High Frequency (HF)
Shortwave broadcasting · Amateur radio · Aviation HF comms
| Frequency Range | 3–30 MHz |
| Wavelength | 10–100 m |
| ITU / Standard | ITU Band 7 |
Applications
- →Shortwave broadcasting
- →Amateur radio
- →Aviation HF comms
- →Over-the-horizon radar
- →RFID (13.56 MHz)
Propagation Characteristics
Ionospheric skip enables long-distance propagation. NVIS (Near Vertical Incidence Skywave) used for regional comms. Skip distance varies with solar activity and time of day.
Regulatory Notes
Licensed use in most regions. 13.56 MHz is a global ISM frequency. Amateur allocations at 3.5, 7, 10, 14, 18, 21, 24, 28 MHz.
Related Calculators
Wavelength / Frequency
Convert between frequency, wavelength, and wavenumber in free space or any dielectric. Calculate half-wave and quarter-wave lengths for antenna design. Free, instant results.
Free-Space Path Loss
Calculate free-space path loss (FSPL) in dB using the Friis equation. Enter frequency and distance for wireless link budget analysis. Free, instant results.
Dipole Antenna
Calculate dipole antenna length for any frequency — enter MHz, get half-wave and quarter-wave dimensions in mm. Includes gain (2.15 dBi), radiation resistance (73 Ω), and 50 Ω VSWR. Supports velocity factor for insulated wire.