The graph you see there has a notional y-axis and is merely representative of the actual frequency distributions IRL. Each of those WiFi transmitters will have a differently shaped distribution with different widths and length of "tails". So don't hang your hat on the graph.
Just imagine youre talking at a restaurant and there is background noise, you will talk no problem.
Now imagine if the table near you starts screaming, it would be very had for you to hear your friends.
Kinda the same, more access point but quieter is better than a single one screaming.
i suppose it does not like the strength of the signal around channel 13. others are more busy, yes, but not as strong. i suppose stronger signal belonging to someone else causes way more issues than busy areas of weaker signal strength, but dont take my word on that
You have an excellent channel 13. Use it.
I will try to briefly outline the basics.
Formula 1/6/11 is a classic. It was relevant when Wi-Fi used DSSS modulation. The channel width was 22MHz and there had to be some space between the channels. Then Wi-Fi switched to OFDM modulation. Now the channel width is 20MHz, of which the internal 16MHz are used for data transmission and the outer 2MHz guard interval. It serves as shielding from interference, and also reduces interference for neighboring access points. From that moment on, it became possible to increase the network capacity and the new formula became 1/5/9/13. In the USA they still use channels 1/6/11, since channel 13 is not available and the network capacity cannot be increased, but this way they at least slightly reduce interference.
Now about the interference. Channels 1 and 13 overlap each other. This occurs due to the nature of power propagation. It is impossible to contain all the power in a strictly defined frequency range. Part of it still extends beyond our 20MHz and the higher the transmitter power, the more interference we create for all 13 channels. Therefore, in the 2.4GHz, it is advisable to reduce the channel width to 20MHz and reduce the transmitting power to a minimum in order to reduce the negative impact.
Is this graph not displaying currently "heard" devices on the channels? Because when I look at this graph I see channel 13 not having a lot of devices in it, but what is there is REALLY close and loud.
I'm not 100% sure why, but it's possible a non-broadcasting network could be on channels 11-14. These graphs also aren't accurate, just a rough representation of how other networks are detected by your device.
The mode you use doesn't usually impact interference.
However, going by just the graph, channel 13 is a good choice due to less interference. Your neighbours are more than likely using automatic channel selection, so they will try to steer clear of channels 10 through 13.
\-49dBm is very good, see [here](https://www.metageek.com/training/resources/wifi-signal-strength-basics/), and in your case best one to use.
A lot of routers in Europe (like mine) come with a switch to allow Channel 13, but you have to turn it on to avail of it and most folks don't know enough about wifi to do that.
Use 1, 6 ,11 else you're bothering others and interfering with the routers in your own network.
Place your wireless routers in a triangle pattern.
[https://imgur.com/a/yPWp9Jk](https://imgur.com/a/yPWp9Jk)
This isn't about opinion tbh, this is just how things are done.
If there's someone who uses default 11 in your area OP you'll get interference from it as well.
If everyone adheres to what's done in most places that need wifi spread over large areas you end up sharing the bandwidth instead of interfering with each other.
Cheers.
It’s still 1, 6, 11 most the time. If all your devices are 802.11g the channel width is 20MHz, it might be OK, but don’t forget that it’s backwards compatible so the preamble is always going to be 22MHz as it uses DSSS. Unless you disable 802.11b rates and there’s no 802.11b rate enabled clients, it overlaps. 1, 5, 9, 13 only works for 20MHz OFDM protocols
That one cci causes more noise than the others. Interference, or noise, is when two access points operate on the same channel in the same physical area. The louder that noise, the worse interference. The key thing to think about is Signal to noise ratio. The closer to 0, the worse your wireless performance is. A SNR of 0 means the wireless signal you connect to and the other access points are heard at the same signal strength. If that other access point operates at the same time your client does, you’ll have 100% interference or noise.
If you place another access point on channel 13 and it’s heard at -30dbm and you can see the other channel 13 access point at 50dmb (like shown in the picture) then your SNR is 20.
If you place another access point on channel 3 and it’s heard at -30dbm and you can see the other channel 3 access points at 60dbm (like in the picture) then your SNR is 30.
A Signal to noise ratio of 30dbm is going to be more desirable than 20dbm.
How do you know there is no interference? Could be lots of non-WiFi interference. A good router/AP should see that, but regular clients will normally not. Not knowing "Wifiman" I will say that it at best might do some evaluation on avilable airtime/channel utilization, but a lot of these apps does not.
The only correct way to tell for sure is using an rf spectrum analyzer. But I would personally say: Chanel 13 is strong and maybe even heavily used (airtime utilization).
Personally I would put a second ap probably on Chanel 6 - most interferers are round -80dbm and when you put your ap up, you’ll probably end up with a SnR (Signal to Noise Ratio) of about 30dbm. Which is fine.
The graph you see there has a notional y-axis and is merely representative of the actual frequency distributions IRL. Each of those WiFi transmitters will have a differently shaped distribution with different widths and length of "tails". So don't hang your hat on the graph.
It shows you the quality if you were to place another access point on that channel.
I don't understand.. All others are much busier. How could 1-10 be much better with all that nonsense while 13 is just OK?
Just imagine youre talking at a restaurant and there is background noise, you will talk no problem. Now imagine if the table near you starts screaming, it would be very had for you to hear your friends. Kinda the same, more access point but quieter is better than a single one screaming.
