UHF Vs. VHF
Very High Frequency and Ultra High Frequency are two neighboring radio-transmission frequency bands. The VHF and UHF bands offer advantages over each other when catering to different transmission use cases. Transmissions like FM radio, TV, amateur radio, aeronautical radio navigation, cellular phones and Wi-Fi fit within the VHF and UHF spectrums.
Radio Frequency Ranges
VHF and UHF both belong to the radio waves division of the electromagnetic spectrum, which includes visible light. UHF transmissions work on higher frequency levels than VHF transmissions. VHF comes in on the low-end in the 30 MHz to 300 MHz range, whereas UHF encompasses the 300 Mhz to 3 GHz range. The UHF range represents a much larger share of the electromagnetic spectrum than VHF.
Pros and Cons of Frequency
The lower the frequency, the larger the wave. Low-frequency signals travel farther and are less susceptible to object interference. Because VHF is lower frequency than UHF, VHF broadcasts can travel longer distances and are less likely to encounter interference. However, UHF has the advantage of having more bandwidth to work with in the range, which gives space for simultaneous transmissions, making it less susceptible to interference from other radio waves. Both VHF and UHF are too high in the frequency range to bounce off the ionosphere like AM radio transmissions in the High Frequency range, which limits how far the signal can go but prevents signals from interfering with one another.
Best Fit for VHF
VHF is an optimal solution for broadcasting. VHF's range limitation prevents interference from broadcasts hundreds of miles away. Additionally, VHF is better suited for broadcasting purposes because it is less prone to weather interference than UHF. VHF is good for broadcasting TV and radio: You don't have to worry about a TV or radio broadcast from Chicago overpowering one from Denver with VHF, and you're less concerned with interference than with UHF. Additionally, VHF works better for situations where equipment cost and energy consumption are concerns.
Best Fit for UHF
UHF is a better option than VHF when you have a large number of different short-range signals working in the same area. UHF is a better fit when you're worried that different transmitting devices are going to interfere with each other. The extra space gives devices more room to work with to avoid using the same frequencies, making UHF better suited for home electronics, mobile phones and two-way radios. Despite not being the optimal solution for TV broadcasts because the signal is harder to tune in, the UHF spectrum hosts TV signals.
References & Resources
- PC Magazine Encyclopedia: Definition of: VHF
- PC Magazine Encyclopedia: Definition of: UHF
- U.S. Dept. of Commerce: United States Frequency Allocations: The Radio Spectrum
- PC Magazine Encyclopedia: Definition of: Spectrum
- IT Outsourcing: Radio HF/VHF/UHF
- Audio-technica: UHF Versus VHF
- Indiana University: A Guide to UHF Television Reception