[Voyage-linux] Turbo mode

[bob]

Aloha Edwin,

Your timing is impeccable, as I just turned up a new system with Alix, 
Voyage 0.4.1, and wlm54ag.

In the past, I've puzzled over the turbo mode, but never investigated it 
to make it work.

I've found that iwpriv ath0 get_turbo returns 1, even though I haven't 
set it.

Iwconfig shows Turbo mode on specific channels, and 11a on other 
specific channels.  iwpriv ath0 turbo 1 does not appear to turn on turbo 
on non turbo channels, and iwpriv ath0 turbo 0 does not appear to turn 
off turbo mode.

So, my guess is that turbo mode is being controlled by the eeprom and 
channel selected.

I don't know if turbo mode is really on or not, even though iwconfig 
says it is, because the available rates are the same, turbo or not, and 
I have not noted (and not explicitly checked) throughtput.

I suspect that it is turbo mode, because it seems to require a slightly 
better rx signal to associate.

As a side note, I noted a couple of times, that a radio may not 
associate when the distance is set too short.  This is not always the 
case, because I usually set the dx after association and testing, but on 
two separate occasions now, I have found that setting the dx out beyond 
expected allowed for association.

You might try setting the rate to auto to see if they associate at a 
lower rate in turbo mode.

Hope this helps.
bob

Edwin Whitelaw wrote:
> I've been all over Google and the madwifi wiki, etc and have not found 
> the magic incantation to invoke turbo mode with madwifi/Voyage.  The 
> test setup at the moment is Voyage 0.4.1 on two shiny new ALIX boards.  
> Radios are CM9s, range is ~3.3mi (5280m).  Running in 802.11a mode
> 
> iwpriv ath0 turbo 1
> iwconfig ath0 rate 54M
> 
> Set Master end to one of the turbo channels and get no association.  Any 
> other channel links up right away.  I'm building an upgraded backhaul 
> into my network and the additional bandwidth would be most helpful.
> 
> If this doesn't work, is it a CM9 issue?  Madwifi?  Any other radios 
> that will do turbo in this setup?
> 
> TIA,
> 
> Edwin
>