Amateur radio is the use of the radio spectrums to transmit and recieve signals. The radio spectrum is the medium through which radio signals travels. However, the radio spectrum changes based on the time of day and the condition of an atmosphere.
Therefore, individuals must have an understanding of the different behaviors of radio frequency in order to select the appropriate frequency for there communication goal. A frequency range chart can help an individual understands the different aspects of the radio spectrum. Furthermore, a frequency range chart can show an individual the different radio frequency bands available to them based off their license level.
How Radio Bands, Licenses, and Antennas Work
A Technician license allow individuals to use the VHF and an UHF bands. VHF and the UHF bands use a technology that allow the signals to travel in a straight line from the antenna to the receiver of the other individual’s signal. These signal do not bend around the horizon.
Therefore, if an individual select these frequency bands, they would need to ensure that the antenna is high enough to allow the signal to travel for significant distance. Additionally, many individuals uses repeaters to communicate on these frequency bands. Repeaters are devices located on high ground that extend the signal of the amateur radio operator’s radio signal over a significant areas.
Furthermore, the General class and Extra class license allows individuals to utilize the HF bands. High frequency bands use a process called “skip.” Skip is a process where high frequency radio signals bounces off the ionosphere of the atmosphere. The ionosphere reflects the high frequency radio signals, allowing the radio signal to reach an individual that is hundreds or even thousands of miles away.
Because the ionosphere change, the HF bands change their behavior based on the time of day. For example, individuals use the 40-meter band for local communication during the day, but during the night the same frequency band are used for intercontinental communication. Additionally, there are other frequency bands such as the WARC bands or the 6-meter band.
The ITU created the WARC bands to allow for less interference between radio signals. Therefore, these bands allow individuals to have more consistant conversations with other individuals who also select these frequency bands. The 6-meter band is another frequency band.
However, it is less predictable than the other bands. The 6-meter band can be inactive for long periods before it become active and allows communication with other amateur radio operators who use this frequency band. Furthermore, amateur radio operators must follow the rules establish by the International Telecommunication Union, or ITU.
The ITU divide the world into different regions. Therefore, a frequency that is legal to use in one part of the world may not be legal to use in another part of the world. Therefore, operators must visit the ITU website and ensure that the frequency they would like to use is legal in their region of the world.
Furthermore, the physics of the radio spectrum will determine the size of the equipment that an amateur radio enthusiast must use. The frequency of a radio signal is inversely related to the wavelength of that signal. Therefore, if the frequency increase, the wavelength of that signal will decrease.
Because high frequencies have small wavelengths, high frequencies uses small antennas to capture the signal. In contrast, low frequencies use large antennas with large wavelength. For example, the VHF frequency bands use an antenna that is small enough to fit on a car.
However, low frequencies require a large amount of space in an backyard to place the antenna so other amateur radio operators can receive the signals. Many amateurs uses a wire dipole antenna to begin communicating on the radio spectrum. A wire dipole antenna is a relatively simple tool that allows individuals to learn how to use the radio spectrum.
Additionally, individuals must monitor the solar flux reports to determine the best time to use their antenna in order to maintain an adequate connection with other amateur radio operators. This is because the radio spectrum and radio waves is continuously changing.
