📻 Communications & Signals

1. Ham Radio Basics

Amateur (ham) radio is the most robust communications infrastructure available in a collapse scenario. It operates across multiple frequency bands, can span from local neighborhood to intercontinental distances, requires no commercial infrastructure, and has an active global community of operators.

License Levels (USA)

Key Emergency Frequencies

HF Propagation Basics

• Ground wave: 160m–40m bands travel along the earth's surface. Range: 50–200 miles. Reliable and predictable.
• Skip/skywave: HF signals bounce off the ionosphere. Daytime: ionosphere is dense, 20m–10m bands skip further (10m can be global). Nighttime: lower frequencies (80m–40m) skip, high frequencies (20m–10m) may go dead.
• Practical rule: Use 40m or 80m at night for regional (100–1,000 miles). Use 20m or 15m during the day for long-distance (1,000–10,000 miles).

2. Baofeng Radio Setup Guide

The Baofeng UV-5R and UV-82 are inexpensive ($20–30), dual-band (VHF/UHF) handheld transceivers widely used in preparedness circles. They're not the best radios, but they're affordable, easy to acquire in quantity, and work well enough for local emergency communications.

Initial Setup

1. Charge the battery fully before first use (8–10 hours initial charge). The radio can be used while charging.
2. Install the antenna by threading clockwise until snug. Do NOT transmit without an antenna — it damages the final output transistor.
3. Set VOX off (Menu → 4 → 0). VOX (voice-activated transmission) causes accidental transmissions in noisy environments.
4. Set power to high (Menu → 2 → H) for maximum range in open terrain. Use low power in buildings to save battery.
5. Set squelch (Menu → 0 → 5). This mutes noise when no signal is present. Higher numbers = stronger signal needed to open squelch.

Programming with CHIRP (Recommended)

CHIRP is free open-source radio programming software. Much easier than programming channels manually via the keypad.

1. Download CHIRP from chirp.danplabell.us (or store on USB). Requires Python or standalone installer.
2. Connect radio to computer with the programming cable (USB to 2.5mm/3.5mm cable — must be Baofeng-compatible; cheap cables sometimes fail).
3. In CHIRP: Radio → Download from Radio. Select your model. Download current configuration.
4. Add channels: Name, frequency, mode (FM), tone (CTCSS if using a repeater), power level.
5. Radio → Upload to Radio. Disconnect cable and test.

Essential Frequencies to Program

• 146.520 MHz FM — National VHF simplex calling
• 446.000 MHz FM — UHF simplex calling
• FRS channels (462.5625–467.7125 MHz — receive only, no TX license needed for FRS)
• NOAA weather: 162.400, 162.425, 162.450, 162.475, 162.500, 162.525, 162.550 MHz (RX only)
• Your local repeater frequencies (find at repeaterbook.com or local ham club)
• MURS: 151.820, 151.880, 151.940, 154.570, 154.600 MHz (legal without license for business/personal)

Battery Life & Charging

• Standard battery: ~8–12 hours receive, 4–6 hours mixed RX/TX on high power.
• Charge from included USB charger or the drop-in charger. Both work with a 12V DC–USB adapter for solar/car charging.
• AA battery pack (sold separately) allows the radio to run on standard AA batteries — critical when lithium packs are dead and no charger is available. Slightly reduced TX power.

3. Morse Code Reference

International Morse Code Alphabet

A  · —      N  — ·
B  — · · ·  O  — — —
C  — · — ·  P  · — — ·
D  — · ·    Q  — — · —
E  ·         R  · — ·
F  · · — ·  S  · · ·
G  — — ·    T  —
H  · · · ·  U  · · —
I  · ·      V  · · · —
J  · — — —  W  · — —
K  — · —    X  — · · —
L  · — · ·  Y  — · — —
M  — —      Z  — — · ·

Numbers:
1  · — — — —    6  — · · · ·
2  · · — — —    7  — — · · ·
3  · · · — —    8  — — — · ·
4  · · · · —    9  — — — — ·
5  · · · · ·    0  — — — — —

Punctuation:
. (period)     · — · — · —
, (comma)      — — · · — —
? (question)   · · — — · ·
/ (slash)      — · · — ·
= (break)      — · · · —

