1.3 Frequency Band Allocation

Frequency bands are segments of the electromagnetic spectrum designated for specific types of communication services. Proper allocation and management of these bands are crucial for ensuring interference-free operation of various services.

Amateur Radio Frequency Bands

• Purpose: Amateur radio operators are granted access to specific frequency bands for non-commercial, experimental, and educational purposes. These bands enable amateurs to communicate, experiment with radio technologies, and engage in technical investigations.
• Allocation: The frequency bands allocated to amateur radio are specified in the Australian Radiofrequency Spectrum Plan. They include segments within HF (High Frequency), VHF (Very High Frequency), UHF (Ultra High Frequency), and even some SHF (Super High Frequency) ranges.
  • HF Bands: Typically used for long-distance communications via ionospheric propagation. Common HF bands for amateurs include 1.8 MHz, 3.5 MHz, 7 MHz, 14 MHz, 21 MHz, and 28 MHz.
  • VHF Bands: Primarily used for medium-range communication, including local and regional contacts. The 6-metre (50 MHz) and 2-metre (144 MHz) bands are popular among Australian amateurs.
  • UHF Bands: Suitable for shorter-range communications, often used for local contacts and repeater operations. The 70-centimetre (430 MHz) band is widely used.
  • SHF Bands: These higher frequencies are used for specialised activities, such as satellite communications and experimental work. Examples include the 23-centimetre (1.2 GHz) and 13-centimetre (2.4 GHz) bands.

Broadcasting Frequency Bands

• AM Broadcasting: Utilises medium frequencies (MF) typically in the range of 526.5 kHz to 1606.5 kHz. These bands allow AM radio stations to reach wide audiences, especially over long distances at night due to favourable propagation conditions.
• FM Broadcasting: Operates within the VHF band, specifically from 87.5 MHz to 108 MHz. FM radio provides high-fidelity sound quality and is less susceptible to interference compared to AM radio.
• Television Broadcasting: Uses VHF (174-230 MHz) and UHF (470-694 MHz) bands for transmitting TV signals. Digital television has largely replaced analogue signals, allowing for more efficient use of these frequencies and better picture quality.

Aeronautical Frequency Bands

• Purpose: Aeronautical communication bands are essential for air traffic control, navigation, and communication between pilots and ground stations.
• VHF Bands: The primary band for aeronautical communication is the VHF band, specifically from 108 MHz to 137 MHz. This range includes both voice communication and navigation aids (e.g., VOR and ILS systems).
• HF Bands: Long-distance aeronautical communications, especially over oceans and remote areas, utilise HF bands ranging from 2 MHz to 30 MHz. These frequencies enable long-range communication through skywave propagation.

Maritime Frequency Bands

• Purpose: Maritime communication bands are critical for ship-to-ship, ship-to-shore, and distress communications.
• MF/HF Bands: These bands (300 kHz to 30 MHz) are used for long-range communication and distress signals, including the Global Maritime Distress and Safety System (GMDSS) frequencies.
• VHF Bands: The maritime VHF band (156 MHz to 174 MHz) is used for short-range communication, including channels designated for distress (Channel 16 at 156.8 MHz), navigation, and operational purposes.

Summary:

Frequency band allocation ensures that various communication services can operate effectively without causing harmful interference to each other. Amateur radio operators have access to specific bands where they can experiment and communicate, contributing to the advancement of radiocommunications. Other services, such as broadcasting, aeronautical, and maritime, have designated bands tailored to their unique operational needs. Understanding the allocation and proper use of these frequency bands is essential for all radiocommunication users to maintain orderly and efficient spectrum use.