Plain-language definitions of the terms you’ll meet in Meshtastic, with WiFi and Bluetooth comparisons where they help.
| Term | Meaning |
|---|---|
| Airtime (TX utilisation) | Share of time a node spends transmitting. Shown as “Airtime used to send” in the panel. |
| Bandwidth (BW) | How wide a slice of spectrum each transmission uses; 250 kHz on LongFast. Wider is faster but shorter range. |
| Channel | A named group with its own encryption key, like a WiFi network name plus password. The default primary channel has an empty name (shown as LongFast) and a public key. |
| Channel utilisation | Share of time the radio hears any LoRa traffic. Shown as “Channel busy”; above about 25% the mesh is getting crowded. |
| CLI | The meshtastic command-line tool from the Python library. |
| Duty cycle | A legal limit on how much of the time you may transmit. NP_865 allows 100%; some EU bands allow only 1–10%. |
| Firmware | The software on the board. Flash it with the web flasher; keep all boards on the same version. |
| Hop / hop limit | One relay by another node. The hop limit (default 3) caps how many times a message is relayed. |
| ISM band | Licence-exempt radio bands such as 2.4 GHz (WiFi/Bluetooth) and sub-GHz bands like 865–868 MHz, subject to national rules. |
| LoRa | “Long Range”: a chirp spread-spectrum radio method from Semtech; slow but very long-range and low-power. |
| LoRaWAN | A different, operator-run network protocol built on LoRa radios. Meshtastic does not use it. |
| MAC address | The hardware address of the board’s WiFi or Bluetooth radio. ESP32 nodes derive their node ID from it. |
| Mesh | A network where every node can relay messages for others, with no central router. |
| Modem preset | A bundle of LoRa settings (bandwidth, spreading factor, coding rate). LONG_FAST is the default. |
| MQTT | A lightweight publish/subscribe protocol. Nodes can uplink packets to mqtt.meshtastic.org for maps and tools. |
| Node / node ID | One Meshtastic device; its ID looks like !a1f80938. |
| NodeInfo | A packet announcing a node’s name and hardware model. Until it arrives, other nodes only know the ID. |
| OK to MQTT | A setting (lora.config_ok_to_mqtt) that lets your packets be published to MQTT by any gateway. meshmap.net requires it. |
| Paxcounter | An ESP32 module that counts nearby WiFi and Bluetooth devices and broadcasts the totals. See Paxcounter. |
| PKC | Public-key cryptography, used for direct messages since firmware 2.5 (hasPKC: True). |
| Position precision | How much a shared location is blurred. Lower bit values mean a bigger blur; meshmap.net needs between about 364 m and 23.3 km. |
| PSK | Pre-shared key: a channel’s encryption key. default / AQ== is the public default key. |
| Region | Which band and power rules the radio follows. Nepal: NP_865. |
| RSSI | Received signal strength in dBm. Closer to 0 is stronger; about −120 dBm is near the limit. |
| SNR | Signal-to-noise ratio in dB. LoRa decodes below the noise floor, so negative values are normal. |
| Spreading factor (SF) | How much each bit is spread out in time. Higher SF gives more range and less speed; LongFast uses SF11. |
| SX1262 | The Semtech LoRa radio chip on both boards in this project. |
| Telemetry | Packets with battery, voltage, channel use or sensor readings. |
| U.FL / IPEX | The tiny snap-on antenna connector on both boards. Press it straight down until it clicks. |
| Uplink / downlink | Uplink sends mesh packets to MQTT; downlink brings MQTT packets back onto the mesh. |