UHF
Understanding UHF
UHF is the most commercially important frequency range, hosting the majority of consumer wireless services. The propagation characteristics at UHF, including moderate building penetration, practical antenna sizes, and useful bandwidth, make it ideal for mobile and personal communications.
UHF Allocations
- TV broadcasting: 470-806 MHz (channels 14-69). Some spectrum reallocated to cellular.
- Cellular: 700 MHz, 850 MHz, 900 MHz, 1800 MHz, 1900 MHz, 2100 MHz, 2600 MHz bands.
- GNSS: GPS L1 (1575 MHz), L2 (1228 MHz), Galileo, GLONASS.
- Wi-Fi: 2.4 GHz ISM band.
- Military: SINCGARS (225-400 MHz), Link 16 (960-1215 MHz).
Wavelength: 1 m - 10 cm
Half-wave dipole at 900 MHz: 16.7 cm
Half-wave dipole at 2.4 GHz: 6.25 cm
Typical UHF propagation:
Building penetration: 10-20 dB
Urban path loss: 100-140 dB (1 km)
Frequently Asked Questions
What is UHF?
UHF covers 300 MHz to 3 GHz. It is the dominant frequency range for consumer wireless: cellular, Wi-Fi, GPS, Bluetooth, TV broadcasting, and RFID. UHF wavelengths (10 cm to 1 m) enable practical antenna sizes for mobile devices.
Why is UHF used for cellular?
UHF frequencies provide the best balance of coverage (good propagation and building penetration), capacity (sufficient bandwidth), and antenna size (practical for phones). Lower frequencies propagate better but have less bandwidth; higher frequencies have more bandwidth but worse penetration.
What is the difference between VHF and UHF?
VHF (30-300 MHz) has longer wavelengths, better diffraction around obstacles, and fewer available channels. UHF (300 MHz-3 GHz) has shorter wavelengths, more spectrum, and supports more data. Most modern wireless services have migrated from VHF to UHF.