HFkommunikasjon

HFkommunikasjon refers to radio communication using the high-frequency (HF) portion of the radio spectrum, typically 3 to 30 MHz. The term is used in Norwegian and other languages to describe long-distance wireless links that extend beyond line of sight. HFkommunikasjon encompasses services such as amateur radio, maritime and aviation communications, government networks, and shortwave broadcasting.

Propagation and principles: The key feature of HF is skywave propagation. Signals are directed upward, refracted by the ionosphere, and returned to Earth, enabling intercontinental reach. Propagation conditions depend on time of day, season, solar activity, and geomagnetic factors. The D-layer can absorb signals during the day, while the F-layer often supports long-range reflection at night.

Equipment and operation: HF communications require transceivers that cover roughly 3–30 MHz and appropriate antennas, such as long wires, dipoles, inverted-Vs, or verticals. Common modes include SSB, AM, and CW, with increasingly popular digital modes (e.g., RTTY, PSK31, FT8). Power levels range from portable operations in the watts to larger transmitters used by commercial or maritime services.

Regulation and use: HF bands are allocated by national authorities in coordination with international rules set by the ITU. Licensing, call signs, and operator requirements apply in many regions. HF remains important for emergency communications, remote or underserved areas, and international broadcasting and amateur networks, complementing satellite and internet-based links.