Let me share a work around that has worked for me So far.
I Had an issue with my MacBook retina since I bought it last year and was not able to connect to 5Ghz high channels. Specifically on the 40mhz band, if I changed it to 20mhz it was fine, but half the speed for moving large data files around on my network. So I went back to the low channels like 44 but these frequencies don't pentrate my walls nearly as well and I have a week signal in the yard. The high channels I can walk 5 houses down and still get great speed.
Well the mac is in getting the wifi card replaced after this still was not fixed with yosimite, so I went back to the high channels at home. It's funny how all apple stores run Cisco wifi on high channels but only in 20mhz band or maybe they would see this issue also instead to recommend I buy a apple wifi router.
So today I picked up the iPhone 6 and nothing but issues on 5ghz. Tested 2.4 and seems stable. So then I changled the channle back from 157 to 44 amd now I'm finally able to complete a backup to the cloud without the wifi dropping. My iPad 2 mini retina is fine and the iPhone 5s seems fine on the high channels.
so I'm starting to think this is something again with high channels and 40mhz bandwidth.
oh before anyone mentions it yes I did all the standard scripting trouble shooting, resets, clean restores and bla bla bla.
So my request to all having issues is.
1. What channel are you running? If above 100 have you tried the lower end of the spectrum? If not can you and report back if it also helped you?
2. If your bandwidth on the channle is set to auto, or 40mhz can you try setting it to 20MHz and see if that helps and report back?
TiP some routers are able to run wireless N on 2.4Ghz and still uses the auto or 40Mhz bandwidth option in the setting. If your having these issues on a 2.4Ghz router try changing the bandwidth setting to 20Mhz like I did with the 5Ghz router. It might help you also. If it works please report back and let people know.
Im just looking for a pattern and sharing what helped me, then asking you to try and see if it helps you.
i Know, I know. This is not a fix. It's a temporary work around and apple still needs to fix this wifi stuff with the 5ghz range. It's a shame that great hardware and design is not starting to get a bad reputation just because of the software issues and not testing properly before releasing it.
if your reading this apple, it the mix of stable software, with hardware, simplicity and design that sells your product and was the reason I moved over years ago for that stable BSD kernel.i support enough to tech issues 70 hours a week and didn't want to deal with it at home. I admire the movement to bring everything together across all your hardware to be the same simplicity and the free OS updates for the Mac the last couple of years. But truth be told even junk unstable software is not worth being free. Please fire the guy responsible for this testing before release, and yes I have an idea on who this guys is also. Can you say apple maps?
