Ham Radio

Ham Radio

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When the grid fails, radio operators become the last information network

Your comprehensive guide to radio frequencies, protocols, and the tools to explore them.

Ham Radio Protocols

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The lineage runs deep - Army Signal Corps, 1940s

GMRS (General Mobile Radio Service)

Frequency allocation: 462-467 MHz, 22 channels total. Channels 1-7 and 15-22 allow up to 50W, channels 8-14 limited to 5W.

Repeater pairs: Channels 15-22 use +5 MHz offset (input 467.550-467.725, output 462.550-762.725).

Licensing: $35 FCC registration, no examination required, 10-year term covers immediate family.

CTCSS/DCS: Privacy codes prevent interference but don't provide security - all transmissions remain receivable.

Amateur Radio Fundamentals

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Yaesu FT-857D - all bands, fits in a go bag

2 meters (144-148 MHz): Most popular VHF band. Repeater outputs 144-145 MHz, inputs 145-146 MHz with +600 kHz offset. Simplex operation on 146.52 MHz (national calling frequency).

70 centimeters (420-450 MHz): UHF band with +5 MHz offset for repeaters. Regional variations exist - West Coast often uses -5 MHz.

6 meters (50-54 MHz): "Magic band" with sporadic E propagation enabling 500+ mile contacts during openings.

License progression: Technician (VHF/UHF privileges, limited HF), General (most HF bands), Amateur Extra (full privileges including exclusive subbands).

Exam structure: 35 multiple choice questions, 74% passing score. No Morse code requirement since 2007.

Mesh Networking

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LoRa - the protocol that lets you ping friends across valleys

Meshtastic: LoRa modulation on 915 MHz (US), 868 MHz (EU), 433 MHz (Asia). Spreading factors SF7-SF12, higher SF = longer range but slower data rate. AES-256 encryption with rotating keys.

Hardware: ESP32-based nodes, typical 1-10km range depending on terrain and antenna height.

Protocols: Position sharing, text messaging, sensor data relay through multi-hop mesh.

AREDN (Amateur Radio Emergency Data Network): High-speed mesh on 2.4/5.8 GHz using modified OpenWrt firmware. IP networking over amateur frequencies enables video, VoIP, file sharing.

Equipment: Ubiquiti devices flashed with AREDN firmware. Bandwidth up to 150 Mbps depending on modulation and channel width.

ATAK Integration

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Cursor-on-Target - military SA goes civilian

TAK (Team Awareness Kit): Military-derived situational awareness platform using Cursor-on-Target (CoT) messages in XML format.

Data sources: GPS positions, imagery, chat, file sharing.

Radio integration: APRS position feeds, voice coordination on amateur frequencies.

Mesh compatibility: Operates over any IP network including AREDN mesh nodes.

Plugin architecture: Supports various radios through TAK server or direct integration. Amateur radio provides backup when primary data links fail.

The Real Value

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When everything else is noise, the spectrum speaks truth

Radio isn't about the technology. It's about information independence. When networks fail, when infrastructure crumbles, when algorithms control what you see - radio remains. No servers. No accounts. No terms of service.

Just you, the ionosphere, and whoever else is listening.