Radio Frequencies

📡 Reference guide

Radio-frequency band names are convenient shorthand, but several naming systems coexist. UHF, L band, C band or NATO C band do not necessarily describe the same frequency interval.

The tables below compare the principal ITU, ISM, IEEE radar and NATO / EU / US ECM designations, together with representative uses.

Quick Reference

System	Coverage	Primary purpose
ITU band numbers and names	3 Hz–3 THz	General telecommunications nomenclature
ITU ISM designations	Discrete bands from 6.78 MHz to 245 GHz	Industrial, scientific and medical applications
IEEE radar letter bands	3 MHz–300 GHz	Radar engineering and related microwave usage
NATO / EU / US ECM bands	0–100 GHz	Military electronic-warfare spectrum designation

Important: a band name describes a frequency range, not a licence or an allocation. Always check the current national frequency plan, permitted power, duty cycle, channel plan and equipment requirements before transmitting.

ITU Radio-Frequency Band Nomenclature

The ITU system divides the spectrum into decades. In the formal ITU notation, the lower limit is excluded and the upper limit is included.

No.	Symbol	English name	Frequency range	Approx. wavelength	Typical uses
1	ELF	Extremely Low Frequency	3–30 Hz	100,000–10,000 km	Geophysics, extremely low-rate through-water communication
2	SLF	Super Low Frequency	30–300 Hz	10,000–1,000 km	Submarine communication, geophysical studies
3	ULF	Ultra Low Frequency	300 Hz–3 kHz	1,000–100 km	Through-earth links, mine communication, geophysics
4	VLF	Very Low Frequency	3–30 kHz	100–10 km	Time signals, navigation, submarine communication
5	LF	Low Frequency	30–300 kHz	10–1 km	Long-wave broadcasting, beacons, low-frequency RFID
6	MF	Medium Frequency	300 kHz–3 MHz	1 km–100 m	AM broadcasting, maritime and aeronautical services
7	HF	High Frequency	3–30 MHz	100–10 m	Short-wave broadcasting, amateur radio, long-range skywave links
8	VHF	Very High Frequency	30–300 MHz	10–1 m	FM radio, television, airband, marine and land-mobile radio
9	UHF	Ultra High Frequency	300 MHz–3 GHz	1 m–100 mm	Television, cellular, GNSS, 2.4 GHz Wi-Fi/Bluetooth, radar
10	SHF	Super High Frequency	3–30 GHz	100–10 mm	Microwave links, satellite communication, radar, 5/6 GHz Wi-Fi
11	EHF	Extremely High Frequency	30–300 GHz	10–1 mm	Millimetre-wave radar, high-capacity links, remote sensing
12	THF	Tremendously High Frequency	300 GHz–3 THz	1 mm–100 µm	Terahertz imaging, spectroscopy and research

Uses are representative only: formal allocations depend on the ITU Region and national regulations.

ITU ISM Bands

ISM means industrial, scientific and medical. Radio systems such as RFID, Wi-Fi, Bluetooth, Zigbee or LoRa commonly share some of these ranges under separate radio-device rules; they are not themselves automatically classified as ISM equipment.

Frequency range	Centre frequency	ITU scope	Common ISM or shared-radio examples
6.765–6.795 MHz	6.780 MHz	Worldwide; special authorization	Induction heating, plasma and industrial processing
13.553–13.567 MHz	13.560 MHz	Worldwide	RFID, NFC, induction heating
26.957–27.283 MHz	27.120 MHz	Worldwide	Industrial heating, diathermy, short-range devices where permitted
40.66–40.70 MHz	40.68 MHz	Worldwide	Industrial heating, telemetry and short-range devices where permitted
433.05–434.79 MHz	433.92 MHz	ITU Region 1, with country exceptions; special authorization	Short-range sensors, remote controls, telemetry
902–928 MHz	915 MHz	ITU Region 2	UHF RFID, LoRa/LPWAN, telemetry
2.400–2.500 GHz	2.450 GHz	Worldwide	Microwave heating, Wi-Fi, Bluetooth, IEEE 802.15.4
5.725–5.875 GHz	5.800 GHz	Worldwide	Industrial heating, RFID, short-range and WLAN systems where permitted
24.00–24.25 GHz	24.125 GHz	Worldwide	Motion, presence, level and short-range radar sensors
61.0–61.5 GHz	61.25 GHz	Worldwide; special authorization	Millimetre-wave sensing and short-range links
122–123 GHz	122.5 GHz	Worldwide; special authorization	High-resolution sensing, spectroscopy
244–246 GHz	245 GHz	Worldwide; special authorization	Imaging, spectroscopy and scientific research

Under ITU Radio Regulations Nos. 5.138 and 5.150, the regional conditions differ. Radiocommunication services operating in the No. 5.150 bands must accept harmful interference from ISM applications. National licence-exempt ranges can be narrower than the ITU designation; for example, European 433 MHz and 868 MHz SRD rules must not be inferred from this table.

