Help with odd home wifi network problem??

[Jedi5]

I'm a loss here and need some expert advice...

I have my Airport Extreme (tower) located in my basement office.
That gives the basement and main floor great wifi.

On the 2nd floor our wifi weakens.
So I connected via ethernet a spare 2nd gen Extreme to the 2nd floor to help extend the wifi signal.
Everything works great except one room get a really really bad signal.

Spare extreme is located in master room.
Down the hallway we have 3 bedrooms.
2 bedrooms on the right side of the hallway get great strong signal.
1 bedroom on the left side of the hallway gets poor signal.

The furthest bedroom on the right side gets good wifi while the closer bedroom
on the left gets crappy wifi.

Why would this happen?
Any ideas?

I was thinking of connecting a spare Express using ethernet to increase the signal.

Thoughts?

 

[chown33]

...
Why would this happen?
Any ideas?
...

Could be something in the wall (or walls). For example, something metallic in an unexpected location. It doesn't even need to be obviously metallic, like a steel door, or re-bar, or a wire mesh. It could be something made out of a metallic foil, such as fiberglass insulation batts, or something that doesn't even seem to be metallic but has a conductive internal layer sandwiched between layers that don't look metallic.

Could be something outside the exterior wall, like a next-door neighbor on the same wifi channel, causing interference.

Could be the bedroom with the poor signal is seeing some signal from the wifi in the basement, so receivers in that room can't decide which access point to use (the Basement one or the Spare one). You could turn off the Spare one and see what the signal looks like in that room.

Could be something behind the Spare Extreme in master room, that's causing the transmission pattern to be more beam-like than circular. In other words, the 2 bedrooms that get great signal are in the beam, but the one on the other side of the hallway isn't.

Each "Could be" is speculative, but I've encountered every one of them in real life, in different situations. The hardest one was a "dead room" that had been insulated for sound-proofing using fiberglass batts that had foil on one side. It was basically an unintentional Faraday cage.

Try moving the Spare Extreme out into the hallway temporarily, and see if anything changes. If all the rooms get good signal, try moving it straight up, into the attic (if you have one).


Wireless Diagnostics (10.8.4+)
http://support.apple.com/en-us/HT202663

Use Utilities window, Performance pane, Quality or Signal graph. Run it on a laptop, and stand in different places in different rooms.


What wifi channels are the 2 Extreme's on?

Are there other access points on the same channels that aren't part of your network?