I have a Ubiquiti XtremeRange2 Mini-PCI wireless-card. I use it in a desktop with a PCI-miniPCI converter.
It has a 600mW Output Power.
But
freeroute:/home/freeroute# iwlist ath1 txpower
ath1 8 available transmit-powers :
0 dBm (1 mW)
6 dBm (3 mW)
8 dBm (6 mW)
10 dBm (10 mW)
12 dBm (15 mW)
14 dBm (25 mW)
16 dBm (39 mW)
18 dBm (63 mW)
Current Tx-Power:18 dBm (63 mW)

So it is only 63 mW and not 600mW. How is it possible?

Have you any idea?

OS: Debian-lenny
Driver: madwifi
lspci -vv:
02:0d.0 Ethernet controller: Atheros Communications Inc. AR5413 802.11abg NIC (rev 01)
Subsystem: Device 0777:3002
Control: I/O- Mem+ BusMaster+ SpecCycle- MemWINV+ VGASnoop- ParErr- Stepping- SERR- FastB2B- DisINTx-
Status: Cap+ 66MHz- UDF- FastB2B+ ParErr- DEVSEL=medium >TAbort- <TAbort- <MAbort- >SERR- <PERR- INTx-
Latency: 96 (2500ns min, 7000ns max), Cache Line Size: 32 bytes
Interrupt: pin A routed to IRQ 11
Region 0: Memory at ec800000 (32-bit, non-prefetchable) [size=64K]
Capabilities: <access denied>
Kernel driver in use: ath_pci
Kernel modules: ath5k, ath_pci