Observers

About observers

Observers forward the MeshCore packets they hear over MQTT to one or more brokers, which distribute them to tools such as:

• Analysis tools that show how packets, especially flood packets, move through the network, helping assess link reliability and possible coverage gaps.
• Mapping services showing repeater locations and coverage.

Finland provides a public MQTT broker for all observer operators. That page explains where packets are distributed.

Common misconceptions about observers

• Although observers use MQTT, traffic is one-way, from the radio network to the MQTT broker. Unlike Meshtastic, for example, we never bridge Internet traffic into the radio network.
• Not everyone needs an observer. If your mesh already has observers, you may not need your own.

Choosing an observer

There are many ways to build an observer. The most common approaches in Finland are listed below and explained further on:

• Dedicated Repeater + Observer firmware – repeaters with WiFi, usually ESP32 devices, can also act as observers. This is by far the most common and convenient option.
• MeshCore Packet Capture – flashing a debug build of MeshCore firmware lets a repeater or companion device also act as an observer.
• OpenHop Repeater – a repeater implemented in Python, running for example on a Raspberry Pi with a LoRa HAT.

A. Gessaman provides a comprehensive overview with links to observer options.

IATA codes

The observer system developed around the now-obsolete LetsMesh service and the popular MeshMapper service. For that reason, every observer must be assigned an operating area using an IATA code.

The code depends on location, but is not necessarily that of your nearest airport: it specifically identifies a MeshMapper region. Check the regions on MeshMapper.

Finland currently has these MeshMapper regions and corresponding IATA codes:

• HEL – Southern Finland
• JYV – Central Finland
• KOK – Ostrobothnia
• OUL – Oulu Province
• SJY – South Ostrobothnia
• TKU – Southwest Finland
• TMP – Greater Pirkanmaa

Some codes have no MeshMapper region yet but can still be used by observers:

• JOE – Eastern Finland
• RVN – Lapland

If your observer does not fit any of these areas, do not choose a random code. Ask the MQTT administrators to add a new area code. The broker only accepts codes that have been configured on it.

Observer Firmware

• No separate observer device is needed if you already have a suitable repeater.
• Continuous power is recommended because of WiFi power consumption.

Quick start:

• Flash your repeater using the Repeater Observer website.
• The device creates a WiFi network. Join it to access the straightforward web administration interface.
• Configure the basic repeater settings.
• Set your IATA code.
• Add meshcore-fi as the MQTT preset: this is our public broker.

MeshCore Packet Capture (MCPC)

• Works with almost any device; WiFi is not required.
• The device must remain connected to a computer.
• Requires a Python program running specifically for this observer function.

Installation instructions are on the MeshCore Packet Capture GitHub page.

MCPC settings:

Should work, but…

The settings below should be correct, but the author has not tested MeshCore Packet Capture for some time.

Connection and authentication settings for Finland’s public MQTT server:

Variable	Value
PACKETCAPTURE_MQTT1_SERVER	mc-mqtt.meshcore.fi
PACKETCAPTURE_MQTT1_PORT	443
PACKETCAPTURE_MQTT1_USE_AUTH_TOKEN	true
PACKETCAPTURE_MQTT1_TOKEN_AUDIENCE	mc-mqtt.meshcore.fi
PACKETCAPTURE_PRIVATE_KEY_FILE	/path/to/private_key_file

MeshCore Packet Capture needs your device’s private key to sign the MQTT connection password. We recommend storing the private key in a file rather than an environment variable.

OpenHop Repeater

• A complete MeshCore repeater running on your computer.
• Supports hardware such as Raspberry Pi LoRa HATs containing a radio without a microcontroller.
• Can also work with standard devices, for example through KISS firmware.

Should work, but…

The preset below should work, but the author has not tested it personally.

For OpenHop Repeater, add a new meshcore-fi.yaml file under presets/:

display_name: MeshCore Finland
website: https://meshcore.fi/
brokers:
  - name: meshcore-fi
    enabled: true
    host: mc-mqtt.meshcore.fi
    port: 443
    transport: websockets
    audience: mc-mqtt.meshcore.fi
    use_jwt_auth: true
    format: letsmesh
    retain_status: false
    neighbors: true
    tls:
      enabled: true
      insecure: false