Prosigns:
AR (end of transmission)   · — · —
BK (break)                 — · · · — · —
CQ (calling all stations)  — · — · — — · —
DE (from / this is)        — · · ·
K  (invitation to transmit) — · —
SK (end of contact)        · · · — · —
    

Sending Techniques

• Timing: Dot = 1 unit. Dash = 3 units. Space between elements = 1 unit. Space between letters = 3 units. Space between words = 7 units.
• Light signals: Flashlight, mirror, or signal lamp. Short flash = dot; long flash = dash.
• Sound: Knock on metal/wood. Short knock = dot; long knock = dash.
• Practice tip: Learn the 5 most common letters first (E, T, A, I, N) — they cover a high percentage of English text. Then add: O, S, R, H, L.

4. Visual Signals

Signal Fire

• Location: High point, open clearing, lakeshore, ridgeline — maximum visibility from air.
• Smoke production: Three fires in a triangle (10–30m apart) is the international distress signal. Produce white smoke (against dark background) with green leaves, grass, moss. Produce black smoke (against snow or pale sky) with plastic, rubber, oily rags. Maintain 3 fires simultaneously if possible.
• Prepare the fire in advance — have dry tinder and fuel ready to light instantly. A signal fire that takes 20 minutes to light after spotting an aircraft is useless.
• Signal fires work best in daylight with good visibility. At night, flames are visible; use sparingly to conserve fuel.

Mirror/Heliograph Signaling

A mirror flash can be seen 50+ miles away in clear conditions from an aircraft. It's one of the most effective signaling tools for search-and-rescue scenarios.

1. Hold mirror at arm's length. Tilt until sunlight reflected off the mirror creates a bright spot on your other hand or the ground.
2. Look through the mirror's sight hole (if present) and align the reflected sun spot with the target.
3. If no sight hole: extend two fingers in a V-shape toward the target. Tilt the mirror until the bright spot falls on your V. The mirror is now aimed at the target.
4. Flash in SOS pattern: 3 short, 3 long, 3 short. Even random flashes attract attention — just keep flashing when a target (aircraft, distant hilltop) is visible.

Ground-to-Air Signals

Create these signals in large, open areas visible from the air. Minimum size: 3 meters each character, 10+ meters preferred. Use rocks, logs, footprints in snow, or trenches to maximize contrast.

Other Visual Methods

• Bright fabric/tarp: Spread a bright-colored tarp (orange or yellow is most visible from air) in an open area. Rescue orange is internationally recognized as a distress color.
• Flagging tape: Mark your position and travel direction by tying bright flagging tape to trees at intervals. Searchers on foot or by air can track your movement.
• Chalk or spray paint on hard surfaces: Leave directional arrows and messages on rocks, roads, or walls in urban environments.

5. Mesh Networks — Meshtastic & LoRa

Meshtastic is an open-source project enabling encrypted text messaging over LoRa (Long Range) radio using inexpensive devices (~$30–60). It operates without internet, cell service, or any central infrastructure. Devices automatically relay messages through each other — the mesh extends as more nodes are added.

Key Characteristics

Recommended Hardware

• LILYGO T-Beam: Built-in GPS, Wi-Fi, Bluetooth. Best for mobile nodes. Flash with Meshtastic firmware.
• Heltec LoRa32 V2/V3: Compact, OLED display. Good for fixed nodes.
• RAK WisBlock: Modular, low power. Best for solar-powered permanent nodes.

Setup & Deployment

1. Flash Meshtastic firmware onto device (one-time, done before crisis on a computer).
2. Configure channel name and encryption key — all devices on your network must share the same channel settings.
3. Place nodes at elevated locations (hilltops, buildings, towers) to maximize range. Solar-powered nodes can run indefinitely.
4. Users connect via Bluetooth from smartphone (Meshtastic app) or serial terminal to their local node, which relays messages across the mesh.
5. Messages include: plain text, GPS position (optional), telemetry (battery level, signal strength).

