How to use 5 MHz Wi-Fi channels?

I mean responding with an avoidant response like "what for?" without seeing the possibilities of using 5 MHz. The justification for use comes later when one finds a situation in which it is better to use smaller bandwidths, such as when looking to have less overlapping interference.

I'm lost by your response - unless you're merely suggesting illegal bandwidths just because there's a use case described by someone. I"m aware of using 5 and 10 MHz bandwidths, but again - they require a license.

Nonetheless, good discussion.

Exactly. I suggest that channels on 5 MHz can be used and are not "illegal" or part of the standard. That is, give me to use only channels 1, 6 and 11 that do not overlap or give me the 11 channels but with a maximum of 5 MHz of bandwidth so that they do not overlap. Unless there is a technical reason not to use lower bandwidths like 5 MHz.

It seems as if you're asking for 5 and 10 MHz WiFi channels to be re-added to the International Standards and International Radio Regulations (and regulations of other countries) for 2.4 GHz?


Free to lobby for it. I personally don't recall the history of why it was removed.

Exact. I don't understand why they designed the standard with overlapping channels. It is like a frequency from an FM radio overlapping with the frequency of another radio. The funny thing is that in 5 GHz the 20 MHz channels do not overlap.

1 Like

On top of that, if you do a search like "why doesn't 2.4 GHz Wi-Fi use lower bandwidths?", you get results that have nothing to do with the question. It seems that no one asks that question for answers to appear.

LOL, who woulda imagined that people would want high speed (bandwidth) WiFi in the future when 802.11 was originally conceived in the 1980's?

Who would imagine people could afford it, have routers with open source software and have an OpenWrt community where you asked this question? :smiley:

Recall the original 802.11 was approved 21 March 1991.

Also recall this important fact (which affects old 802.11b/g only devices - and hence your reference to these channels): the signal modulation and channel spacing has changed since that time, so it's not really "re-add" - what you're asking today doesn't really exist (i.e. in most newer hardware).

Something else that doesn't come up - merely re-enabling these is no different than the inefficient use that an old WRT54G device would have on the band.

You'll also see why some people that talk about channel 14 are lost in history:

Wiki pic:

I think your theory sounds desirable; but you forget it's the same exact frequency space. Expressing your desire in other terms, you simply want to create lower bandwidth channels that still overlap the 20 MHz (and 40 MHz when there is no interference) channel updated standard.

For consideration, imagine those who want to force their 2.4 MHz device to broadcast in 40 MHz, for the same reasons you state.

That's literally why the engineers made non overlapping channels in 5.4 GHz when approving 802.11a on 16 September 1997.

I understand, but it is not the same to use a 5 Mhz channel in that time than in this one. Are there other ways to have more speed with new modulations or not?
Maybe you don't have to modify the standard of 40 years ago, but leave compatibility with old standards aside.

I didn't understand what you meant. In the image you can see that channel 14 does not overlap channel 11, but it does overlap channel 12 and 13.

Not necessarily because you could manually choose a channel where there is no network overlapping. Between channel 1 and 6 there is a space of 5 MHz. Between channel 6 and 11 as well. If there is no other network that uses a channel other than those 3, that space could be used to have a 5 MHz network and it would not be wasted as it is now.

Forcing the use of 5 or 20 MHz is not the same as 40 MHz. It is harmful to force the use of higher, not lower, bandwidths.

By saying that, you are giving me the reason that the 2.4 GHz band is being used inefficiently "to have more speed".

OK - it seems you're under the impression this space is only used by WiFi. If so, the space is not empty - the opposite is true in most areas. The technologies that use it also overlap and don't "co-exist" well (e.g. Bluetooth and WiFi).


1 Like