Does changing a Wifi channel affect the noise level?

[mummel]

I understand that the higher the SNR, the better. But I am using inSSIDer, and it only reports signal strength in DBM.

So my plan is to use inSSIDER to work through all 11 channels at 2.4ghz to try and find the channel with the best DBM reading.

But, does changing the channel affect the noise level, or is noise level constant (from devices such as phones, baby monitors etc)?

Because if noise is constant, then all I need to do is find the best DBM. But if noise changes with a channel change, then even if I find the channel with the best DBM, it may have more noise, with the net result of actually a worse signal (if this makes sense).

So basically, is noise constant or does it change with the channel? If it changes, are there any free PC programs that can provide me with a SNR reading.

Thanks all!

 

[theoak]

You will find that your dBm will not really change channel by channel. Noise can definitely change though. If you are on say 2.4 @ channel 6 but you've got folks on channels 5 and 7, there will definitely be more noise versus being on say just channel 11 with everyone around you being on channel 6 or lower.

Microwaves can also cause a good bit of noise on the 2.4 band. In fact, for me personally, I had to invest in a dual band adapter for my laptop because every time the wife turned the microwave on, my 2.4 band would fall to its knees.

A good way to find your best channel is to measure your throughput with something like TamoSoft (free). You might be surprised which channel gives you the best throughput.

 

[tofudreamer]

Not to mention that garage door openers, security systems, and hundreds more devices also operate in the "junk band" at 2.4 GHz.

5 GHz is be much better because it is reserved for WiFi. According to this, the new 802.11ac routers push MIMO technology further and can transmit over more wider channels simultaneously and give you much better speed (300%). The channels are also wider and less suceptible to noise. But don't get caught up with all the noise, at the end of the day the only thing that really matters is throughput.

 

[mummel]

Not to mention that garage door openers, security systems, and hundreds more devices also operate in the "junk band" at 2.4 GHz.

5 GHz is be much better because it is reserved for WiFi. According to this, the new 802.11ac routers push MIMO technology further and can transmit over more wider channels simultaneously and give you much better speed (300%). The channels are also wider and less suceptible to noise. But don't get caught up with all the noise, at the end of the day the only thing that really matters is throughput.

Thanks. Yeah I have a RT-N66U, so I have a 5ghz signal, but the only problem is that my home has multiple levels and the 5ghz signal cant penetrate the walls/floors (becomes unusable in certain areas). However, using 2.4ghz, I can get access throughout the house, albeit not perfect and slow.

I recently purchases a N56U on Black Friday for $40. My plan is to use it as a router in the basement and disable the wifi, and then move my N66U to a central location in the house (I have to have it on the far end of the house now close to my modem because of the way the home is wired). I'm hoping the 5ghz signal will work if I move the router, but I cant be certain. Perhaps I will then default back to 2.4ghz at that point and then try and figure out what channel is best. Do you think this is a good idea? I dont want to overthink it. I just want a reliable signal in all parts of my home that can handle streaming 1080p.

Im going to try Tamosoft and report back. Thanks guys.

 

[mummel]

You will find that your dBm will not really change channel by channel. Noise can definitely change though. If you are on say 2.4 @ channel 6 but you've got folks on channels 5 and 7, there will definitely be more noise versus being on say just channel 11 with everyone around you being on channel 6 or lower.

Microwaves can also cause a good bit of noise on the 2.4 band. In fact, for me personally, I had to invest in a dual band adapter for my laptop because every time the wife turned the microwave on, my 2.4 band would fall to its knees.

A good way to find your best channel is to measure your throughput with something like TamoSoft (free). You might be surprised which channel gives you the best throughput.

Thanks for the Tamosoft recommendation. I will check it out.

 

[RogerSC]

Noise is noise. It's variable over time, and one reading at one time of the day on each channel is only one data point. Lots of noise sources come and go, some are concentrated at certain times of the day, and neighbors can turn their wireless networks on and off, or get a better wireless router, and so on.

You just kind of take a whack at it, and if you have problems come back and look at conditions again. I agree about not overthinking it, as you can tell *smile*.

 

[stevech]

Please know that making noise or throughput tests, or busyness tests (channel utilization by others) ... is of course statistic and dependent on time of day, weekends, etc.
Esp. with streaming video on WiFi at neighbors'

 

[RogerSC]

Please know that making noise or throughput tests, or busyness tests (channel utilization by others) ... is of course statistic and dependent on time of day, weekends, etc.
Esp. with streaming video on WiFi at neighbors'

Yes, that's what I meant, a single test at a single point in time is only a starting point. You'd need to take samples over a period of time and analyze your data uisng statistics, and that's still no guarantee that things won't change in the future. That just tells you what's going up until the last sample was taken. But it's a place to start, and if things change, you'll be finding out *smile*.

 

[theoak]

I will add my 2 cents in agreement also.

inSSIDer during the day on the 2.4 band actually shows pretty clean. 6PM hits though and inSSIDer now looks like a city skyline.

Throughput tests during the day and at night gives me completely different results. I will add however that my downlink does not do too bad. My uplink though gets cut almost by half.

To add to the confusion ... and frustration ... I have a feeling I have some folks around me with their routers set to "auto" channel ... as they seem to jump around some from day to day.

 

[stevech]

measuring signal strengths of neighbors' WiFi is not useful.
What is important is their channel utilization - the percentage of air time they use, which for you, slows your throghput if you use a channel within 3 of their channel.

I don't know of a freeware tool that measures channel utilization and logs stats for, say, 24 hours.

 

[CaptainSTX]

One thing you can try to discourage over usage of the WiFi channels you would like to use is enabling Guest Networks or VLANs. With an ASUS router you will then be generating four SSIDs on a channel. For people or software that decides on what channel to use based on the number of SSIDs seen on a particular channel this may encourage them/it to select another channel.

For someone that knows what they are looking at this may not work since they will see that all four SSIDs have the same MAC address.

As for generating excessive RF interference it shouldn't since the four SSIDs are really just one radio.

 

[sinshiva]

lower frequencies generally travel further, i imagine it to be the case with the wifi spectrum, too. unfortunately, those are the most populated. that said, if you are out in the boonies, i'd run wifi at the lowest frequencies/channel possible.

 

[stevech]

negligible difference in low vs. high channel within either of the WiFi bands.
Of course, 5.8GHz has a slight disadvantage, easily offset via antenna gain.