RSSI Very low Every 1 week

MicroLan

$ ifconfig -v ath0
ath0: flags=8943 <up,broadcast,running,promisc,simplex,multicast>mtu 1500
inet6 fe80::202:6fff:fe3f:3c29%ath0 prefixlen 64 scopeid 0x3
ether 00:02:6f:3f:3c:29
media: IEEE 802.11 Wireless Ethernet autoselect mode 11b <hostap>status: associated
ssid wireless channel 6 (2437) bssid 00:02:6f:3f:3c:29
authmode OPEN privacy OFF deftxkey UNDEF powersavemode OFF
powersavesleep 100 txpowmax 38 txpower 63 rtsthreshold 2346 mcastrate 1
fragthreshold 2346 -pureg protmode OFF -wme burst ssid SHOW -apbridge
dtimperiod 1 bintval 100

WARP: 1 LAN 1 WAN
MINIPCI: senao 8602 400 mw

MINIPCI senao 8602 de 400 mw the signal is very very very low

ADDR AID CHAN RATE RSSI IDLE TXSEQ RXSEQ CAPS ERP
00:0e:2e:42:b9:f3 1 6 11M 10 135 35705 65392 ES 0
00:02:72:4c:b1:e6 5 6 1M 8 195 58373 18640 ES 0
00:02:72:4c:ca:f0 6 6 1M 5 165 1757 17056 ES 0
00:0e:2e:55:3a:b5 10 6 11M 12 120 51886 59360 ES 0
00:0d:87:d8:c9:20 18 6 11M 3 255 29841 15472 ES 0

That it are bad? please help me

This happens 1 time a week every Wednesday ???

Then I reinstall it and it walks well ???</hostap></up,broadcast,running,promisc,simplex,multicast>