crosses subtracts that wall’s loss once, whatever the angle or thickness.
Antennas are 0 dBi and radiate equally in all directions. The power you enter is the effective radiated power.
Each point on the map shows the strongest access point. There is no interference, channel overlap or client load.
The material losses are round, illustrative numbers at 2.4 GHz, scaled by 1.25 at 5 GHz and 1.4 at 6 GHz. Edit them to match what you know.
Anything below −95 dBm is drawn as no signal.

Edge cases

A click without a drag draws nothing. Walls shorter than 0.5 m are ignored.
Overlapping walls each count, so draw one long wall rather than two on top of each other.
The limits are three access points and 150 walls; the tool says so when you reach them.
Shrinking the plan area removes walls that fall outside it. Undo brings them back.
Power outside 1 to 30 dBm is clamped; text that is not a number is refused with a message.
On touch screens the drawing tools take over the plan. Switch to Inspect to scroll past it.
If the browser blocks storage, everything still works but nothing is remembered between visits.

Keyboard and pointer

Focus the plan by tabbing to it. A cursor appears; it moves in 0.5 m steps. Every pointer action has a keyboard twin.

`←` `→` `↑` `↓`	Move the cursor 0.5 m. Hold `Shift` for 2 m. The readout follows the cursor.
`W` `E` `A` `I`	Switch to Draw wall, Erase, Access point or Inspect.
`Enter` or `Space`	Draw wall: set the start, then press again to finish the wall and continue from there (press twice on the same spot to stop). Erase: remove the nearest wall. Access point: place one, or pick up the one under the cursor and press again to set it down.
`Delete`	Remove the access point or wall under the cursor.
`Esc`	Cancel the wall in progress, or put a picked-up access point back.
`Ctrl`/`Cmd` + `Z`	Undo the last change to walls or access points.
Pointer	Drag to draw a wall, drag across walls to erase, click empty space with the access point tool to place one, drag an access point to move it.