Tuning hostap configuration

[Paulo Sergio Lemes Queiroz]

Hi,

I'm having a strange problem with my network

Some times, some clients, get to lower tx rates.

Initially, I think its a channel problem... but when I change the 
channel, the tx_rate don't change.

I'm using this config:

IWCONFIG=/sbin/iwconfig
IFCE=wlan0
${IWCONFIG} ${IFCE} essid MyNet
${IWCONFIG} ${IFCE} nick  MyCard
${IWCONFIG} ${IFCE} mode  Master
${IWCONFIG} ${IFCE} rate  11M auto
${IWCONFIG} ${IFCE} frag  512
${IWCONFIG} ${IFCE} rts   65
${IWPRIV} ${IFCE} beacon_int 100
${IWPRIV} ${IFCE} dtim_period 20
${IWCONFIG} ${IFCE} channel 3
${IWPRIV} ${IFCE} prism2_param 30 1

Is anything wrong with config ?