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    Question How can one SSID use two channels?

    Several sniffers (AcrylicWi-Fi and inSSIder) show that I detect one SSID broadcasting on 2 channels (7 + 11).
    Apparently a neighbor but I don't know who. How did he or she setup to use 2 channels?

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    WS Lounge VIP mrjimphelps's Avatar
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    There could be a wifi range extender set to the same SSID, but to a different channel, than the router. So, in this example, the router could be set to channel 7, while the extender could be set to channel 11.

    7 and 11 might conflict with each other (there would be overlap, because they are too close together), so it would be better to go with 6 and 11.

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    It's because the adapter uses 20MHz and 40MHz that you get the two channels and there is usually a difference of 4 between them, so changing to use the main channel as 6 will produce 6+10.

    The 20MHz are the g data transfer speeds and the 40MHz gives you the n data transfer speeds.

    These are what you see for the adapter when it shows as b/g/n

    There are limited changes you can make to either by going into Device Manager/Network adapters - right click on the wireless adapter and select Properties, then under the Advanced tab you will see the items which will enable the dropdown for each - but they are best left at default.

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    Quote Originally Posted by mrjimphelps View Post
    There could be a wifi range extender set to the same SSID, but to a different channel, than the router. So, in this example, the router could be set to channel 7, while the extender could be set to channel 11.

    7 and 11 might conflict with each other (there would be overlap, because they are too close together), so it would be better to go with 6 and 11.
    Thanks. I knew something about extenders (a friend installed one, way out of my range) but I did not know that they could use different frequencies from the router.

    If I can find out whose router is showing as 7 + 11 I will pass on your advice.

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    Quote Originally Posted by Sudo15 View Post
    It's because the adapter uses 20MHz and 40MHz that you get the two channels and there is usually a difference of 4 between them, so changing to use the main channel as 6 will produce 6+10.

    The 20MHz are the g data transfer speeds and the 40MHz gives you the n data transfer speeds.

    These are what you see for the adapter when it shows as b/g/n

    There are limited changes you can make to either by going into Device Manager/Network adapters - right click on the wireless adapter and select Properties, then under the Advanced tab you will see the items which will enable the dropdown for each - but they are best left at default.
    I certainly don't understand this. According to PC Magazine Encyclopedia, an 'adapter' is a device which adds connectivity to a laptop or desktop computer. I would think that such a device could not send a signal, i.e. could not be an SSID.

    Hope it is clear that this is just an SSID I detect - I have no control over it.

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    Quote Originally Posted by heritage View Post
    Several sniffers (AcrylicWi-Fi and inSSIder) show that I detect one SSID broadcasting on 2 channels (7 + 11).
    Apparently a neighbor but I don't know who. How did he or she setup to use 2 channels?
    It is possible one is the 2.4GHz radio and the other 5GHz radio.

    David

    Just because you don't know where you are going doesn't mean any road will get you there.

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    I understand that it is just one or more of local users that your NIC is picking up and that you have no control over it.

    Scroll down this article on setting up a Netgear router and you will see what I mean where it lists the combo of channels - it has nothing to do with extenders using different channels - it's the dual Channel Width that N routers broadcast on.

    http://documentation.netgear.com/dg8...eless.4.3.html

    Go into Device Manager/Network adapters - right click on the wireless adapter and select Properties.

    Under the Advanced tab click on Bandwidth and using the dropdown you will see how you can change this to just 20MHz where your adapter is using 20 - 40MHz by default.

    You can also change the Channel Width (Bandwidth) in a router - sometimes this is necessary if you are having problems connecting an Apple device as they weren't keen on the dual channel width and you had to drop the router to use just the 20MHz band and this can apply to other devices when you are trouble shooting a connectivity problem.

    What does inSSIDer give for your SSID ?

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    Quote Originally Posted by wavy View Post
    It is possible one is the 2.4GHz radio and the other 5GHz radio.

    You have completely different channel numbers on 5GHz.

    See the Netgear link I've posted which explains why inSSIDer displays two channels.
    Last edited by Sudo15; 2015-10-06 at 19:27.

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    Yep I see that neither 7 nor 11 are used for the 5GHz bands in the states!

    David

    Just because you don't know where you are going doesn't mean any road will get you there.

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    Quote Originally Posted by Sudo15 View Post
    it has nothing to do with extenders using different channels - it's the dual Channel Width that N routers broadcast on.
    I'm just curious: why are you certain that this couldn't be a router/extender combo, both using the same SSID but different channels?

    I set up an extender at my church, with the extender using the same SSID as the router. However, I didn't set the channels, because the extender setup program did all of the configuration automatically. And I've never used any sort of sniffer on the network, so I have no idea what the channels are set to.

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    Quote Originally Posted by mrjimphelps View Post
    I'm just curious: why are you certain that this couldn't be a router/extender combo, both using the same SSID but different channels?

    I set up an extender at my church, with the extender using the same SSID as the router. However, I didn't set the channels, because the extender setup program did all of the configuration automatically. And I've never used any sort of sniffer on the network, so I have no idea what the channels are set to.
    Because of the opening post.

    I think the link I'd posted regarding setting up a Netgear router illustrates what I was trying to explain.

    Run inSSIDer3 on your machine and/or the one at your church and you will see similar entries where their routers are broadcasting on two channels - some may just be displaying one, in which case they may have changed from 20 - 40MHz to just 20MHz for possible connectivity problems with an external device or the router isn't a N router.

    When it has loaded, click on the Networks tab http://www.techspot.com/downloads/5936-inssider.html

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