Hi Martin.
Most modern satellite LNBs (Low Noise Block converters) have outputs in
the 950-1450MHz range. It varies a bit, but in that range is where you'd
look. If you do a bit of research you can probably find out what voltage
range your LNB requires and its output frequency based on the equipment
it was originally used with. Most LNBs use input voltage to select
antenna polarization and this control is provided by the original receiver.
As was mentioned, the DVB-S signal is 6MHz wide. I doubt you could
decode it with the bandwidth you can get from the DVB-T dongle. But I
seem to recall seeing DVB-S decoder boards for PC's starting around $30
on Ebay. You also would have trouble because in order to receive DVB-T
video, the dongle does some of the decoding in hardware. When we use
RTL-SDR drivers, we are bypassing the hardware inside the chip and
getting the raw data. My guess is that may be one reason that we seem to
be unable to achieve the full specified 3Mhz digitizing rate from the
chip's spec sheet.
An additional problem you haven't mentioned is the LNB itself. The Dish
Network and Direct TV satellites over the US use circular polarization,
the other services, including FTA (Free-To-Air) satellite signals, use
linear polarization. There are not many LNBs available that will receive
both types of signals.
If all you want to do is use the dongle to replace a $20 Sat-Finder,
then yes, you should be able to do it by simply looking at the waterfall
signal levels around 1000MHz as you adjust the antenna.
If you are thinking of decoding the actual satellite TV signals, you
haven't mentioned that most satellite video is from Pay-TV services and
is encrypted. So even if you have the correct LNB and have a DVB-S
receiver, the video is still digitally encrypted and you will not be
able to watch it. The exception is the FTA services which are broadcast
"in the clear" and some uplink remote video feeds.
For much more detail on the subject, you should search "FTA free to air
satellite" and all the associated web sites and wikis.
Good luck with your project.
Doug Reed, N0NAS.
"mr.sneezy" <
mr.s...@bigpond.com> Oct 16 04:34AM -0700 wrote:
> DVB-S signals via UC-SDR dongles ?