The Two Types Of Radio Communication Frequencies In Aircraft Antennas

Proper radio communication is a basic need of anyone piloting an aircraft. To ensure the reliability of its communication systems, aircraft are fitted with sophisticated radio equipment and antenna. Radio signals typically travel in one of two frequency bands, very high frequency (VHF) or ultra high frequency (UHF). Aircraft use VHF for short range communication, transmitting radio signals from 54 MHz and 216 MHz. The range of communication of a given frequency depends on the height of the antenna relative to the ground. This means that aircraft at high altitudes have a larger VHF ranges than those at lower altitude.

VHF range is imperative for radio communication, and is calculated thusly: 1.33 x (√H-Aircraft + √H-gs). Here H-aircraft represents the altitude of the aircraft and H-gs represents the height of the ground station antenna in contact with the aircraft. This equation will give you the optimum range in perfect conditions, but fails to account for atmospheric conditions as well as deficiencies in transmitter power, receiver sensitivity, and overall aircraft antenna performance. For a more accurate figure, substituting 1.2 into the beginning of the formula will provide better results.

UHF spans from 300 MHz to 3 GHz (equivalent to 3,000 MHz) and spreads by line of sight, meaning it is blocked by mountains, hills, and even large buildings. UHF antenna signals are sent on much shorter waves that arrive closer together. In these sense, the term ‘frequency’ is quite literal. UHF transmissions are not capable of traveling beyond the horizon, allowing for the reuse of frequency channels by other users in the same area. In the right conditions, UHF waves can travel beyond the line of sight. This is called due tropospheric propagation and it occurs when a traveling signal encounters a rise in temperature in the atmosphere.

Whether you’re communicating by UHF or VHF waves, having the right equipment is crucial. At ASAP Supply Chain, owned and operated by ASAP Semiconductor, we can help you find all the radio communication components as well as general parts for the aerospace, civil aviation, and defense industries. We’re always available and ready to help you find all the parts and equipment you need, 24/7-365. For a quick and competitive quote, email us at sales@asap-supplychain.com or call us at 1-702-919-1616.