At one point, on another device, I also had slower speeds using a USB device as a second radio. Someone suggested that putting the USB radio on an extension cable would improve the speed, which implied some type of interference. Ultimately I replaced the USB with one that had a larger antenna. It improved the speed, but it was not as good as the single radio.
Just to be clear, link speed is not a speed test. Your link speed is also dependent on the STAtion\client you are connecting to, as well as the channel width for your MT300A. You may also have different link speeds for each radio or connection. There is also an up and a down link speed, for a total of 4 values.
Use the Advanced Config (Luci) and go to Network=>Wireless. Choose Edit for one of the wireless connections. (One will say linked to …, use the other). Set the channel width to 40 from 20, if it’s not. The devices at the other end should have similar configurations to get the best “link speeds”, or the MT300A will run at the lower of the 2 speeds (at best). Link speed will probably fluctuate.
for using 2 APs on 2.4GHz these are expected results. i would suggest to get atheros device like tp-link TL-MR22U because ar150 is crap and i wouldn’t expect much more from ar300 too, and run it’s wifi on 2.312GHz, then you will get good speed with rt3070 on any of the 1-13 channels. otherwise be happy with 5-10Mbps speed.
I understand link speed vs speed test. I was just making a side comment about the router performance itself while in a normal application. At this point I’m going to try a different openWRT device. I just ordered a D-Link DIR-860l . Thanks for all the feedback.
@psyborg, be nice! If you have problems you can solve with us. And we did ask you send us emails so that we can help. I think what you are saying is that AR150 can output more power in its USB-A port. Why that is a bad design? You are saying that it causes the router to boot because the external device is using too much power. But as USB2.0 specs the USB-A can only output 500mA. So is that enough to power up your USB device. You should also notice that a battery can output more current than a power adapter.