Packet loss on WLAN

[sadmax]

Hi!

I am having problems with Asus WL500g wireless router. I set it up two weeks ago and it worked fine, but now I am getting 1-5% packet loss for last five days. This happens approximately every minute once for about a second or two. It looks like setting floods the network every minute or something like that. I already tried to change antennas, block all net-using-programs on wireless computers but nothing helps. I also figured out, that if I use computer near the router, I get high ping instead of packetloss.

1 m away from the router:
...
Reply from 192.168.0.10: bytes=32 time=1ms TTL=64
Reply from 192.168.0.10: bytes=32 time=1ms TTL=64
Reply from 192.168.0.10: bytes=32 time=130ms TTL=64 <- every 50-70. ping
Reply from 192.168.0.10: bytes=32 time=1ms TTL=64
...

15 m away from the router:

...
Reply from 192.168.0.10: bytes=32 time=1ms TTL=64
Reply from 192.168.0.10: bytes=32 time=1ms TTL=64
Reply from 192.168.0.10: bytes=32 time=439ms TTL=64 <- every 50-70. ping
Reply from 192.168.0.10: bytes=32 time=1ms TTL=64
...

60 m away from the router:

...
Reply from 192.168.0.10: bytes=32 time=1ms TTL=64
Reply from 192.168.0.10: bytes=32 time=1ms TTL=64
Request timed out. <- every 50-70. ping
Reply from 192.168.0.10: bytes=32 time=1ms TTL=64
...

I dont know, what could I set wrong. What is the cause of this delay?

Thank you for any help

Gašper