WIFI Noise Level constantly at -100 dBm


I am fairly new to OpenWRT. I am using the Xiaomi Mi Router 4A Gigabit Edition.
My problem is that I want to configure my wireless network right and for that I would need not only the RSSI value and channels but also the noise value.
When typing in the command "iwinfo", it shows me "Noise: unknown". I have read that the driver can influence whether this works or not, but can I change the driver and is there even another driver for my device?
I also found a similar post: WNDR3700v3 Noise Level

Thank you for your help.

What is the SNR?

Hover the mouse over the WiFi bars.

Do you mean on a client, for example a phone or notebook?
They only show the RSSI, and I would need the RSSI and the Noise to calculate the SNR. From digging around the internet I know that some devices that run OpenWRT support this feature, but my access point only shows "Noise: unknown".

The Status page in LuCI.

There it shows me Signal: -56dBm and Quality: 74%
Can you link me a page where these values are explained? I am a little bit confused, because on Channel Analysis it shows "Signal: Local Interface: -10 dBm".

What is the SNR?

That means that the default BSSID (MAC address) has no associations.

Compare the BSSID in Channel Analysis to the one on the Status page in the Wireless section.

SNR is this: https://www.netspotapp.com/signal-to-noise-ratio.html

My BSSID in Channel Analysis is the same with the BSSID on the overview page.

I know what SNR is...

As mentioned above, I'm asking you to provide your SNR numbers, by hovering your mouse over the WiFi bars on the LuCI Status page for each connected device.

So if that BSSID has no associations...that's why it's displaying -10 dBm in Channel Analysis.

Okay, here is a screenshot:

But I don't think the device can detect noise, since, when typing in "iwinfo" in the terminal, it says "Noise: unknown". But maybe one can change that through changing the driver or something of this nature.

Here is another screenshot:

Your signal strength is good, but not great.

You might check how many people in your neighborhood are using channel 11.

I would get a WiFi analyzer (lots of free apps) and watch the 2.4 Ghz band, especially during peak hours.

You might consider moving some of your devices to 5 Ghz.

Bottom line -100 dBm for noise is not outrageous.

I usually bounce between -95 and -108, and don't have any issues.

I do have better signal strength, so my SNR's range from the mid-40's to the low 50's.

No drops.

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It could very well be that 2.4GHz is getting to it's limits in my area. There are many access points around our apartment that use the 2.4GHz band. But I want to further research this problem I have, and for that I need the SNR.

But I do not think that the signal, that is displayed for each associated station, is the SNR but just the Signal. When I go to Status > Realtime Graphs > Wireless > wlan0, I see that the Noise Level stays the same at -100 dBm all the time. Here is a screenshot:

And when I connect to the access point via SSH, and type in "iwinfo", I see the information "Noise: unknown". I think, as of now, my access point cannot measure the noise, and thats why it's always at -100 dBm. My inital question was, if I can get the access point to meassure the noise, so that I can then calculate the SNR. Maybe I just have to install a new driver on my access point, but I don't know. My access point is a Xiaomi Mi Router 4A Gigabit Edition.

Here is another screenshot:


Yeah, I see the same thing there for my 2.4 Ghz radio.

However, it's not consistent with what I see on the Status page (OpenWRT 21.02.1)...which also shows the SNR on for my devices, and it doesn't match the WiFi analyzer I use as a "second opinion".

As mentioned, get an analyzer and start gathering info with it.

I tried different devices (notebooks and phones) and different wifi analyzers, but non show the noise.
But whatever, maybe somebody finds a solution, so that my access point can measure it. And maybe I should switch to 5GHz, but I then would need two more access points. But 2.4GHz looks like this at my place:

The transmit power is turned to the lowest setting on my access point.

But still, thanks for your help :+1:

Since I'm not familiar with this and since noise might not be a fixed value but change over time: Would you mind explaining a bit more for what exactly you need the noise figures?

I need the noise value to be able to calculate the SNR value. More information here:

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I don't know of any OpenWrt chipset / driver that actually measures noise.

In any urban location, consider the 2.4 band will be unusable and move on to 5 GHz.

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Thanks for the advice, there probably isn't anything else I can do.