Comment 250 for bug 134660

Funny, this is what I had ready to post just while finding the above.

According to my tests, it seems to me that the problem is not that the interface is set to "rate 1M", but to "rate auto", and that this automatic bitrate adjustment mode is broken, setting rate down to 1M.
Hence, I have put this script in /etc/network/if-up.d under any name.

#!/bin/bash
# Only for wlanX...
[[ $IFACE == wlan* ]] || exit 0
iwconfig $IFACE rate 36M

to use a fixed bitrate. 54M is not necessarily the best value and you'll have to experiment, these were my rough results.

54M 140 KiBps
48M 170
36M 190
24M 180

It continues to be a mystery why the transmission rate is so low and still varies more than surrounding noise can explain (packet size adjustment? but that's sending side matter).
Anyway, doing away with having to compile the divers to continue each Ubuntu installation is excellent work.