Here are the details you were wondering about...
Just to confirm, the are 100% line of sight.
In regestration it shows: tx/rx = 24Mbps/36Mbps Signal strength = -69
Why does a bandwidth test show that we get 4Mbps, while regestration sometimes show 48Mbps?
The MTU is currently 1500, we did try to play around with that.
Scans on the 5GHz band shows only 2 channels in use, we use one of them and there are 6 channels open, also rtied playing withthat.
The tx/rx CCQ = 67/00
Tx Signal = -70
Signal to noise = 21
Wireless cards used are the atheros AR5413 dual band cards (on 5GHz) with the tx power manually changed to 26dbm on both sides.
Anything else you need to know?