[linux-dvb] How to switch power supply for active antennas?

[Johannes Stezenbach]

Sebastian Schneider wrote:
> I got a Technisat Airstar 2 DVB-T PCI Card running in my PII 400 MMX 
> with kernel 2.6.10 and vdr 1.3.17 together with the dxr3-plugin 0.2.3-pre2.
> 
> Here's my problem:
> I measured 5V DC on the antenna input of my Airstar 2, which makes me 
> believe that it is configured for the use with an active antenna. As I 
> read, active antennas can lead to worse quality if they are used in 
> regions where the signal strength is quite strong enough for passive 
> antennas. So I got a passive one, but now I have to turn the 5V DC off.
> I'm studying computer science so i'm a bit experienced in programming. I 
> - of course - searched the internet and looked in/changed various kernel 
> modules (skystar2, mt315, mt352, stv0299) but didn't manage to turn it 
> off. I read parts of the DVB-API documentation as well, but all I found 
> were functions concerning the power of LNBs.
> 
> Could someone tell me how to turn the 5V DC off? Is it even possible?

I am not sure if it can be turned off, but I am quite sure
that it isn't necessary to turn it off to use a passive antenna.

Johannes