Following this excellent post, doesn't it mean that if all your neighbours are using 5GHz band, your wifi network will face interference just like the case with 2.4GHz?
For 2.4GHz band, 1,6 and 11 are the recommended channels and are safe to use. Isn't this applied to 5GHz also?
According to physics, high frequency waves overlap each other lesser than low frequency and therefore produce less noise. But waves with similar frequency produce interference independent of their magnitude. It means that even 5GHz band will suffer just like 2.4GHz does.
Another noticeable thing is, in networking we use band and not a particular frequency but even in the case of band your waves is going to be collapsed with your neighbour.
Today, people use dual band wifi routers so in this case overlapping will be much higher than individual bands. Do channels 1, 6 and 11 work in this case?
Best Answer
No. In the 2.5 GHz band, the channel spacing is 5 MHz. That's why you can only use 1,6, and 11.
In the 5 GHz band, the channels are spaced farther apart - 20MHz, so you can use adjacent channels.
Note that under new FCC rules (in the U.S., of course), some channels are designated for wider bandwidth, to accommodate 802.11n and 802.11ac. In that case, there are fewer channels available.
A dual band router just means it has radios that operate in both the 2.5 GHz and 5 GHz band, Some can do either/or, while others can use both radios at the same time (meaning it can have clients on either band). This doesn't affect the channel spacing requirements.