New router - printer not working
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Nope, you should ALWAYS use channels 1, 6 and 11 as these are the only 3 channels in the 2.4Ghz band that DO NOT overlap with each other. Any other channel will only give you space for 2 non-overlapping channels.
Some wireless access point vendors automatically choose one of these 3 channels when set in auto-mode (for example Ubiquiti).
Absolute tosh!!! You need to pick the channel with the least interference where you're using the router...if that happens to be on 2,4,5,7,8,9 or 10 then so be it. Use wifi analyser on an android phone to walk around your house in the evening and see how the RF is looking.
My 2.4GHz wifi just happens to be on channel 2 at the moment, I was using 9 until a close neighbor got a new router (another on ch.11) which, as it was closer and so a higher-power interference causing problems..
Around my house I have 3 using ch.1, 3 using ch.6, 1 using ch.7 (a recent mover, was on 11) and 5 using ch.11. Channel 2 works best as the ones using ch.1 and 3 are lower power than those on 11 and 7, so it's the minimum of bandwidth crossover and power conflicts.
...and yes, I wifi-survey my house several times a week to ensure I'm using the best channel for 2.4GHz, it's a case of having to...Thankfully my 5GHz is on it's own
......Gettin' There, Wherever There is......
I have a dodgy "i" key, so ignore spelling errors due to "i" issues, ...I blame Apple
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Do you know how WiFi radio waves work? It doesn't sound like you do.Absolute tosh!!! You need to pick the channel with the least interference where you're using the router...if that happens to be on 2,4,5,7,8,9 or 10 then so be it. Use wifi analyser on an android phone to walk around your house in the evening and see how the RF is looking.
My 2.4GHz wifi just happens to be on channel 2 at the moment, I was using 9 until a close neighbor got a new router (another on ch.11) which, as it was closer and so a higher-power interference causing problems..
Around my house I have 3 using ch.1, 3 using ch.6, 1 using ch.7 (a recent mover, was on 11) and 5 using ch.11. Channel 2 works best as the ones using ch.1 and 3 are lower power than those on 11 and 7, so it's the minimum of bandwidth crossover and power conflicts.
...and yes, I wifi-survey my house several times a week to ensure I'm using the best channel for 2.4GHz, it's a case of having to...Thankfully my 5GHz is on it's own
Let's start from the basics. 2.4 Ghz has approx 13 channels (depending in which country you are). Each channel, in a standard configuration, has a bandwidth of 22 Mhz.
If we take channel 6 as an example, its center frequency is 2437 Mhz, however it transmits between 2426 and 2448 Mhz. That shows you that channels 2, 3, 4, 5 and 7, 8, 9 and 10 all have a portion of their bandwidth that overlaps channel 6. The only channels that are completely isolated are 1 and 11.
What happens if you use two radios transmitting one on channel 3 and the other on channel 5? It happens that both radio signals partially overlap with each other, and this creates noise and lower throughput.
Surprisingly, using the same channel on two different access points (i.e. channel 11 and 11) will have a much minor impact, as both radios will be able to understand each others transmissions and wait for their turn to transmit accordingly. This does not happen with overlapping channels like 3 and 5 because part of the transmission is lost from the other radio's point of view (radio on channel 3 can only listen to part of what radio on channel 5 transmits, therefore cannot coordinate with it).0 -
Do you know how WiFi radio waves work? It doesn't sound like you do.
Let's start from the basics. 2.4 Ghz has approx 13 channels (depending in which country you are). Each channel, in a standard configuration, has a bandwidth of 22 Mhz.
If we take channel 6 as an example, its center frequency is 2437 Mhz, however it transmits between 2426 and 2448 Mhz. That shows you that channels 2, 3, 4, 5 and 7, 8, 9 and 10 all have a portion of their bandwidth that overlaps channel 6. The only channels that are completely isolated are 1 and 11.
What happens if you use two radios transmitting one on channel 3 and the other on channel 5? It happens that both radio signals partially overlap with each other, and this creates noise and lower throughput.
