The UK 868MHz Meshtastic Field Manual: Zero-Telecom Family & Business Comms

# OFF-GRID ACADEMY FIELD MANUAL 01 ## The UK 868MHz Meshtastic Field Manual: Zero-Telecom Family & Business Comms ### 1. Why Cellular Fails First in the UK Under Ofcom's current resilience framework, standard UK 4G and 5G Radio Access Network (RAN) mast sites have **no universal statutory mandate for multi-day battery backup**. Most urban rooftops carry 0 to 2 hours of battery reserve; rural masts average 2 to 4 hours. Coupled with the **2027 PSTN Switch-Off (Digital Voice)**, a regional National Grid disconnection silences both home fibre phones and mobile towers within 120 minutes. ### 2. UK Ofcom IR2030 Regulatory Parameters In the United Kingdom, Meshtastic operates legally without a licence under **Ofcom Interface Requirement IR2030** (Short Range Devices): - **Primary Meshtastic UK Frequency Slot:** `869.525 MHz` (within the 869.400–869.650 MHz sub-band) - **Maximum Permitted Power:** **500 mW ERP (+27 dBm)** with a **10% duty cycle** - **Modem Preset:** `LONG_FAST` (250 kHz bandwidth, Spreading Factor 11, Coding Rate 4/5) ### 3. Hardware Bill of Materials (BOM) 1. **Pocket Handheld Node (Per Person):** Nordic `nRF52840` (RAK4631) or `ESP32-S3` (Heltec V3) with Semtech `SX1262` transceiver + 3000mAh LiPo + tuned 868MHz SMA whip antenna (VSWR < 1.5:1). *Note: Never power on a node without its antenna attached, or reflected RF power will destroy the SX1262 front-end.* 2. **Rooftop Autonomous Repeater:** RAK4631 WisBlock core inside an IP67 polycarbonate box, 6W monocrystalline solar panel, 2x 18650 LiFePO4 cells (safe for sub-zero UK winter charging), and a 5.8 dBi fibreglass omni antenna mounted above the roofline. ### 4. Step-by-Step Encryption & OPSEC Configuration 1. Connect your node via USB-C to `client.meshtastic.org` (or the air-gapped local Web UI on your EOD Cyberdeck). 2. Navigate to **LoRa Config -> Region** and select `EU_868`. 3. Leave **Channel 0 (LongFast)** as default so your node participates in routing regional mesh packets, **but set Position Precision to Disabled or ~3km** on Channel 0 so strangers cannot pinpoint your house. 4. On **Channel 1**, create your private channel (e.g., `EOD-ALPHA`), generate a full **256-bit AES key (32 bytes)**, and enable precise GPS sharing *only* on Channel 1. Share the QR code air-gapped between family or staff phones. ### 5. Standard Operating Procedure (Blackout Comms Sked) - **Minute 0 of Mains Loss:** Turn on pocket nodes and hoist your portable window/chimney repeater node to maximum elevation. - **Top of Every Hour (H+00 to H+10):** All family/staff members check Channel 1 and transmit a structured 3-part welfare ping: `[CALLSIGN] [STATUS: GREEN/AMBER/RED] [BATTERY % & LOCATION]`.