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LetSleepingKidsLie

Member

Registered: 2011-03-09

Posts: 4

Downgrade an 802.11n WiFi card to either b or g

My new laptop has a built-in WiFi card. It is a Broadcom 802.11n card. The brcmsmac driver works fine. It is able to see the router the printer is on, but it is not able to see any of the other WiFi access points in the neighborhood including the WiFi provided by our apartment.

Looking around online I found that the problem is likely that the 802.11n protocol is not supposed to work with encryption other than WPA2. My printer's router is using WPA2, but the apartment's internet router is using WEP (I don't control the router - I don't get to make the choices on it).

For some reason, the brcmsmac driver is not automatically downgrading to the 802.11g connection protocol. Is there any way of forcing it to do so?

LetSleepingKidsLie

Member

Registered: 2011-03-09

Posts: 4

Re: Downgrade an 802.11n WiFi card to either b or g

I found that iwconfig has an option for setting the modulation, but it is not supported for my card.

]# iwlist wlan0 modulation
wlan0     unknown modulation information.

I am also starting to think that my problems don't have anything to do with the connection protocol. Some of the other networks in the neighborhood are also using WPA2 encryption and my internal network card doesn't see them either.

Does anyone have any idea why I can see so few networks with my on-board wireless card?

# iwlist wlan0 scan | grep ESSID
                    ESSID:"madhouse"

# iwlist wlan1 scan | grep ESSID
                    ESSID:"MOTOROLA-9157B"
                    ESSID:""
                    ESSID:"Mine"
                    ESSID:"madhouse"
                    ESSID:""
                    ESSID:"Baxter"
                    ESSID:"Mecham"
                    ESSID:"2WIRE826"
                    ESSID:"WoodshedD"
                    ESSID:""
                    ESSID:"rasp_garden_wifi"
                    ESSID:"rasp_garden_wifi2"
                    ESSID:"WIRE514"
                    ESSID:""

.:B:.

Forum Fellow

Registered: 2006-11-26

Posts: 5,819

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Re: Downgrade an 802.11n WiFi card to either b or g

There used to be a module parameter to lock the Broadcom card into 802.11g mode, but modinfo doesn't show anything anymore here (3.2.13 kernel).

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Strike0

Member

From: Germany

Registered: 2011-09-05

Posts: 1,491

Re: Downgrade an 802.11n WiFi card to either b or g

Does anyone have any idea why I can see so few networks with my on-board wireless card?

maybe your on-board antennae is bad/broken or your driver for wlan1 interferes with brmsmac.

LetSleepingKidsLie

Member

Registered: 2011-03-09

Posts: 4

Re: Downgrade an 802.11n WiFi card to either b or g

The hardware works (it runs fine under Windows). I also don't see any other networks when I don't have the USB WiFi adapter (wlan1).

My current thought is that it is not seeing the other networks because their signal strengths are below some threshold value. It sees the router that is in the same room, but it is not seeing any other networks in the area.

Does anyone know if there are settings to decrease the signal threshold on the brcmsmac driver to ensure that it doesn't discard these other networks as noise?

Strike0

Member

From: Germany

Registered: 2011-09-05

Posts: 1,491

Re: Downgrade an 802.11n WiFi card to either b or g

Have a look at the iwconfig manpage for that.
Maybe you should try if another driver (e.g. b43) works better for your internal card (whichever that is).