It may be possible the where you have the AX located may just be in a spot where it does not get a good signal even it is only 8 feet away.
I suggest that you download and install iStumbler. You will use it to determine the signal quality by making Signal-to-Noise Ratio (SNR) measurements. This will be easiest if your Mac is a laptop ... or you can borrow one. When taking the measurements, you only want your "main" AirPort running as this is what we want to measure at the location of the AX.
SNR (in dB) = Signal (in dBm) - Noise (in dBm)
You can easily find the Signal and Noise value using System Profiler on your Mac laptop.
ref: Click on the Apple icon on the menu bar > About This Mac > More Info... > Contents > Network > AirPort > Interfaces > en1 > Current Network Information > Find your wireless network > Signal / Noise
While your still in the System Profiler, note the value for Transmit Rate.
These values should be negative numbers. For example, mine currently read: -67 dBm / -95 dBm, with a transmit rate of 27 (Mbps). Plugging in these numbers yield: SNR = -67 - (-95) = 28. My Mac Mini is about four rooms away from my AEBS with about five walls between them. As you can see, the signal is still quite useable ... but the bandwidth is minimal, especially for streaming.
SNR Guideline
- 40dB+ SNR = Excellent signal
- 25dB to 40dB SNR = Very good signal
- 15dB to 25dB SNR = Low signal
- 10dB to 15dB SNR = Very low signal
- 5dB to 10dB SNR = No signal
Please post back your results.