Problem with 5 GHz wifi site in MBA mid 2012

Question

Level 1

19 points

Problem with 5 GHz wifi site in MBA mid 2012

Hi. I am sorry for me bad english...

I have problem with 5 GHz wifi on me MBA 13 mid 2012. This not see 5GHz site . But all me olders macs - iMac 2010 and MBP 2011 see this and working on this site without none problems. And all our iPads and iPhones also working on this perfect without problems.

I think, so problem is in support of wifi channels in MBA. All others and olders me macs support according his system info channels 1-13 for 2,4 GHz and 36-48 for 5 GHz also, but MB Air support channels 1-13 only , NOT 36-48 for 5GHz. Therefore MBA not see this 5 GHz site.

I see according to others discussions, so this problems have much others customers, and any in other macbooks also, not on Air only...And minimum 2 years !!! But none know fix of this problem . Apple not see this problem ???

Do you know any really fix and solve of this ? I thinking about return of this MBA to Apple,but I am afraid a little, so in any new will be the same problem...

Posted on Sep 9, 2013 2:27 PM

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Answer 1

Linc Davis

Level 10

209,547 points

Sep 9, 2013 7:06 PM in response to Jirka Dytrt

Back up all data before making any changes.

Step 1

Take all the applicable steps in this support article.

Step 2

If you're running OS X 10.8.4 or later, run Wireless Diagnostics and take the remedial steps suggested in the summary that appears, if any. The program also generates a large file of information about your system, which would be used by Apple Engineering in case of a support incident. Don't post the contents here.

Step 3

If you're not using a wireless keyboard or trackpad, disable Bluetooth by selecting Turn Bluetooth Off from the menu with the Bluetooth icon. If you don't have that menu, open the Bluetooth preference pane in System Preferences and check the box marked Show Bluetooth in menu bar. Test. Continue if you find that Wi-Fi is faster with Bluetooth disabled.

From that same menu, select Open Bluetooth Preferences. If the box labeled Discoverable is checked, uncheck it. Click the Advanced button, and in the sheet that opens, uncheck the top three boxes, if any are checked. Click OK. Enable Bluetooth and test again.

If the application called "Bluetooth Setup Assistant" is running, quit it.

Step 4

This step will erase all your settings in the Network preference pane. Make a note of them before you begin, and recreate them afterwards. It may be helpful to take screenshots of the preference pane.

Triple-click the line below on this page to select it:

/Library/Preferences/SystemConfiguration

Right-click or control-click the highlighted line and select

Services ▹ Reveal

from the contextual menu.* A folder should open with an item named "SystemConfiguration" selected. Move the selected item to the Trash. You may be prompted for your administrator password.

*If you don't see the contextual menu item, copy the selected text to the Clipboard (command-C). In the Finder, select

Go ▹ Go to Folder...

from the menu bar, paste into the box that opens (command-V). You won't see what you pasted because a line break is included. Press return.

Reset the System Management Controller.

Step 5

Make a "Genius" appointment at an Apple Store, or go to another authorized service center.

Back up all data on the internal drive(s) before you hand over your computer to anyone. There are ways to back up a computer that isn't fully functional — ask if you need guidance.

If privacy is a concern, erase the data partition(s) with the option to write zeros* (do this only if you have at least two complete, independent backups, and you know how to restore to an empty drive from any of them.) Don’t erase the recovery partition, if present.

Keeping your confidential data secure during hardware repair

*An SSD doesn't need to be zeroed.

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Answer 2

Jirka Dytrt Author

Level 1

19 points

Sep 10, 2013 1:36 AM in response to Linc Davis

Thank you, but this is not solve of this problem. I was try all this steps, but MBA not see 5GHz site always.

After trash of SystemConfigurations is this site in list, but is inaccessible and after 10-15 seconds disappear from this list. I think, so problem is in support of channels in MBA System profile . iMac and others macs supports channels nr : 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 . but MBA support this only - 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13. And as you know, that 5GHZ channels are 36, 40, 44, 48 . According to this MBA not support channels for 5 GHz and therefore are this problems, I think.

I was contact Apple technical support , but they not help me and recommend me solve this with dealers in our country and try exchange of this . But I am afraid a little, so in any new MBA will be the same problem, because I see in various discussions , so this problems have much customers. And not with MBA only...

I send MBA to dealer for complaint and now I use old iMac, which support this 5 GHz channels without none problems. And I will see, if Apple solve this problem or if give me new MBA. But in this case I will control in his system profile, if this support 5 GHz channels 36,40,44 and 48 .

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