SURVIVAL SOLUTIONS — RADIO FREQUENCIES AND FIELD COMMUNICATION
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Understand HF, VHF and UHF bands, broadcast and distress services, antenna fundamentals, reception versus transmission permissions, and emergency-radio practice.

The band, antenna, geography, power and licence rules determine whether a radio can reach another person. Frequency charts are reference points, not permission to transmit.

SAFETY: Do not transmit on aviation, marine, rescue or other protected frequencies without authority and a genuine legal basis. Regulations and channel allocations vary by jurisdiction.

1. Identify the radio band
HF spans 3–30 MHz and can support long-range contacts when propagation cooperates. VHF spans 30–300 MHz and is often line of sight. UHF spans 300–3000 MHz and is commonly used for local handheld communication and data.

2. Know critical frequencies
121.5 MHz is an international civil aviation distress frequency; 156.8 MHz is marine VHF channel 16; registered 406 MHz distress beacons serve satellite alerting systems. These are safety channels, not places to test homemade equipment.

3. Recognize common non-emergency services
Broadcast FM radio occupies 87.5–108 MHz in many countries; marine AIS normally broadcasts on 161.975/162.025 MHz; ADS-B aircraft data often uses 1090 MHz. European PMR446 operates in the 446 MHz band with compliant equipment and applicable national rules.

4. Match antenna, distance and conditions
Antenna placement, polarization, terrain, atmospheric conditions and cable losses can dominate performance. Even a powerful transmitter cannot guarantee reception behind a mountain. Check batteries and line-of-sight paths before relying on equipment.

5. Separate receiving from transmitting
Receiving permissible public transmissions with a suitable receiver is distinct from transmitting. For two-way radios use certified equipment and appropriate licensing or licence-exempt allocations for the exact country. Amateur-radio privileges are not universal.

6. Prepare an emergency plan
Keep a battery-powered broadcast receiver and written contact schedule, call signs when legally assigned, emergency channels, family meeting points, backup charging and a shared message format. Do not block a distress frequency with routine traffic.

REFERENCES
- FAA ADS-B FAQ: https://www.faa.gov/air_traffic/technology/equipadsb/resources/faq
- ITU Radiocommunication Sector: https://www.itu.int/ITU-R/
- Ofcom PMR446 information: https://www.ofcom.org.uk/