The pros and cons of WiFi frequencies 2.4GHz and 5GHz

Nowadays all WiFi access points (APs) or wireless network routers work on the 2.4GHz band of wireless frequency, while the newer dual-band devices also support the 5GHz band.

The WiFi standards that work on 2.4GHz band are:

• 802.11b (speed is up to 11Mbps)
• 802.11g (speed is up to 54Mbps)
• 802.11n (speed is up to 150Mbps for 20MHz channel width, 300Mbps for 40MHz channel width)

The WiFi standards that work on 5GHz band are:

• 802.11a (speed is up to 54Mbps)
• 802.11n (speed is up to 150Mbps for 20MHz channel width, 300Mbps for 40MHz channel width)
• 802.11ac (speed can reach 6.8Gbps with 8 antennas running at 160Mhz channel width)

For the dual-band WiFi AP or router, you can turn on either one of the frequency bands, or turn on both of them at the same time.

The pros / advantages of 2.4GHz band:

• Has a wider signal coverage area.
• Better penetration through walls and physical barriers.
• WiFi b/g/n supported by all wireless devices

The cons / disadvantages of 2.4GHz band:

• As most of the WiFi devices are using this band, it could be congested with a lot of interference if there are a lot of WiFi devices nearby.
• Out of its 13 available channels, only Channel 1, 6, 11 are not overlapping.
• Might get interference from microwave ovens, Bluetooth devices, wireless keyboard/mouse, cordless phones, etc. which are also operate on 2.4GHz frequency band.

The pros / advantages of 5GHz band:

• At the mean time, few WiFi devices are using this band, so it is less congested with much lesser interference.
• Has 23 non-overlapping available channels.
• Supports much higher network speed with 802.11ac standard.

The cons / disadvantages of 5GHz band:

• Has smaller signal coverage area.
• Poor penetration power through walls and physical barriers.
• Older wireless devices might not be able to work on this band.
• Might get interference from radar which also operates on 5GHz frequency band.

Below is the WiFi signals detected in a shopping mall. You can see how congested is the 2.4GHz band and how clear is the 5GHz band. Congestion and interference can cause wireless connection problems such as intermittent connection lost, slow speed, unable to establish connection with AP, etc.

I am sure you will get similar result at your office or in your residence when your neighbours are also using WiFi.

If you have mobile devices that can work on 5GHz band and you have a dual-band AP/router, you might probably want to turn on both of them to get the best of both worlds.