Have you ever wondered how exactly a radio wave goes through the air and reaches another station? A radio wave is similar to a wave in the ocean. The important similarities are that they both have frequency and wavelength.
The wavelength of a wave would be calculated by determining the distance between the peak of one wave and the peak of the next wave. The frequency of the wave is determined by taking the velocity of the wave and dividing it by the wavelength.
A radio wave is part of the electromagnetic spectrum. Instead of water moving in a wavelike manner, what’s moving through the air is a wave of energy. These waves move at the speed of light and contain both electric and magnetic fields.
To calculate the frequency of a radio wave, you would just divide the speed of light by the wavelength. The relationship between wavelength and frequency is the longer the wavelength, the lower the frequency. If the peak of a wave in the ocean is far away from the peak of the next wave, then the frequency of someone getting hit with a wave in the water becomes less.
Now that we are familiar with frequency, we can talk about the different bands for amateur radio operators. For HAMs, there are different frequencies that we are and are not allowed to use because certain frequencies require different licenses. There are also different frequencies which serve to transmit different kinds of data.
When you hear other HAMs talking about a 2m band or a 6m band, they are referring to a band of frequencies whose wavelength is about 2m or 6m. For example, the VHF band (very high frequency band) ranges from about 50MHz to 225MHz and ecompasses 6m, 2m and 1.25m. That’s because the speed of light divided by 6 would result in a number between 50,000,000 and 54,000,000.
The UHF (ultra high frequency) bands range from 420 MHz to 1240 MHz and are mostly used for RTTY, data, phone and image transfer. Any licensed HAM operator can talk on these frequencies. They are the highest radio frequencies which means they have the shortest wavelengths ranging from 70cm to 23cm.
The VHF (very high frequency) bands range from 50 MHz to 220 MHz. The UHF/VHF bands are the bands that beginner radio operators will start out on. With a technician license, you can talk on all of the bands in these ranges but not on many most in the HF ranges.
The HF (high frequency) bands range from 3.5 MHz to 28 MHz and support RTTY, data, image, phone and SSB. Most high frequency bands require operators to at least have a General license. High frequency bands require larger antennas and more power to transmit.
The LF (low frequency) bands range from 135 kHz to 1.8 MHz and facilitate RTTY, data, phone and image. The wavelengths of the low frequencies range from 2200 meters to 160 meters – that’s a pretty big wave!
Not all frequencies act the same in the air. Higher frequencies tend to not go as far as lower frequencies because there is more energy lost to the medium as it travels. Because of this, new HAMs might need to use repeaters.
HF communications actually rely sometimes on what’s called skywave transmission. High frequency radio waves can actually be bounced off of the Earth’s ionosphere where UHF and VHF get absorbed. This allows you to talk to people beyond the horizon at specific times of the day.
Repeaters are found everywhere usually on top of tall hills or buildings. They are stations dedicated to picking up signals on one frequency and transmitting them out on another frequency. This enables operators working on UHF and VHF ranges to talk to people who are a little bit out of their reach.
Radio waves are just waves made out of energy instead of water that travel through the air. All radio waves have wavelengths and frequencies and the way you calculate the frequencies is to divide the speed of light by the wavelength. The higher the frequency, the lower the wavelength.
There are different frequency bands you can use to transmit different kinds of information. Be sure that you familiarize yourself with the different bands and what they are used for so you can be sure to be on the right channel. There are tons of great frequency charts to print out and keep in your HAM shack.
Every state has tons of repeaters to access. They are a great way for beginners with UHF/VHF radios to talk to people a little bit farther away. Repeater frequencies are super easy to find and use.
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