Surprisingly, using the same channel on two different access points (i.e. channel 11 and 11) will have a much minor impact, as both radios will be able to understand each others transmissions and wait for their turn to transmit accordingly. This does not happen with overlapping channels like 3 and 5 because part of the transmission is lost from the other radio's point of view (radio on channel 3 can only listen to part of what radio on channel 5 transmits, therefore cannot coordinate with it).
:rotfl: I've only been an Electronic Engineer specialising in RF systems for 30+ years, so yes, I think I do
Much of what you state is accurate, however you ignore relative signal strengths these can seriously degrade the quality of both broadcasts, and even a minor phase difference between two broadcasts on the same channel (irrespective of signal strength) will have an impact. In a wifi context, this can (and often does) lead to devices either losing connection to the source or being connected but with no authentication, etc. as enough of the data has been corrupted.
This is why channel selection in a broadcast environment is very often a compromise, and even more important in the current (mostly) saturated RF environment than it ever has been....to blankly state that ONLY channels 1, 6 or 11 should be used is just plain wrong. If you'd have said 1,6 and 11 are the channels to try first - no problem with that, but without surveying the operating environment first you're still only guessing.........Gettin' There, Wherever There is......
I have a dodgy "i" key, so ignore spelling errors due to "i" issues, ...I blame Apple0 -
Sorry, but still doesn't look like you understood what I said.:rotfl: I've only been an Electronic Engineer specialising in RF systems for 30+ years, so yes, I think I do
Much of what you state is accurate, however you ignore relative signal strengths these can seriously degrade the quality of both broadcasts, and even a minor phase difference between two broadcasts on the same channel (irrespective of signal strength) will have an impact. In a wifi context, this can (and often does) lead to devices either losing connection to the source or being connected but with no authentication, etc. as enough of the data has been corrupted.
This is why channel selection in a broadcast environment is very often a compromise, and even more important in the current (mostly) saturated RF environment than it ever has been....to blankly state that ONLY channels 1, 6 or 11 should be used is just plain wrong. If you'd have said 1,6 and 11 are the channels to try first - no problem with that, but without surveying the operating environment first you're still only guessing...
If you use channels other than 1, 6 and 11 you will have ONLY TWO non-overlapping channels, due to the bandwidth of 2.4Ghz channels. There is no ifs or buts. If you use any other channel, you will overlap, and this causes interference.
Whatever survey you do, if channel 1 and 6 are overcrowded, you can only use channel 11. ANY OTHER channel will overlap with either channel 1 or channel 6, and this can only degrade the performance, there is no benefit.
If all 3 channels are being used, it is still a much better choice to stick to one of those 3, rather than choosing an overlapping channel (i.e. 3 or 7), because of the reasons I explained earlier.
If you have some time and want to freshen up your knowledge about wifi, have a look at this test that Cisco made some time ago (I cannot find the original link I'm afraid): link
You will see how using overlapping channels will always degrade performance.
I will quote the conclusion of the test:Many have long recommended a three-channel approach to provide nonoverlapping channels. We still recommend such installations for 2.4-GHz WLANs, for both 802.11b and 802.11g technologies. A four-channel scheme can cause severe issues when the system is brought online and the number of users starts to increase.
In a four-channel design, the signal of one device is noise to another device. Even in a design where a channel 1 cell would never overlap a channel 4 cell, for example, you must still account for clients transmitting that are not in the same location as the access point. By looking at only the access points, you are ignoring the majority of radios in your network. Virtually all new radio deployments support 802.11g and/or 802.11a and thus OFDM, which has much more sideband energy than 802.11b.
If you design a system with four channels, the risk of interference between cells greatly increases, resulting in poor performance and lower throughput. As the volume of users and bandwidth needs increase, problems will slowly arise, making it necessary to resolve the issue at a later date. Start by using three nonoverlapping, noninterfering channels.0 -
No, I get the point completely...any overlapping channel absolutely will cause some degradation, I never once said it wouldn't.
