hostapd bit rate setting, Rate not more than 18Mb by a signal of -42dbm ...

[Beat Meier]

Hello

How can I set bitrate at startup of hostapd?

If I set after running hostap with
  iwconfig ath0 bit 6M
iwlist ath0 bit tells me
  Current Bit Rate=6 Mb/s
iwconfig ath0 tells me
  Bit Rate=6 Mb/s
but client wpa_supplicant has rate 48Mb

If I set 48M for example of client and server
ping doesn't work. I have a signal of -42dbm.

If rate is auto the bitrate of client is 18Mb
I have no noise (-95) and signal of -42.

Why does the rate not go higher that 18M?

Power issues of madwifi, ok let it be ... nothing changes if 6Mb set or 
54Mb set ...

Any infos

Beat