ValidatedModel against measurement
A model on SeeFields earns the Validated badge only when a measurement in a real room agrees with it, by a rule written down before anyone measures. This page holds the rule, the way to measure, the published results and a tool to check a measurement.
Status
No measurement has been published yet, so no model on SeeFields carries the Validated badge.
The rule
A phone reports Wi-Fi signal strength (RSSI) with an offset nobody publishes: the router's power, the phone's antenna, the hand holding it and the chipset's calibration all shift it. So SeeFields never compares absolute dBm. It compares what that offset cannot touch:
| Test | What is compared | Passes when |
|---|---|---|
| Distance sweep | How the received power falls with distance. One constant offset is fitted and removed; what remains is the shape: the 1/d² slope with the ripples of the floor reflection. | residual RMS ≤ 3 dB, at least 6 readings, the farthest at least 4× the nearest |
| Wall | The same spot with and without the wall. The offset cancels in the difference, which is compared with the ITU-R P.2040 slab loss at the measured thickness. | mean difference within ±3 dB of the model, at least 3 spots |
The model is the room's own physics core, unchanged: the half-wave dipole's antenna tip to the phone in 3D, free-space loss, and the two-ray floor reflection with Γ∥ (see About and models). Readings at or below −88 dBm are left out: that is where phones stop reporting reliably.
A pass means the model agreed with that room, at that frequency, within that margin. It does not make the model exact and does not carry over to other materials, frequencies or rooms. The badge is given per model and per condition, and the data is published with it.
How to measure
What you need
- A Wi-Fi router on a fixed 2.4 GHz channel, 20 MHz wide, antenna vertical. Turn off automatic channel selection and band steering so the phone stays on 2.4 GHz, and note the channel.
- A phone app that shows the connected network's signal in dBm. On Android, for example the open-source WiFi Analyzer; turn off "Wi-Fi scan throttling" in Developer options, or readings update only a few times a minute. On iPhone, the Wi-Fi scanner in Apple's AirPort Utility (switch it on in Settings).
- A tape measure.
Every reading
- Hold the phone upright at arm's length in front of you, at the same height every time, and face the router, so your body stays behind the phone.
- For about 20 seconds move the phone slowly round a 30 cm circle and note about ten readings. In the check below, type them one after another into the spot's field (
-52 -54 -53): it keeps their mean, the countn, the spreadsd_dband the readings themselves. The circle averages out the fine multipath pattern, whose scale is half a wavelength (6 cm at 2.4 GHz). - Nobody walks between the router and the phone while you read.
Distance sweep
- A large open floor: an empty hall, a car park, a concrete yard. Stay at least 3 m from walls, cars and metal; the comparison model has the floor and nothing else.
- The router's antenna tip at a measured height (for example 1.2 m on a stand), the phone at a measured height (for example 1.1 m).
- Readings at the template's distances, 1 m to 10 m, measured horizontally from the antenna.
Wall
- A wall of a material the model knows (concrete, brick, plasterboard, wood, glass) whose thickness you can measure. Reinforcing bars, pipes and cables inside change the result; note them.
- Router 2 m from one face, phone 2 m from the other, both on the line perpendicular to the wall.
- Keep doors, windows and other openings away from that line: for 20 cm concrete at 2.4 GHz over 4 m, at least 2.5 m. A wave bending round an opening can arrive stronger than the one through concrete. The check below prints this distance for your wall.
- Then the same distance and heights with nothing between: that is the
nonereading of the pair, with the same spot label. Three spots or more along the wall.
Download the template (CSV) or load it straight into the check below.
File format
# channel: 6or# f_mhz: 2437: the router's frequency.# tx_height_m: the router's antenna tip above the floor;# rx_height_m: the phone.# floor: concrete (default), metal, or none to leave the floor reflection out.# dipole: on (default) or off.- Optional notes:
# date,# place,# instrument,# router,# phone. - Columns:
scenario(distance or wall),pos(spot label; pairs the wall readings),d_m(horizontal distance),wall(none, concrete, brick, plasterboard, wood, glass, metal),thickness_m(the wall's, optional),rssi_dbm(empty until measured),n,sd_db,note. - A file saved by Excel with semicolons and decimal commas is read as well.
Check a measurement
Load the template, type each reading as you take it, and the comparison updates at once. It runs in your browser: nothing is uploaded, and the draft stays on this device. A local check does not award the badge; a measurement is published on this page together with its data.