ADSL: upstream speed higher than downstream

My brother has a very poor connection - 140kb downstream according to the BT speed test.

The upstream speed however is reported as >400kb.

This seems very strange to me but on the phone, BT seem to think its normal.

Can anyone explain to me why the download speed would be so awful while upload remains pretty good?

Upstream uses lower frequencies than downstream and is less susceptible to interference.

http://en.wikipedia.org/wiki/File:ADSL_frequency_pla...

Nah, probably because the connection is soo unstable that the IP profile has been knocked right down

what is the connection speed shown by the router or by speedtester.bt.com (as opposed to a speed test result)