LoRa mesh planner: nodes, links, hops
A LoRa mesh network carries text messages and positions without mobile networks if every node reliably reaches at least one neighbour. The Signal-Pirat mesh planner takes a list of nodes with coordinates, antenna height and antenna gain, calculates every link between two nodes and shows which nodes are reachable within the hop limit and where the network depends on a single node.
Open in the browser
No installation, no sign-up needed.
What the page does
- Links per node pair: distance, free-space loss, received level and margin
- Radio horizon from antenna height and terrain difference, first Fresnel zone at mid-path
- Meshtastic presets for 868 MHz, free values for MeshCom on 433 MHz
- Relaying over all nodes or only over repeaters as in MeshCore
- Bottlenecks: nodes whose failure splits the network
- Check of the 27 dBm ERP limit in the 869.40 to 869.65 MHz sub-band
Background
The sensitivity of a LoRa receiver follows from thermal noise, bandwidth, noise figure and the signal-to-noise ratio still allowed by the spreading factor; at spreading factor 11 and 250 kHz bandwidth this gives about minus 131 dBm. Free-space loss grows by 20 dB per tenfold distance. Terrain, forest and buildings add further loss; the planner covers this with a freely chosen planning margin. Beyond the radio horizon a link usually does not work, so the antenna height above terrain matters more than transmit power. Meshtastic relays packets over every node, MeshCore only over nodes in the repeater role; MeshCom is an amateur radio network on 433 MHz and requires a licence.
In practice
How it works: enter nodes with name, coordinates, height above ground and terrain height, or load the example network. Choose band and preset, enter transmit power and antenna gain and set a planning margin. The sketch shows viable links, the number at each node the hops from the start node, a red ring marks a bottleneck. Plan a second repeater at a bottleneck or mount the antenna higher. Save the plan as a file and confirm it with an on-site measurement before installation.
Frequently asked questions
Does the planner replace a terrain calculation?
No. It calculates in free space with the radio horizon; terrain, vegetation and buildings are part of the planning margin. For single links the platform's terrain profile helps.
Are my nodes transmitted?
No. The node list stays in the browser and can be saved as a file.