LNA behaviour of the Nova-T 500 (was: Re: [linux-dvb] Preliminary support of Hauppauge Nova-T 500 Dual(take2))

Patrick Boettcher patrick.boettcher at desy.de
Wed Sep 20 08:51:48 CEST 2006

On Tue, 19 Sep 2006, Steven Toth wrote:
> > > In the windows driver we leave the LNA off at all times, but have a
> > > registry
> > > override to allow users to enable it. It's a single LNA for both tuners -
> > > hence, it has its problems.
> > >
> > > Switching the LNA dynamically in a TV app isn't something the API allows.
> > > How
> > > about a module load param?
> > >     
> >
> > As updating an LNA (or something else) is very board specific, I put
> > callback "update_lna" in dib3000mc_config. I will call this after starting
> > the AGCs to see if the LNA has to be turned on or not (taking the agc
> > response into account). For that I would like to know, what is the gain of
> > the LNA when turned on? (So that I can adjust the thresholds when to turn on
> > or off). Maybe we need to make an average of both channels, not that we kill
> > one channel by only taking the other one into account. 
> >
> > Or is a module_parameter enough? (I don't like this, because the majority of
> > users does not even now what is a module, which is good).
> >   
> Image a user that lives somewhere between two broadcast towers. They receive
> some muxes at fairly weak levels and some very strong (environment depending).
> We never found a good automatic solution to deal with that within the
> (windows) driver.
> If the driver can be made to work reliably for all users in Linux under all
> circumstances then that's ideal. :)

I can live with a module paramter and turning it off by default. IMHO, it 
was not a good decision to put only one LNA for both tuners ;).

OK will do so and document it in the Wiki.

Thanks for the input,

PS: If we find an automatic solution later, the better.

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