Which 5Ghz channel to use?

25

5

My "better" router has 5GHz channels - 36,40,44,48,149,153,157,161

My not so much better router has 5GHz channels

  • 36,40,44,48,52,56,60,64,100,104,108,112,116,132,136,149,153,157,161

I am confused as to why the least expensive one has more channels compared to the "better" one. And also curious with which channel is best to use and what the difference is if I pick a lower channel compared to a higher numbered channel.

Aaron

Posted 2013-12-25T04:49:25.207

Reputation: 514

Answers

21

The channels that your "better" router has omitted are what is known as the dynamic frequency selection or DFS channels. These channels have been allows by the FCC for use, but they must employ a means of detecting and shifting off the channel if they detect another licensed use of the spectrum (namely some forms of weather radar and very limited military use).

Many enterprise deployments will avoid these channels if possible for the same reason.

It sounds the like the vendor of your "better" router has decided to avoid those complexities and simply ignore that they exist. This still leaves you eight non-overlapping channels which is five more than you have in 2.4 GHz (which has only three non-overlapping channels) and far more than you need in any residential/consumer deployment.

As to which to use, download a copy of inSSIDer and pick the one where you see no or the lowest signal strength in use.

YLearn

Posted 2013-12-25T04:49:25.207

Reputation: 1 741

A user tried to edit and I felt it was at least worth a comment. The license model for inSSIDer has changed and now the personal edition (which is a bit trickier to find) license costs $20. The office license is $149.

– YLearn – 2016-08-03T17:50:41.197

Acrylic Wifi Home (https://www.acrylicwifi.com/en/wlan-software/wlan-scanner-acrylic-wifi-free/) also shows you the networks on different channels and is free.

– Rory – 2016-09-24T19:47:37.573

When you say my vendor "decided to avoid those complexities" , you mean that the router ignores the fact that weather radar and military may use these channels and just allows me to pick them anyway? – Aaron – 2013-12-25T05:06:03.070

3No, the DFS channels require that the AP/router using them needs to be able to identify when such a device is/starts operating in the area and "dynamically" change to a different channel. Your better router avoids this complexity by simply not allowing you to use these channels...since you can't use them it doesn't need to detect if such devices are operating in the same RF space. – YLearn – 2013-12-25T05:25:30.077

Ah, so the channels it uses are already omitted. So I best try to match those channels to the older router that shows everything. It's Netgear btw. I also thought the higher or lower channels affected range, I wasn't certain about that. – Aaron – 2013-12-25T05:27:25.460

Highly recommend using inSSIDer, if you can move to a clear channel none of your neighbors are using, you'll be in good shape! – MDT Guy – 2013-12-27T20:56:07.443

7

The best channel to use is the lowest channel that has a high transmit power. Lower frequencies penetrate walls more easily, and there is a significant difference between channel 36 (5180Mhz) and channel 165 (5825Mhz).

However up until 2014 there were limits on transmit power for the lower frequencies, so depending on your router you may need to use a higher channel to get larger transmit power.

So in reality you should just try channels within the various 5Ghz bands and see which gives a better signal. Then choose the lowest channel within that band.

CpnCrunch

Posted 2013-12-25T04:49:25.207

Reputation: 171

6

Your "better" router probably supports that fuller list of channels as well, but it doesn't show you those channels for manual channel selection. As @YLearn's Answer mentioned, those other channels (52-144) require DFS, which means that your router might not be able to use some of those channels even if you had picked them.

It's confusing to users if you let them manually pick a channel, and then you end up having to use a different channel anyway. It makes users feel like you lied to them when you let them manually pick a channel even if you knew you might not be able to honor their choice. And you sort of did lie to them. So better router vendors only let you manually pick the channels they know for sure they'll be able to use. To access any other channel, you just have to rely on automatic channel selection.

Spiff

Posted 2013-12-25T04:49:25.207

Reputation: 84 656

Yeah didn't know what it meant. No documentation on it either. I assumed different channels gave better range but not sure. Will have to run inssider to be sure. – Aaron – 2013-12-27T12:10:13.147

3

To answer the other half of your question, channels 149-161 will provide better range than 36-48. The higher band broadcasts at a stronger signal than the lower band (I believe this is due to the standard).

Bigbio2002

Posted 2013-12-25T04:49:25.207

Reputation: 3 804

2Lower frequencies provide better penetration through walls, so choose the lowest channel you can. – CpnCrunch – 2015-12-07T00:44:35.343

@CpnCrunch The difference in wall penetration between 2.4 and 5 GHz is significant (a factor of 2 - that's an octave). The difference between 5.2 and 5.8 GHz is not. – Jamie Hanrahan – 2019-02-24T03:36:48.393

This isn't necessarily true in all areas. This isn't due to the IEEE 802.11* standards, it's due to regional radio regulatory agencies (FCC, ETSI, etc.). So if the region you live in allows higher power in the upper band, the upper band is better. But if not, then it's not. – Spiff – 2013-12-27T21:24:53.737

Very random for different locations. That's not a good standard.. – Aaron – 2013-12-27T23:32:30.000

0

If you are in a house where your wifi needs to penetrate multiple walls and/or floors - choose a low channel. If your in a loft apartment or want your wifi to extend into the back yard with a near clean line of sight, choose a higher channel.

Greg

Posted 2013-12-25T04:49:25.207

Reputation: 1