Tamara Wilhite is a technical writer, industrial engineer, mother of two, and published sci-fi and horror author.
VHF and UHF systems are not mutually exclusive. Dual VHF/UHF wireless systems are used in television broadcasts, amateur radio and data transmissions.
Very High Frequency (VHF) and Ultra-High Frequency (UHF) wireless systems can be used at the same time with the same equipment if proper technical precautions are taken in advance. Without these steps, UHF and VHF signals can interfere with each other.
What are VHF and UHF Wireless Systems?
VHF and UHF wireless systems are sending data simultaneously in the white space, the frequency ranges once used by TV channels to send data. Dual VHF/UHF wireless systems are used in television broadcasts, amateur radio and data transmissions. Very High Frequency (VHF) and Ultra-High Frequency (UHF) wireless systems can be used at the same time with the same equipment if proper technical precautions are taken in advance.
How to Use VHF and UHF Antennas Simultaneously
Moving the UHF and VHF radio antennas farther apart will prevent them from interfering with each other. Moving one receiver to the next room or putting distance between the antennas will reduce interference. This is why many ham radio operators have a "ham shack", a separate room for their amateur radio equipment so that it doesn't interfere with nearby televisions, wireless phones or other wireless devices.
Directional antennas pointed in opposite directions will reduce interference between nearby UHF and VHF systems, even from sources like radio transmitters. Buying radios and wireless systems with high quality radio frequency (RF) filters also reduces interference. However, cable shielding makes little difference in the signal reception. Cable shielding will marginally reduce electromagnetic interference.
You can also reduce interference by using a duplexer or diplexer to process the signal received by the antenna. Duplexers process the signal received from the antenna and uses radio frequency filters to filter out noise. A diplexer also contains RF filters, but its filtering is much broader than a duplexer. In the old days, the TV had separate VHF and UHF tuners to receive the audio and picture signals.
A diplexer would send the VHF signals to the VHF tuner, and the UHF signals to the UHF tuner. In essence, the TV used a dual VHF and UHF antenna but uses separate receivers for each type of signal. The diplexer is almost like a rock crusher, sending the little rocks or little radio waves go over here, and the big rocks, or longer radio waves go over there. The diplexer sorts out the signals and performs the filtering, preventing interference between VHF and UHF signals.
If interference from a major source is an ongoing problem, VHF antennas are a better choice for the application, since signal interference does not travel as far on these frequencies. However, UHF antennas benefit from less interference from wireless devices like security systems, cell phones and electrical equipment.
A low-tech solution for this problem is to use wired connections. For example, if interference is bad, use a conventional phone instead of a wireless phone.