RF Bands & UsageModule 4

Covers ITU Radio Regulations and the RF frequency spectrum — from VLF submarine communications to EHF millimetre wave. Includes an interactive spectrum explorer, satellite band reference, and ITU region overview. Depends on Module 3 (propagation context).

4.4

Standards Organisations

Radio frequency spectrum is a finite shared resource. Without coordination, transmitters from different countries and services would interfere with one another. A hierarchy of international and regional standards organisations allocates spectrum, defines technical constraints, and resolves disputes.

Compliance with ITU Radio Regulations is mandatory under international treaty law and is incorporated into national licensing frameworks. Regional bodies such as CEPT (Europe), FCC (USA), and OFCOM (UK) implement these allocations domestically and may impose additional technical parameters.

The ITU sits at the top of the spectrum-management hierarchy. Its Radio Regulations have treaty status, binding all 193 member states.

4.4.1

International Telecommunications Union (ITU)

The International Telecommunications Union (ITU) is a United Nations specialised agency founded in 1865, making it one of the oldest intergovernmental organisations in the world. Its mandate covers all forms of telecommunications, including radio, telephone, and internet infrastructure.

The ITU is organised into three sectors, each producing distinct outputs: ITU-R produces Recommendations (RR, ITU-R Reports) and administers the Radio Regulations; ITU-T produces technical standards for network interoperability; ITU-D focuses on bridging the digital divide in developing nations.

ITU-R: Radiocommunication Sector — manages spectrum and satellite orbit resources, publishes Radio Regulations and ITU-R Recommendations (e.g. ITU-R M.1457 for IMT standards).
ITU-T: Telecommunication Standardisation Sector — produces international standards (ITU-T Recommendations) covering protocols, codecs, and network architecture (e.g. H.264, G.711).
ITU-D: Telecommunication Development Sector — facilitates equitable and sustainable development of telecommunications and ICT in developing countries through technical assistance and capacity building.

ITU-R is the sector most relevant to RF engineering. It convenes the World Radiocommunication Conference (WRC) every three to four years to update the Radio Regulations.

4.4.2

ITU Radio Regulations

The ITU Radio Regulations (RR) form an international treaty governing the use of radio frequency spectrum and satellite orbits. They define which frequency bands are allocated to which radiocommunication services and under what conditions those services may operate.

Article 5 of the Radio Regulations contains the international Table of Frequency Allocations — a master table spanning 9 kHz to 3 000 GHz. Each band entry lists one or more service allocations (e.g. Fixed, Mobile, Broadcasting) and whether each allocation is Primary, Secondary, or governed by a Footnote.

Primary Allocation: A service allocated to a band on a primary basis. Stations of a primary service shall not cause harmful interference to, and cannot claim protection from, stations of other primary services in the same band.
Secondary Allocation: A service allocated to a band on a secondary basis. Secondary stations must not cause harmful interference to primary stations and cannot claim protection from them.
Footnote Allocation: Additional conditions or exceptions applied to specific administrations or regions within a band, referenced by number (e.g. 5.340). Footnotes can grant or restrict use beyond the main table entry.
ITU Region: The world is divided into three ITU regions. Region 1: Europe, Africa, and the Middle East. Region 2: The Americas. Region 3: Asia-Pacific. Allocations can differ between regions.

A secondary service must accept interference from all primary services and may not raise objections. This hierarchy is critical when designing systems that share spectrum with incumbent services.

4.5.1

Introduction to RF Frequency Bands

The RF spectrum spans an enormous range — from roughly 3 kHz up to 300 GHz — a factor of 100 million in frequency. To make this manageable, engineers and regulators divide the spectrum into named bands, each covering a single decade (a ten-fold increase in frequency).

The ITU designates nine bands numbered 4 through 12 (Band N spans 0.3 × 10ⁿ Hz to 3 × 10ⁿ Hz). The designator letters — VLF, LF, MF, HF, VHF, UHF, SHF, EHF — are defined in Article 2 of the Radio Regulations and are universally used in spectrum management, licensing, and equipment classification.

Because of the logarithmic nature of the spectrum, each band has equal width on a log-frequency axis, even though higher bands span a far greater absolute bandwidth. For example, the UHF band (300 MHz–3 GHz) spans 2.7 GHz of absolute bandwidth, while the HF band (3–30 MHz) spans only 27 MHz — yet both cover one decade.

VLF (3–30 kHz): Very Low Frequency. Penetrates seawater; used for submarine communications. Extremely long wavelengths (10–100 km) require very large antennas.
LF (30–300 kHz): Low Frequency. Ground-wave propagation; used for AM broadcasting and navigation beacons (NDB, LORAN).
MF (300 kHz–3 MHz): Medium Frequency. AM broadcast band sits here (535–1705 kHz). Ground wave by day, sky wave at night.
HF (3–30 MHz): High Frequency. Ionospheric sky-wave propagation enables global communications without satellites. Amateur radio, shortwave broadcasting, aeronautical HF voice (SELCAL).
VHF (30–300 MHz): Very High Frequency. FM broadcast (88–108 MHz), air traffic control voice (118–136 MHz), analogue/digital TV.
UHF (300 MHz–3 GHz): Ultra High Frequency. Cellular (LTE/5G sub-6 GHz), Wi-Fi (2.4 GHz/5 GHz), GPS (1.176–1.575 GHz), digital TV, ISM bands.
SHF (3–30 GHz): Super High Frequency. Microwave links, satellite downlinks (Ku/Ka), radar, Wi-Fi 6 GHz, 5G mmWave lower range.
EHF (30–300 GHz): Extremely High Frequency (millimetre wave). 5G FR2 (24.25–52.6 GHz), 60 GHz Wi-Fi (802.11ad/ay), automotive radar (77 GHz), imaging systems.

Propagation mechanism changes dramatically across bands. As frequency increases: ground-wave range decreases, ionospheric reflection ceases above ~30 MHz, atmospheric absorption peaks (60 GHz O₂, 183 GHz H₂O), and free-space path loss increases as 20 log₁₀(f). Antenna size scales inversely with frequency (λ = c/f).

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