Q: Airport Extreme Base Station as Extender to Airport Extreme Time Machine

Alright this thread got my interest since I started having some similar issues with my home setup and thought I would share my findings about extending wireless network with the new addition of a 6th Gen AExt .

First I have the following devices all with the latest firmwares (7.7.3 and 7.6.4).

2x AExt 5th gen

AExt 6th gen (AC)

AExp 1st gen (N)

AExp 2nd gen

I ran all my experiments alternating between 2.4GHz band (N) and 5GHz band (N). I only have a couple of devices using the AC band.

I have a wired ethernet network allowing me to run different tests.

Extending AExt 6th gen:

2.4GHz all the devices work.

5GHz band all work except for the AExt 5th Generation.

Extending AExt 5th gen

All devices work for both frequency bands.

Extending Aexp 1st gen. Since it is not bi-band and I had no interest in the 2.4GHz band I only tested at 5GHz.

All devices extend correctly. I did not test the AExt 6th gen as an extender to this device though.

Extending Aexp 2nd gen.

All devices work on both bands.

My devices never go crazy and drop connection like others have reported. When failure occurs, it just won't connect at all. The only devices which don't talk to one another are the AExt 6th and 5th gen when the 5th gen tries to join or extend the 6th gen in the 5GHz band. I am suspecting that it is due to the AC mode but why none of the other devices have this problem???

I was going nuts trying to get my AExt 5th generation to extend my network and could not understand why it would not work. I had my setup extend on 5GHz only and it would rather join one of my AExp which was already extending my network but with a low signal or an AExt 5th gen with an even lower signal. I ended up giving up and switching to the 2.4GHz network on that one Aext 5th gen which in turns expands on both bands. Of course I could just remove the specific name for the 5GHz band, I tried but it made no difference. The 5th gen Aext join the 6th gen only on the 2.4GHz band and all the other devices on the 5GHz band.

One alternative would be to flip the locations of the 5th and 6th gen AExt but I wanted the 6th to be on the wired network and the main unit at the center since it has the largest range...

The way the testing was conducted was under the following conditions for those who are interested:

I set my network by creating a wireless network with one name and then assigning a different name to the 5Ghz band. This gives me control over which band I will be joining/extending. I then set my extending device as either joining or extending a wireless network alternating between the 2.4GHz and the 5GHz network. My network is also access controlled and I have all my devices have one another's MAC addresses for both bands. All devices use WPA2 personal.

The AExt 6th gen (AC) has directional antennas and beam-forming. This seems to negatively impact extending the network. My experiments lead me to the conclusion that the AC unit (and all others in an environment which has one such unit) seem to be best served with a roaming network, where the Airports of all kinds are ethernet-connected in bridge mode to an upstream router. The AC caused more performance issues for me, than it addressed.

Any AC client, will switch to 802.11n in the absence of an AC access point. Gigabit wireless is nice but needs maturity and stability like 802.11n.

I would have to agree with you. As a total fluke, without changing any of the locations, I am now able to "beam" between the 5th gen and the AC at 5GHz.

How did I do it? I set my entire network to one name 2.4GHz and 5GHz except for the remote 5th gen unit. I asked for it to extend a network with a name which no other unit has and set the 5GHz with a name matching that of the rest of my network and... now it works. It forced the 5th gen to connect to the AC. It seems like the AC is now beaming towards the 5th gen... the result is also that my other remote bridged unit, an Aiport Express 2nd gen is going banana alternating between excellent signal and no signal at all. It seems like the 5th gen tries to extend network at 2.4GHz first but I can't explain why it would connect with my other 5th gen and airport expresses with a lower signal at both frequencies... It has to be this beam-forming from the AC not directing signal towards it.

About Wireless Diagnostics - Apple Support is a good tool to help analyze the environment and show performance at the RF layer as well.

Maybe I'm lucky considering the problems some have reported, but I just set up my AExt 5 to extend my network into the farthest reaches of my house using an ethernet cable connected to my primary AExt 6, with no issues - just plug and play. Both routers wee set up with identical network names and passwords; the only difference was that I set the AExt 5 to "bridge" mode.

Next I will test whether AirPlay will finally deliver signals to my Apple TV 3 without that dreadful audio and video stuttering it is famous for.  Otherwise, it's back to AirParrot 2 for me...