MeshCore, send messages without internet

What's is MeshCore?

MeshCore is a way to send short text messages via LoRa radio. LoRa is designed for short messages over long distances with low power consumption. The key difference with a walkie-talkie is that you don't need to "hear" each other directly. Nodes can relay messages, allowing you to go further with multiple hops than with a single transmitter.

Think of a relay: your message jumps from node to node until it reaches the recipient.

Why would you want MeshCore?

• No internet required: also works when mobile coverage is lost or not used consciously
• Greater range via repeaters: one well-placed repeater can connect an entire area
• Low power consumption: ideal for battery, power bank and solar panel
• Community network: you build a comprehensive network together (club, village, event, etc.)

MeshCore isn't a replacement for the internet, smartphones, or tools like Signal. It's intended for simple, robust communication when you don't want or can't use infrastructure.

Currently, a MeshCore device should be included as standard in an emergency kit ;-)

How does a MeshCore network work?

There are three MeshCore rolls:

Repeater (the "bridge" of the network)

• • Usually fixed and preferably positioned high
  • Function: listen + forward,must run reliably and 24/7 if possibleand preferably powered by a solar panel in combination with a battery

Companion (your “user device”)

• • This is where you type and read messages
  • Can be a handheld node with phone, or a standalone device with screen/keyboard

Room (the “chat room” / meeting place)

Besides Repeater and Companion, there is also a Room node.

• • Function: Acts as a permanent “chat room” where messages are grouped together in one place, allowing multiple users to follow the same conversation (similar to a channel or group chat)
  • Usage: Useful for a community (e.g. “village”, “event”, “clubhouse”), because everyone knows where the conversations take place
  • Placement: like a repeater, ideally stable and often connected to a permanent power supply, but the emphasis is less on “highest spot” and more on “always online”
  • Important difference with repeater: a repeater is for the infrastructure (forwarding), a room is not necessary but can be useful

Minimum requirements to create a MeshCore mesh

• Minimum workable starter set
  • 1 repeater
  • 1 or preferably 2 companion nodes, so that you can test them against each other, with or without the repeater

Recommended hardware setup (other hardware is of course also possible)

Repeater

• • RAKwireless RAK4631 & RAK19007: modern, highly sensitive, and energy-efficient!
  • Outdoor antenna (preferably sturdy and suitable for 868 MHz): these are available in all shapes and sizes
  • Short coax/pigtail (shorter = less loss), as few connections as possible
  • Housing (weatherproof)
  • Power supply
    • Powerbank óf Li-ion/LiFePO4 pack
    • Solar panel + charge control (so it doesn't stop after 2 days)

Mounting: as high as possible, out of sight, away from metal and wet walls

Placement:

• • Height almost always trumps “more transmit power”.
  • A repeater 2–3 meters higher can make more of a difference than all sorts of settings

 Companion node: choice depending on what you want: built-in battery, antenna connection, screen or not, and ease of use

• • Optie A: Heltec v3 LoRa32
    • More modern
    • MeshCore support is better
  • Option B: T-Beam Neo6
    • Bluetooth range is significantly better than that of Heltec!
    • Not energy efficient
    • Very handy, I use it as a fixed node at home, connected via USB adapter
  • Option C: LilyGo T-Deck Plus (standalone chat device, nice to have) 
    • Screen + keyboard: feels like a real messenger
    • Ideal if you don't want to take a phone with you
    • Very suitable as a “community handheld” at events

Common Mistakes (and How to Avoid Them)

• Repeater placed too low → height and clear line of sight are more important than “another antenna”
• Too long coax → short cables, antenna close to the node or directly outside
• Inside the meter cupboard → demolish walls, concrete and metal range
• Wrong expectation → it's text, no voice, no pictures, no quick chat app
• Too complicated too fast → first get 1 repeater + 2 companions stable, then expand

Ok, does this sound like something you'd like?

That's great. Difficult? No, not at all. And luckily, there's a rapidly growing MeshCore community that's happy to help if you have any initial issues.

There are active MeshCore/Meshtastic WhatsApp groups, a Telegram group, and plenty of information about MeshCore can be found online!