Mesh settings QR

Everything runs in this page — nothing is uploaded, and it works offline once loaded.

Generates a meshcore://radio/set code that MeshCore Hardened can scan to join your area's mesh.

Start from Preset

Mesh Name shown when scanning

Radio

Frequency (MHz)

Bandwidth (kHz)

Spreading factor

Coding rate (4/x)

Path hash width

Flood region (optional)

Your saved settings

Kept in this browser only (local storage) — handy while you are experimenting. Nothing is sent anywhere, and clearing site data removes them.

Import from file

Transmit power is deliberately not included. Every radio field above is “match this or you are not on the mesh”. Power is not — it is the legal limit where the scanner is standing and what their hardware can do. Nor are channel keys: this is a config code, not a secret, so it is safe to print and post.

These are settings a community has agreed on, not legal advice. Frequency and duty cycle are regulated where you are, and getting them wrong is an offence in most places.

Apply over USB

Plug a repeater, room server or companion node into this computer and write the settings straight to it — no QR, no radio link. Over USB the node takes commands without a login, because physical access already is the credential; it is also the safest place to retune a node, since a mistake is recoverable by unplugging it rather than by driving to a hilltop.

Code

The image carries the settings as readable text underneath, so a printed code still says what it does.

What a receiver can still hear, and how much loss a link can absorb getting to it. This is a calculator, not part of the code you hand out — nothing here goes into the QR.

Receiver sensitivity

Sensitivity does not depend on frequency. It is set by bandwidth and spreading factor alone: thermal noise in the channel, plus the receiver's noise figure, plus how far below the noise that spreading factor can still decode. S = −174 + 10·log₁₀(BW) + NF + SNR_min, with NF taken as 6 dB. Frequency changes how much signal survives the journey, not what the far end can hear when it arrives — which is why there is no frequency column below.

At 125 kHz this lands on the SX1262 datasheet's typical figures across SF7–SF12. SF5 and SF6 are extrapolated from the same 2.5 dB spacing and are the optimistic end of the table, not measured values.

Sensitivity (dBm) Path loss the link absorbs (dB) Airtime, 100 bytes (s)

Your hardware

Only used for the path-loss view. These four numbers describe your radio, not the mesh — they are not in the QR code, not written to a node over USB, and not part of a saved or exported setting. They stay in this browser.

Transmit power (dBm)

Antenna gain, sender (dBi)

Antenna gain, receiver (dBi)

Cable and connector loss (dB)

Reading it

There is deliberately no distance here. Turning path loss into range needs terrain, antenna height and clutter; a free-space figure at these budgets comes out in the thousands of kilometres, which is worse than no answer. Use the decibels instead — 6 dB is twice the distance in free space and rather less than that in the real world.

The path-loss figure is a ceiling with no fade margin: a link sitting exactly on it does not survive rain, a passing truck, or the leaves coming out. Real deployments plan 10–20 dB below it.

Sensitivity on its own always says "use SF12", which is true and useless. Switch to the airtime view and the trade becomes visible: every 2.5 dB of reach costs roughly double the time on air, and the air is shared with everyone else on the mesh.