HF radio

Space weather impacts radio communication in a number of ways. At frequencies in the 1 to 30 mega Hertz range (known as “High Frequency” or HF radio), the changes in ionospheric density and structure modify the transmission path and even block transmission of HF radio signals completely.

But the real advantage of HF is skywave propagation, where a single link can span distances as great as 3,000 km (a little less than 1,900 miles) . Skywave propagation occurs when the radio wave is refracted (bent) in the uppermost layer of the atmosphere, called the ionosphere.

The HF system on an aircraft provides two-way voice communication with or digitally coded signals for ground stations or other aircraft . The HF radio control panel is located where it is easily accessible to the pilot or copilot.

VHF operates at a higher frequency range than HF , usually between 30-300 MHz. These transmissions, due to their higher frequency, penetrate through the Ionosphere, with little or no refraction. VHF propagation is ‘line of sight’ in nature and so is restricted to shorter-range communications.

The advantage of the HF band is that radio waves of these frequencies are refracted (bent) by the ionosphere so that the waves return to the Earth’s surface at long distances beyond the horizon ,…

HF- Communication. High frequency (HF) is the ITU-designated range of radio frequency electromagnetic waves (radio waves) between 3 and 30 MHz . It is also known as the decameter band or decameter wave as the wavelengths range from one to ten decameters (ten to one hundred metres).