Mesh Networks

What is a Mesh Network?

A communication network where each device connects directly to others, without needing a central server or internet. Messages hop from device to device until they reach their destination.

Key properties:

• Decentralized: No single point of failure
• Self-healing: If one node goes down, traffic routes around it
• Offline: Works without internet, cell towers, or infrastructure
• Scalable: More nodes = better coverage

Overview

Open-source mesh networking using LoRa (Long Range) radio. Devices text message each other over kilometers without any infrastructure.

Range: 1-5 km urban, 10-20+ km line-of-sight rural. With repeaters on hills, 50+ km.

Power: Devices run days on small battery, indefinitely on solar.

Cost: $30-50 per device

Hardware Options

• Heltec V3: ~$30. Popular, good community support. Built-in screen.
• Lilygo T-Beam: ~$40. Has GPS. Good for tracking.
• Rak WisBlock: ~$50. Modular, very low power, solar-friendly.
• Station G2: ~$80. Purpose-built, outdoor-rated, solar option.
• T-Echo: ~$50. E-ink display, very low power.

Source: Amazon, AliExpress, direct from manufacturers. Meshtastic.org has buying guide.

Setup

1. Install Meshtastic app on phone (Android/iOS)
2. Connect device via Bluetooth or USB
3. Configure region (US, EU, etc. - affects frequency)
4. Set your name/node number
5. Devices automatically mesh when in range

No license required for LoRa in most countries at low power. Frequencies vary by region - use legal channels.

Use Cases

• Group communication: Hiking, events, emergency response
• Community network: Neighborhood coordination
• Asset tracking: GPS-equipped nodes report location
• Sensor data: Temperature, humidity, etc. from remote sensors
• Emergency backup: When cell networks fail

Network Planning

• Nodes: Every participant is a node. More nodes = stronger network.
• Repeaters: Fixed nodes in good locations (hills, tall buildings) extend range.
• Gateways: Optional connection to internet allows messages to bridge to other networks.
• Channels: Different frequencies for different groups/topics.

Put a repeater on the highest point in your area. One well-placed node can connect an entire community.

Briar

Encrypted messaging app that works via Bluetooth and WiFi Direct. No internet needed. Messages hop through intermediate phones.

Pros: Works on existing phones, strong encryption

Cons: Short range (Bluetooth ~10m), requires phones to be near each other

Source: Free app. Briarproject.org

Bridgefy

Mesh messaging via Bluetooth. Works without internet. Used in protests when governments shut down networks.

Note: Not as secure as Briar. Use for non-sensitive communication.

WiFi Mesh

Standard WiFi equipment can create mesh networks:

• OpenWRT routers can mesh together
• Ubiquiti, MikroTik equipment supports mesh protocols
• Community networks (NYC Mesh, guifi.net) provide templates

DIY: Old routers with OpenWRT firmware. Directional antennas for longer links. ~$20-50 per node using used equipment.

License Required

Amateur radio requires license but provides:

• VHF/UHF: Local communication (2m, 70cm bands). 5-50 mile range with good antenna.
• HF: Long-distance (states, countries). 3-30 MHz bands. Skywave propagation.
• Repeaters: Existing infrastructure extends range.
• Modes: Voice, Morse code, digital modes (FT8, JS8Call, packet radio)

Source: Baofeng UV-5R ($25) covers VHF/UHF. HF radios $200-2000. License exam ~$15.

In emergency, anyone can use any frequency to save lives. But learn and license beforehand.

Digital Modes for Text

• JS8Call: Keyboard-to-keyboard messaging over HF. Works in poor conditions.
• VARA: Fast data over HF. Can send files.
• Packet radio: Older protocol, still works. APRS for position reporting.

OpSec for Communications

• Assume everything is monitored: Radio transmissions can be intercepted
• Use codes: Pre-agreed meanings that don't reveal sensitive info
• Direction finding: Radio transmissions can be located. Mobile is harder to find than fixed.
• Encryption: Ham radio cannot legally encrypt. Meshtastic can. Know the rules.
• Minimal transmission: Short messages, essential info only

Phased Approach

1. Start small: 2-3 nodes, test range in your area
2. Expand core: Get key people equipped (medical, security, leadership)
3. Add repeaters: Strategic high points extend coverage
4. Train everyone: Practice using devices before crisis
5. Document: Write down frequencies, protocols, backup plans

Protocols

• Check-in schedule: Daily at specific times
• Priority codes: Routine / Urgent / Emergency
• Acknowledgment: Receiver confirms message received
• Relay: If recipient not in range, others relay message

Running Without Grid

• Battery: USB power banks work for days
• Solar: Small panel keeps device running indefinitely
• 12V: Car battery or deep cycle with solar panel

DIY: 5W solar panel + USB power bank = indefinite operation. $20-30 total.