IEEE Radar-Frequency Bands

The IEEE 521 family standardizes letter designations used in radar engineering. The same letters are also used informally for satellite and microwave systems, sometimes with different limits.

Band	Frequency range	Approx. wavelength	Typical radar and microwave uses
HF	3–30 MHz	100–10 m	Over-the-horizon radar, ionospheric sensing
VHF	30–300 MHz	10–1 m	Long-range surveillance, foliage-penetration research
UHF	300 MHz–1 GHz	1 m–30 cm	Early warning, space surveillance, long-range detection
L	1–2 GHz	30–15 cm	Air surveillance, tracking, long-range radar
S	2–4 GHz	15–7.5 cm	Weather, marine and air-traffic-control radar
C	4–8 GHz	7.5–3.75 cm	Weather radar, tracking, satellite and microwave links
X	8–12 GHz	3.75–2.5 cm	Marine radar, imaging, mapping and fire control
Ku	12–18 GHz	2.5–1.67 cm	High-resolution radar, satellite links, speed measurement
K	18–27 GHz	1.67–1.11 cm	Short-range radar and sensing; atmospheric absorption near 22 GHz
Ka	27–40 GHz	11.1–7.5 mm	High-resolution radar, satellite broadband, altimetry
V	40–75 GHz	7.5–4 mm	Short-range links, research radar, strong absorption near 60 GHz
W	75–110 GHz	4–2.73 mm	Automotive radar, security imaging, remote sensing
mm	110–300 GHz	2.73–1 mm	Millimetre-wave imaging, spectroscopy and experimental radar

Do not mix designation systems: IEEE C band is 4–8 GHz, while NATO/ECM C band is 500 MHz–1 GHz.

NATO / EU / US ECM Frequency Designations

These letter bands are used in military electronic warfare and spectrum-management contexts. They deliberately differ from IEEE radar bands.

Band	Frequency range	Broad spectrum area	Representative context
A	0–250 MHz	ELF through most of VHF	HF/VHF communications, navigation and surveillance
B	250–500 MHz	Upper VHF / lower UHF	Tactical communication and surveillance
C	500 MHz–1 GHz	UHF	Communication, telemetry and long-range radar
D	1–2 GHz	UHF / IEEE L	Surveillance, navigation and satellite links
E	2–3 GHz	UHF / IEEE S	Radar, telemetry and communication
F	3–4 GHz	SHF / IEEE S	Air and weather surveillance radar
G	4–6 GHz	SHF / IEEE C	Radar, microwave and satellite links
H	6–8 GHz	SHF / IEEE C	Tracking radar and fixed/satellite links
I	8–10 GHz	SHF / IEEE X	Imaging, tracking and fire-control radar
J	10–20 GHz	SHF / IEEE X, Ku and K	High-resolution radar and satellite links
K	20–40 GHz	SHF/EHF / IEEE K and Ka	Precision radar, seekers and high-capacity links
L	40–60 GHz	EHF / IEEE V	Millimetre-wave sensing and short-range links
M	60–100 GHz	EHF / IEEE V and W	Millimetre-wave radar, imaging and electronic support

How to Read an RF Band Name

Identify the naming system. “L band” generally suggests IEEE radar/microwave usage, while “NATO L band” means 40–60 GHz.
State numerical limits. For specifications and compliance work, write the actual range in MHz or GHz.
Check the region. ITU Regions 1, 2 and 3 do not share every allocation or ISM designation.
Check local rules. Allocation, licence exemption, EIRP, bandwidth, duty cycle, indoor/outdoor use and equipment conformity are separate questions.

The free-space relationship between frequency and wavelength is:

λ = c / f

Where λ is wavelength, f is frequency and c ≈ 299,792,458 m/s. Use the wavelength calculator for exact conversions.