Wifi problems

Ok, again, but this time it isn’t going to be a rant, but rather description of my situation with request for help. :-)

We have a small wifi network (I am one of the two clients). We live very close, it’s only like 30-50m between me and the AP. The antennas can “see” each other. I use Intersil Prism 2.5 wavelan chipset. The AP is Draytek Vigor2006Ge.

It used to work, but lately my connection is really weird. It jumps between three states: no connection at all (there could be several reasons for it and it usually doesn’t last long anyway, so don’t bother), 100kbit and 3mbit (that’s what I want :-)). Weird thing is that “link quality” stays the same whether it’s 100kbit or 3mbit (it’s around 30-36 all the time). I test my connection with:

ping -s 1024 -c 1024 -f 10.0.0.138

1024 packets transmitted, 217 received, +35 duplicates, 78% packet loss, time 16021ms
rtt min/avg/max/mdev = 12.104/4771.567/6546.469/1548.455 ms, pipe 417, ipg/ewma 15.661/5394.273 ms

where -s is size of the packet, -c is number of packets and -f sends one after another very fast (and 10.0.0.138 is the IP of the AP ). When the connection is good I have 0% packet loss (usually one or two drop) and time 5000ms, it’s a big difference.
Another weird thing is that when I had no signal, no connection (yes, I was trying to connect to the correct AP all the time), I could see a lot of packets flying around. There were like 30-60 of them every second, all flying to 10.0.0.1, which is the other guy connected to the AP. Let me give you an example:

IP 147.230.151.63.11539 > 10.0.0.1.27390: . 187868:189270(1402) ack 1 win 65535

It’s probably DirectConnect, but that doesn’t really matter, the question is how comes I could see all those packets?

Here is some further information, but I doubt it will help anyone:

ifconfig
eth1 Link encap:Ethernet HWaddr 00:60:B3:6D:79:6F
inet addr:10.0.0.32 Bcast:10.0.0.255 Mask:255.255.255.0
inet6 addr: fe80::260:b3ff:fe6d:796f/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:782667 errors:343223 dropped:343223 overruns:0 frame:343216
TX packets:199530 errors:903 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:687827081 (655.9 MiB) TX bytes:34106034 (32.5 MiB)
Interrupt:11 Memory:df011000-df011fff

iwconfig
eth1 IEEE 802.11b ESSID:“mynet” Nickname:“zluty kopec”
Mode:Managed Frequency:2.467 GHz Access Point: 00:11:09:0E:51:33
Bit Rate:1 Mb/s Sensitivity:1/3
Retry min limit:8 RTS thr:off Fragment thr:off
Power Management:off
Link Quality=32/92 Signal level=-101 dBm Noise level=-149 dBm
Rx invalid nwid:0 Rx invalid crypt:14 Rx invalid frag:0
Tx excessive retries:1113 Invalid misc:0 Missed beacon:0

route
Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use Iface
10.0.0.0 * 255.255.255.0 U 0 0 0 eth1
default 10.0.0.138 0.0.0.0 UG 0 0 0 eth1

What totally puzzles me are the jumps. I’ve finally seen it yesterday, it jumped from link quality 0/92 to 34/92 in one second (I’ve got a script that does something like this: iwconfig | grep the relevant line, sleep a second). I probably needn’t mention that the jumps are not connected with any changes we make, it’s completely independent and seemingly random.

And how comes I have a very different connection speed (30 times lower) with the same signal quality?