What you are ignoring is the concept that in any given operating environment, you have to select, from the limited range available, the best channel for minimal interference possible. As more & more WAPs come into use, e.g. on a housing estate, blindly limiting yourself to 3 channels is more likely to lead to poor wifi performance, as you and uncle tom cobley and all are using 1, 6 and 11(which, btw, is not "completely isolated" as you stated earlier). It could work for you on one of those channels, depending on the proximity and therefore relative signal strength of the other users on "your" channel..
"As the volume of users and bandwidth needs increase, problems will slowly arise, making it necessary to resolve the issue at a later date. Start by using three non-overlapping, non-interfering channels."
Yes, this paper was some time ago, and whilst the advice at the time was sound, the ship of overcrowded airwaves has well and truly sailed since then, and so we have to act (and advise) accordingly....
..and a further quote from that paper:-
"The level of RF energy that crosses between these channels determines interference. Radios do not have an exact edge to their channel, and energy spreads beyond the edges of the channel boundaries. However, the overall energy level drops as the signal spreads farther from the center of the channel. "
further backs up my point....this is nothing new in RF.........Gettin' There, Wherever There is......
I have a dodgy "i" key, so ignore spelling errors due to "i" issues, ...I blame Apple0 -
No, those 3 channels ARE completely isolated....all are using 1, 6 and 11(which, btw, is not "completely isolated" as you stated earlier)...
Channel 1 transmits between 2401 and 2423.
Channel 6 transmits between 2426 and 2448
Channel 11 transmits between 2451 and 2473.
As you can see, those channels NEVER overlap.
If everybody used channels 1, 6 or 11 there would be NO overlap and NO noise.
If you are still convinced that that's not the case, give me an example of when you would use a channel other than those 3 and I will demonstrate why it's wrong.0 -
Yes, overcrowded 2.4Ghz networks are another reason why we should stick to those instructions even more strictly now.Yes, this paper was some time ago, and whilst the advice at the time was sound, the ship of overcrowded airwaves has well and truly sailed since then, and so we have to act (and advise) accordingly....0 -
No it doesn't."The level of RF energy that crosses between these channels determines interference. Radios do not have an exact edge to their channel, and energy spreads beyond the edges of the channel boundaries. However, the overall energy level drops as the signal spreads farther from the center of the channel. "
further backs up my point....
Radios do not have an exact edge, that's obvious, but the closer you get to a channel, the more overlap you have. And the only way of reducing this overlap to a minimum is to use those 3 channels.
Channel 1 and 6 *may* overlap, slightly, in some circumstances, .
Channel 1 and 2, 3, 4 or 5 will *ALWAYS* overlap. And that's the reason why you shouldn't be using them.
As I said, give me a scenario where you would use channel 5, for example, and I will show you why that would be wrong.0 -
No, those 3 channels ARE completely isolated.
Channel 1 transmits between 2401 and 2423.
Channel 6 transmits between 2426 and 2448
Channel 11 transmits between 2451 and 2473.
As you can see, those channels NEVER overlap.
If everybody used channels 1, 6 or 11 there would be NO overlap and NO noise.
If you are still convinced that that's not the case, give me an example of when you would use a channel other than those 3 and I will demonstrate why it's wrong.
No, those 3 channels are only completely isolated FROM EACH OTHER !!!
OK, I'll give you a real-world example....
I can "see" 3 WAPs on ch1, and 3 on ch6 when upstairs in my house. The typical signal strength from the ch1 WAPs is -95dB, and -75dB from the ch6 WAPs. My WAP is producing -55dB at that same physical place. What channel am I going to set my WAP to?? I want the minimum signal overlap as possible (assume 7-11 is way more overcrowded with stronger WAPs so isn't viable...
Optimal throughput is actually achieved in this scenario by using ch2....using ch1 leads to infrequent, intermittent loss of authentication. 3,4,and 5 give increasing amounts of loss of authentication and signal attenuation as you get closer (and therefore more RF energy) to and overlapping with ch.6..........Gettin' There, Wherever There is......
I have a dodgy "i" key, so ignore spelling errors due to "i" issues, ...I blame Apple0
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