5GHz WiFi not working since upgrade on 2011 MBP

[MagicBoy]

Since the 10.8 upgrade my MBP can no longer see any 5GHz WiFI APs.

It worked just fine in 10.7, and the Mac mini running 10.6.8 can still connect to the 5GHz AP (Linksys WRT320N with all the routing and DHCP disabled) just fine. As soon as I reconfigure the AP for 2.4GHz then it starts working again on the MBP.

Anyone else have this problem?

 

[phyrexia]

I have an Early 2011 17" with ML. I have not yet experienced problems connecting to my 5ghz network. I own a Linksys E4200 running Tomato. The DHCP server is enabled.

Which channel is your 5ghz network set to?

Since the 10.8 upgrade my MBP can no longer see any 5GHz WiFI APs.

It worked just fine in 10.7, and the Mac mini running 10.6.8 can still connect to the 5GHz AP (Linksys WRT320N with all the routing and DHCP disabled) just fine. As soon as I reconfigure the AP for 2.4GHz then it starts working again on the MBP.

Anyone else have this problem?

 

[MagicBoy]

It's on Auto, has picked Channel 36.

 

[Wilson1313]

I have an Early 2011 17" with ML. I have not yet experienced problems connecting to my 5ghz network. I own a Linksys E4200 running Tomato. The DHCP server is enabled.

Which channel is your 5ghz network set to?

I have an e4200 running on the latest firmware, yet I have issues connecting to my 2012 MBA. It sometimes will just drop the connection (or just doesn't load the pages) until I disconnect/reconnect or restart the router. Not sure which is the problem...

 

[stevemiller]

ugh. i'm having a similar issue. when i bring my computer home at the end of the day, it occasionally can't see my 5ghz network for something like 5 minutes, then it suddenly appears. i guess its good in that it eventually shows up, but still annoying.

 

[MagicBoy]

Connected up a Firewire drive running 10.6.8 today on the affected MBP. It sees and connects to the 5GHz network fine so it's definitely not a hardware problem.

Tempted as I am to do a clean re-install of ML it's unlikely to happen at the moment.

Changing the channel hasn't helped. iStumbler isn't picking up any 5GHz networks period.

 

[MagicBoy]

Mystery solved after I went to look at the detailed stuff in System Information :

en1:
Card Type: AirPort Extreme (0x14E4, 0xD6)
Firmware Version: Broadcom BCM43xx 1.0 (5.106.98.81.20)
MAC Address: <redacted>
Locale: ETSI
Country Code: TW
Supported PHY Modes: 802.11 a/b/g/n
Supported Channels: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 56, 60, 64, 100, 104, 108, 112, 116, 120, 124, 128, 132, 136, 140, 149, 153, 157, 161, 165
Wake On Wireless: Supported
AirDrop: Supported
Status: Connected

Note the supported wireless channels - the 5GHz channels in the UK are 36-48 which are not on the list. A firmware upgrade on my router appears to have changed the country code. OS X detects this using 802.11d and enables what it believes are the correct channels.

Having disabled the WiFi on the router, OS X now sees the 5GHz network first and allocated the correct channels :

en1:
Card Type: AirPort Extreme (0x14E4, 0xD6)
Firmware Version: Broadcom BCM43xx 1.0 (5.106.98.81.20)
MAC Address: <redacted>
Locale: ETSI
Country Code: GB
Supported PHY Modes: 802.11 a/b/g/n
Supported Channels: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 36, 40, 44, 48, 52, 56, 60, 64, 100, 104, 108, 112, 116, 120, 124, 128, 132, 136, 140
Wake On Wireless: Supported
AirDrop: Supported
Status: Connected

Right, I'm off to shout at the router manufacturer...

 

[Supra James]

I have the same issue and came across your thread. My country code is also coming us as TW and not GB, and I can't see my 5GHz network any more.

Did you have any luck with Linksys? I'm running a WRT610N.