AP performance (again): txpower regulation

[Lev Serebryakov]

Hello, Freebsd-wireless.

 I return to experiments with my AP (FreeBSD based) again. I don't
attach new (802.11n-capable) card yet, as I cannot buy U.FL->RP-SMA
pigtails locally, but now I have two notebooks -- old Vayo and "new"
MacBook with KisMAC installed.

 I've checked theory (by Bernhard Schmidt), that my AP is TOO
powerful: set Vaio to run "iperf" forever, and monitor situation with
MacBook (KisMAC).

 iperf output (each 2 seconds) looks like this:

[  3] 70.0-72.0 sec  1.00 MBytes  4.19 Mbits/sec
[  3] 72.0-74.0 sec  1.12 MBytes  4.72 Mbits/sec
[  3] 74.0-76.0 sec  1.25 MBytes  5.24 Mbits/sec
[  3] 76.0-78.0 sec  1.00 MBytes  4.19 Mbits/sec
[  3] 78.0-80.0 sec  1.12 MBytes  4.72 Mbits/sec

ifconfig wlan0 list sta looks like

ADDR               AID CHAN RATE RSSI IDLE  TXSEQ  RXSEQ CAPS FLAG
00:18:de:08:e8:1d    2    9  11M 17.0    0  64411  15648 EPS  AQE     RSN WME
00:18:de:08:e8:1d    2    9  11M 18.0    0  64844  19088 EPS  AQE     RSN WME
00:18:de:08:e8:1d    2    9  11M 17.0    0  65283  22560 EPS  AQE     RSN WME
00:18:de:08:e8:1d    2    9  11M 17.5    0    169  25904 EPS  AQE     RSN WME
00:18:de:08:e8:1d    2    9  11M 16.5    0    668  29856 EPS  AQE     RSN WME
00:18:de:08:e8:1d    2    9  11M 17.0    0   1120  33440 EPS  AQE     RSN WME


 KisMAC (with Macbook placed near to Vaio) shows oscillation of signal power from 40 no 0 back and forth,
more "0" than "40" with average about 37. I don't know, is these
zeroes meaningful, or it is result of channel hopping.

 I've tried to set "txpower" from 1 to 30 (1, 5, 10, 15, 30) and wait
for 1 minute between settings. NOTHING CHANGES AT ALL. It seems, that
txpower doesn't work on my hardware :(

 My next experiment is to boot 9.0-BETA1 on my AP.

Hardware is:
Senao EMP 8602 Plus-S Mini-PCI WiFi card. It is Atheros
5413 based 600mW card:

ath0: <Atheros 5413> mem 0xa0060000-0xa006ffff irq 15 at device 17.0 on pci0
ath0: [ITHREAD]
ath0: AR5413 mac 10.4 RF5413 phy 6.1

10dBi omni antenna.
-- 
// Black Lion AKA Lev Serebryakov <lev at serebryakov.spb.ru>