What is WiFi Frequency, and what do you need to know about it?

Wireless/WiFi Frequency Bands

Wireless frequency bands are a set of radio waves that are used in WiFi networks. The 802.11 wireless standards designated both the 2.4 GHz and 5 GHz range for use in our WiFi networks. They also assigned 900 Mhz, 3.6 GHz, 4.9 GHz, 5.9 GHz, and 60 GHz frequency bands to wireless communications however currently WiFi primarily uses only 2.4 GHz and 5 GHz.

The International Telecommunication Union (ITU) is a UN agency named specific bands of RF spectrum as Industrial, scientific and medical radio bands (ISM). In the beginning, telecommunication was not the purpose because the idea was to reserve ISM as an international standard of frequencies for scientific, medical and industrial equipment.

Different countries and regions have different regulations regarding radio power settings and frequencies. According to the US regulatory domain, there are twelve ISM bands in which most users are 2.4GHz and 5GHz.

WiFi frequency bands Working

Wireless frequency bands are based on two-way radio communication to upload and download data.

Wireless devices such as cell phones, laptops, etc. have wireless adapters in them that communicate with wireless routers. These wireless adapters convert data into radio signals that are compatible with the wireless router or wireless access point that is being used. Once the devices convert the data into radio waves they are sent out over antenna and transmitted through the air to the wireless router/WAP.

The router then decodes the radio waves and turns them back into data which is then it is sent out over the network. The process is then reversed when the router receives data from the network and then transmits it to the wireless adapter.

Do WiFi signals go through objects?

Unfortunately, the path between the WiFi router and your device will probably have some kind of obstacle or obstruction in-between like furniture or walls, etc..

The cool thing about WiFi signal waves is that they either penetrate or bounce off of most materials. Obviously this depends on the types of materials and the strength of the signal coming from the wireless router. Metal, brick, concrete, solid wood and other very dense materials can block WiFi signals. But, inside of most buildings, the radio waves either penetrate through or bounce off of obstacles before they reach their destination.

Think of the WiFi signals like sound waves. You might be able to hear certain sounds like music or voices coming from different rooms of your house. This is because the sound waves can usually go through, or bounce off of the walls and furniture etc..

Just like the sound waves, WiFi signals can also bounce off of a lot of objects. This means that even though you might have obstacles in-between you and the router, the radio waves should still reach your device. (This does depend on the wireless router that you are using and where it is placed. To understand more about wireless routers check out my article explaining more about them)

The Law of Frequency related to Radio Waves:

Lower the frequency = less data throughput but further coverage area, with better ability to penetrate into solid materials.

Higher the frequency = more data throughput but less coverage area, with lesser ability to penetrate into solid materials.

An everyday example of this is sound waves. Have you ever pulled up next to a car with a loud car stereo and the windows rolled up? If so, you will notice that the bass/low frequencies are easily heard but you will not be able to hear the higher frequencies/voices and instruments as clearly. That is simply because the lower frequencies travel further than the higher frequencies.

Another example, the military uses a very specialized radio system with extremely low frequency (ELF) in order to communicate with the submarines far out in the ocean. The radio waves used for this type of communication need to be very low frequency in order to penetrate the water and reach the submarines.

What is WiFi Frequency, 2.4 GHz and 5 GHz

2.4 GHz WiFi frequency band

The 2.4 GHz wireless frequency band is an unlicensed frequency range from 2.4 to 2.4835 GHz. Since it is un-licensed, it is used by different applications such as WiFi, Bluetooth, microwave ovens, baby monitors, and remote controls, etc..

2.4GHz channels

Different frequency bands offer a different number of channels. In the US, 2.4GHz has 14 different channels that are 5MHz apart from each other. Of these 14 channels, only 3 are non-overlapping channels. These non-overlapping channels are 1, 6, and 11. These channels are used because there is no overlap from adjacent WiFi channels. This is important because it reduces the amount of interference that your WiFi will experience. Most routers today have an admin panel/menu that allows the user to login and change the settings. Inside the panel, you can update things like the WiFi frequency channels used and the WiFi password. Need some help on how to do this? check out my article about How to change your WiFi password here.

As the majority of people use the 2.4GHz band, it has become extremely overcrowded. This causes a slow speed of data transmission.

The 2.4GHz frequency band is used worldwide for wireless data transmission. However, the 5GHz frequency band is becoming very popular during recent years. As you will see below, it has some benefits over 2.4 GHz.

5GHz WiFi frequency band  

FCC introduced the 5 GHz ISM band (5.725-7.825GHz) from Unlicensed National Information Infrastructure (UNII) to advance the wireless technology. As discussed earlier higher frequencies have a shorter wavelength and a lesser ability to penetrate through obstacles.

In January 2014, the 802.11ac standard was introduced boasting double data transmission rates compared with old standards. With the new WiFi 5/802.11ac, the 5 GHz bands support high speeds up to 1300 Mbps.

The 5 GHz channels have no overlap with each other so all of the channels are useable. Unlike 2.4 GHz, 5 GHz is far less crowded and it has very low interference. This is a huge advantage of using 5 GHz compared to 2.4 GHz.

There are also some disadvantages of using 5 GHz such as very short wavelengths. The 5GHz WiFi frequency band covers a much smaller area than 2.4 GHz can. In fact, tests show that 5 GHz only covers about 1/3 to 1/2 the area compared to the 2.4 GHz.

Another difference between the Wireless Frequency bands is the potential cost of a 5 GHz network. The cost of having a complete 5 GHz network is about 2.5 times greater than the 2.4 GHz network. The reason for this is due to the added expense of more access points, cabling, and maintenance.

5 GHz channels

Similar to the 2.4GHz, 5Ghz is also divided into 5MHz channels. Without overlapping problems, every fourth channel (36,40,44,…..) is used which offers 20MHz channel. 

Altogether,  5 GHz consists of 45 WiFi channels. In the US, only the four lowest channels are available. The 802.11n standard is based on the concept of combining channels. When two 20 Mhz channels are combined it provides double the bandwidth with no need for isolation gap between them.

This technique is extremely useful and now most wireless routers have 40 MHz as a default bandwidth option.