Frequency range for High Frequency (HF) in aviation is which of the following?

Frequency range for High Frequency (HF) in aviation is which of the following?

• A. 3-30 MHz
• B. 30-300 MHz
• C. 0.3-3 MHz
• D. 300-3000 MHz

Answer: (A)

High Frequency in aviation spans from 3 to 30 MHz. Signals in this range can reflect off the ionosphere, allowing radio communication beyond the horizon, which is essential for long-range flights over oceans and remote areas. That ionospheric propagation is why HF is used for oceanic and remote-area communications, often with SSB voice to maximize efficiency. The other ranges are different bands: 30-300 MHz is the VHF band used mainly for line-of-sight air-to-ground and some air-to-air comms; 0.3-3 MHz is the LF/MF range and does not provide the same practical long-range air communications; 300-3000 MHz is the UHF band used for line-of-sight and radar-type systems.

High Frequency in aviation spans from 3 to 30 MHz. Signals in this range can reflect off the ionosphere, allowing radio communication beyond the horizon, which is essential for long-range flights over oceans and remote areas. That ionospheric propagation is why HF is used for oceanic and remote-area communications, often with SSB voice to maximize efficiency. The other ranges are different bands: 30-300 MHz is the VHF band used mainly for line-of-sight air-to-ground and some air-to-air comms; 0.3-3 MHz is the LF/MF range and does not provide the same practical long-range air communications; 300-3000 MHz is the UHF band used for line-of-sight and radar-type systems.