Radio propagation by band
Range by frequency band:
| Band | Propagation | Range |
|---|---|---|
| LF / MF | Ground wave by day, following the curvature of the Earth | Steady by day; at night skywave adds range |
| HF | Skywave off the ionosphere | Very long |
| VHF / UHF | Line of sight only | Grows with altitude; terrain blocks it (TC AIM COM 4.5(b), COM 4.7) |
Trap: expecting a VOR to reach as far as an NDB at low altitude. VHF is line of sight; terrain and the horizon cut it off.
References
- FAA-H-8083-15 IFH ch.9, Basic Radio Principles (ground wave, sky wave)
- FAA-H-8083-25 PHAK ch.16, ADF (LF/MF signals follow the curvature of the Earth)
- TC AIM COM 4.5(b), VOR range and line-of-sight
- TC AIM COM 4.7, DME line-of-sight reception