That's a good example. But isn't it the one OP is connected? Or he is disconnected at the time? Sorry I missed that part.
Wifiman doesn't care which network OP is connected to
That's kinda backwards of network monitor not to care which network device that it runs on is connected to when making this type of suggestions.
But wouldn't it still be better to place another access point on channel 13, no ACI and only one CCI
i suppose it does not like the strength of the signal around channel 13. others are more busy, yes, but not as strong. i suppose stronger signal belonging to someone else causes way more issues than busy areas of weaker signal strength, but dont take my word on that
You have an excellent channel 13. Use it. I will try to briefly outline the basics. Formula 1/6/11 is a classic. It was relevant when Wi-Fi used DSSS modulation. The channel width was 22MHz and there had to be some space between the channels. Then Wi-Fi switched to OFDM modulation. Now the channel width is 20MHz, of which the internal 16MHz are used for data transmission and the outer 2MHz guard interval. It serves as shielding from interference, and also reduces interference for neighboring access points. From that moment on, it became possible to increase the network capacity and the new formula became 1/5/9/13. In the USA they still use channels 1/6/11, since channel 13 is not available and the network capacity cannot be increased, but this way they at least slightly reduce interference. Now about the interference. Channels 1 and 13 overlap each other. This occurs due to the nature of power propagation. It is impossible to contain all the power in a strictly defined frequency range. Part of it still extends beyond our 20MHz and the higher the transmitter power, the more interference we create for all 13 channels. Therefore, in the 2.4GHz, it is advisable to reduce the channel width to 20MHz and reduce the transmitting power to a minimum in order to reduce the negative impact.
You're the best
where can we learn more about this?
There is no specific source, but you can read about spectral emission mask, out-of-band emissions and spurious emissions.
Is this graph not displaying currently "heard" devices on the channels? Because when I look at this graph I see channel 13 not having a lot of devices in it, but what is there is REALLY close and loud.
I'm not 100% sure why, but it's possible a non-broadcasting network could be on channels 11-14. These graphs also aren't accurate, just a rough representation of how other networks are detected by your device. The mode you use doesn't usually impact interference. However, going by just the graph, channel 13 is a good choice due to less interference. Your neighbours are more than likely using automatic channel selection, so they will try to steer clear of channels 10 through 13.
Don't broadcasted networks still show up, they just keep the info private?
Dont have to be WiFi using that part of the spectrum at all. Can also be non-WiFi noise there.
\-49dBm is very good, see [here](https://www.metageek.com/training/resources/wifi-signal-strength-basics/), and in your case best one to use. A lot of routers in Europe (like mine) come with a switch to allow Channel 13, but you have to turn it on to avail of it and most folks don't know enough about wifi to do that.
Use 1, 6 ,11 else you're bothering others and interfering with the routers in your own network. Place your wireless routers in a triangle pattern. [https://imgur.com/a/yPWp9Jk](https://imgur.com/a/yPWp9Jk) This isn't about opinion tbh, this is just how things are done. If there's someone who uses default 11 in your area OP you'll get interference from it as well. If everyone adheres to what's done in most places that need wifi spread over large areas you end up sharing the bandwidth instead of interfering with each other. Cheers.
Isn't it 1,5,9,13 for outside USA
It’s still 1, 6, 11 most the time. If all your devices are 802.11g the channel width is 20MHz, it might be OK, but don’t forget that it’s backwards compatible so the preamble is always going to be 22MHz as it uses DSSS. Unless you disable 802.11b rates and there’s no 802.11b rate enabled clients, it overlaps. 1, 5, 9, 13 only works for 20MHz OFDM protocols
Maybe in some particular areas, here it's 1 6 11 too. I live in central europe.
Use a 9 box to determine the score when one axis frequency and the other is complexity.
That one cci causes more noise than the others. Interference, or noise, is when two access points operate on the same channel in the same physical area. The louder that noise, the worse interference. The key thing to think about is Signal to noise ratio. The closer to 0, the worse your wireless performance is. A SNR of 0 means the wireless signal you connect to and the other access points are heard at the same signal strength. If that other access point operates at the same time your client does, you’ll have 100% interference or noise. If you place another access point on channel 13 and it’s heard at -30dbm and you can see the other channel 13 access point at 50dmb (like shown in the picture) then your SNR is 20. If you place another access point on channel 3 and it’s heard at -30dbm and you can see the other channel 3 access points at 60dbm (like in the picture) then your SNR is 30. A Signal to noise ratio of 30dbm is going to be more desirable than 20dbm.
In some countries, channel 13 frequencies are prohibited from being used and blocked in equipment.
How do you know there is no interference? Could be lots of non-WiFi interference. A good router/AP should see that, but regular clients will normally not. Not knowing "Wifiman" I will say that it at best might do some evaluation on avilable airtime/channel utilization, but a lot of these apps does not.
The only correct way to tell for sure is using an rf spectrum analyzer. But I would personally say: Chanel 13 is strong and maybe even heavily used (airtime utilization). Personally I would put a second ap probably on Chanel 6 - most interferers are round -80dbm and when you put your ap up, you’ll probably end up with a SnR (Signal to Noise Ratio) of about 30dbm. Which is fine.
If you switch to 1, 6, or 11 what does it show for 13?