From: "Frank Haber" 

1. What JB said: try another computer.  And please indicate whether it's a
true drop by your computer, or the access point's dropping the link to the
ISP?  PPPoE?  Do they use that in Europe?

2. Try another channel.  A radio is still a radio, and the laws of
physics.....  Perhaps someone's stomping on 6.  You may be experiencing
"the Tragedy of the Commons," which is demonstrated on WiFi a
thousand times a day around here, just on my block (city and subnet both)! 
BTW, is the AP 811B or G or mimo or proprietary?

3. Heat? Play a fan on the AP.

4. Microwave, wireless phone, etc. interfering.  Hi, grandma, wanna listen
to what happens when I kick everyone in the building off the net haha?

5. Run a 30m CAT5, and appease the gods for good.

--- BBBS/NT v4.01 Flag-5