Re: [Discuss-gnuradio] DBS Dish Feeds

[Marcus Leech]

Matt Ettus wrote:

> DBS small satellite dish systems often have LNB feedhorns capable of
> multiple polarizations and/or multiple bands.  This is often controlled
> by changing the voltage which powers the device.  However, some have a
> more complex control system involving tones in the 20kHz range if my
> memory serves correctly.  Is there anyone who has a reference on this
> control system, or who knows how it works?  I want to use these for
> radio astronomy with the USRP and need to know how to control them.
>
> Thanks,
> Matt
>
>  
Polarization is selected either using LNB voltage level (13V and 17V are 
typical thresholds), or
 using DiSEQC, which is a 22Khz digital code that can be used to 
control feed parameters
 and also control any mechanical arm on the dish, and also change LO 
frequencies on
 the LNBF

The specification can be had here:

http://www.eutelsat.org/satellites/4_5_5.html

Maxim also has an app note or two about interfacing to DiSEQC equipment