[Voyage-linux] RSSI different depending on which command used

[bob]

Aloha,

"21:91 : Quality=16/94  Signal level=-68 dBm  Noise level=-84 dBm "

May I suggest noise of 11db on ch161 + signal of 16db = 27db or -68dbm 
'Signal Level'? and the noise isn't included/excluded in the other commands.

I take all these readings with a grain of salt, since they're 
averaged/weighted over time.  Scan's often seem to show peak signal 
level rather than average, and often persist long after the signal is 
gone; (with my older version madwifi)

Once I have a connection, i use wlanconfig ath0 list to peak the antenna.

When I see the link in wlanconfig ath0 list, but have no throughput, it 
seems to indicate that the s/n is not sufficient on the far end, usually 
due to noise/interference.


If ld-tr6 is not local, you may wish to associate with it, and verify 
your erp from local.  Also, if ld-tr6 is not local, the high rx level 
and high directivity of your antenna suggests that you're pointed pretty 
much directly at it?

Hope this helps;
bob


Edwin Whitelaw wrote:
> I'm working on an 18.5 mi link using 2 WRAPs with the Ubiquiti 600mw 
> cards.  Obviously, antenna aiming is critical and difficult so the RSSI 
> is an important tool to get things working.
> 
> Note the RSSI/SN for "ld-peak" as reported by the different commands run 
> on the managed end.
> 
> --------------
> ld-peak:~# wlanconfig ath0 list
> ADDR               AID CHAN RATE RSSI  DBM IDLE  TXSEQ  RXSEQ CAPS ACAPS 
> ERP             STATE     MODE
> 00:15:6d:63:21:91    0  161   6M   16  -79    0  11866  29024 Es   
> F       0                 0   Normal WME ATH
> ld-peak:~# wlanconfig ath0 list scan
> SSID            BSSID              CHAN RATE  S:N   INT CAPS
> ld-tr6          00:60:b3:c5:ca:3d   64   54M 50:0   100 EP
> ld-heritage     00:0b:6b:4e:29:a5   36   54M 42:0   100 EPs  WME ATH
> ld-buffalo      00:0b:6b:4e:2a:25   40   54M 33:0   100 EPs  WME ATH
> ld-schaeffer    00:0b:6b:36:ba:e9   44   54M 41:0   100 EPs  WME ATH
> ld-reilly       00:0b:6b:4e:2a:52  149   54M 32:0   100 EPs  WME ATH
> ld-peak         00:15:6d:63:21:91  161   54M 16:0   100 Es   WME ATH
> ld-peak:~# iwconfig ath0
> ath0      IEEE 802.11a  ESSID:"ld-peak"  Nickname:""
>          Mode:Managed  Frequency:5.805 GHz  Access Point: Not-Associated
>          Bit Rate:6 Mb/s   Tx-Power:16 dBm   Sensitivity=0/3
>          Retry:off   RTS thr:off   Fragment thr:off
>          Encryption key:off
>          Power Management:off
>          Link Quality=16/94  Signal level=-68 dBm  Noise level=-84 dBm
>          Rx invalid nwid:0  Rx invalid crypt:0  Rx invalid frag:0
>          Tx excessive retries:0  Invalid misc:0   Missed beacon:0
> 
> ld-peak:~# iwspy ath0 00:15:6d:63:21:91
> ld-peak:~# iwspy ath0
> ath0      Statistics collected:
>    00:15:6D:63:21:91 : Quality=16/94  Signal level=-68 dBm  Noise 
> level=-84 dBm
>    Link/Cell/AP      : Quality=15/94  Signal level=-69 dBm  Noise 
> level=-84 dBm
>    Typical/Reference : Quality:0  Signal level:0  Noise level:0
> -----------
> 
> Any comments on understanding why wlanconfig reports only -79db while 
> iwconfig and iwspy report a lovely -68db?  If it really is -68db, I 
> would expect association at excellent bit rates that's not happening.
> 
> Also, as indicated from iwconfig, the link does not associate.  I do 
> have athctrl set correctly for the distance.
> 
> ----/etc/network/interfaces---
> auto ath0
> iface ath0 inet static
>        address 10.100.1.1
>        netmask 255.255.255.0
>        broadcast 10.100.1.255
>        madwifi-base wifi0
>        wireless-mode Managed
>        wireless-essid ld-peak
>        wireless-channel 161
>        up athctrl -i wifi0 -d 29600
>        down wlanconfig ath0 destroy
> ---------------
> 
> Thanks,
> 
> Edwin
> 
> PS.  Anyone heard of the new ALIX boards for sale in the US, yet?
>