LoRa Frequencies by Region

• US: 915 MHz (ISM band — license-free)
• EU: 868 MHz
• AU: 915/923 MHz
• Asia: 433 MHz or 470 MHz (varies by country)

6. NOAA Weather Radio

NOAA Weather Radio All Hazards (NWR) broadcasts continuous 24/7 weather information plus emergency alerts — including not just weather but also industrial accidents, nuclear plant issues, law enforcement alerts, and AMBER alerts.

NOAA Frequencies

• All Baofeng and most ham radios can receive NOAA. Program all 7 channels into memory.
• Dedicated weather radios (S.A.M.E. type) can be programmed to only alert for your specific county/region — reduces nuisance alerts.
• Battery backup or hand-crank weather radio is essential when grid power is down.
• The Emergency Alert System (EAS) tone — a distinctive digital tone followed by voice — precedes all emergency broadcasts.

7. Faraday Storage for Radios

Communications equipment is uniquely valuable in a crisis — and uniquely at risk from EMP. Store at least one backup radio of each type in a Faraday cage and don't open it until needed.

What to Store in a Faraday Cage

• 1–2 spare Baofeng or equivalent handhelds (in anti-static bags inside metal container)
• Spare batteries and battery packs (lithium batteries are not EMP-sensitive but their protection circuits can be)
• MPPT charge controller (for recharging radios after EMP)
• Handheld NOAA weather radio
• USB charging cables and adapters
• Programming cable and printed frequency list
• Meshtastic nodes

8. Dead Drop Communication

When electronic communications are compromised, monitored, or unavailable, dead drops (pre-arranged physical information exchange points) allow secure, asynchronous communication.

Basic Dead Drop System

1. Select locations: Pre-designate 3–5 drop locations known only to your group. Good locations are easily accessible, non-suspicious, and have natural concealment (under a specific rock, inside a hollow tree, behind a loose brick).
2. Establish signals: Use chalk marks, specific rock arrangements, or tied fabric to signal that a message is waiting at a specific drop. A mark at a pre-agreed location ("signal point") tells the recipient to check drop #2, for example.
3. Message format: Keep messages concise. Use pre-agreed codes where possible. Waterproof (wrap in plastic bag inside a small container).
4. Rotation: Use each drop only once per message cycle, then move to the next. Never reuse the same drop consecutively if operational security is critical.

Simple Cipher for Messages

A Caesar cipher (shift each letter by a pre-agreed number) or a one-time pad (random key agreed in advance, used once) allows basic message encryption without computers.

Physical Dead Drop Containers

• Film canister or pill bottle: Waterproof, small, easily hidden under rocks or in soil.
• Magnetic key holder: Attaches under metal surfaces (bridges, vehicles, fences).
• Sealed ziplock inside a rock: Faux rock containers blend into the environment.
• Hollow tree / bark crevice: Natural, blends completely — mark with a subtle signal only your group knows.

9. No-Power Radio (Crystal Set)

When the batteries are flat and the grid is gone, you still need to hear the world — emergency broadcasts, news, weather. A crystal radio (the old "foxhole radio") receives AM broadcasts using no battery and no power at all — it runs entirely on the tiny energy in the radio waves themselves. Soldiers built them from scrap in the trenches. It only receives, but information is survival.

What it needs (four parts)

1. A long antenna: as much wire as you can string up high and horizontal — 10–30 m. Longer and higher = louder. This is the single biggest factor.
2. A good earth (ground): a wire to a metal rod or pipe driven into damp soil, or to a cold-water pipe. The antenna and ground are the two "terminals" the radio works between.
3. A tuned coil: ~50–100 turns of insulated wire wound on a tube (a toilet roll, bottle, or can). A tap or a slider along the coil tunes to different stations.
4. A detector (the "crystal"): a germanium diode is ideal. The classic improvised version is a rusty razor blade and a pencil lead ("cat's whisker") — the point contact on the blade's oxide acts as a diode. It pulls the audio out of the radio wave.

Feed the output to a high-impedance earpiece (a piezo/crystal earpiece — worth stocking; ordinary earbuds are too low-impedance to work well). Connect: antenna → coil → diode → earpiece → ground. Adjust the coil tap until a station comes through.

For two-way comms and broadcasting, see Ham Radio; for protecting electronics from EMP, Faraday Storage.