Maybe you have been following, but my brother and I have been playing
with satellite reception using Digital TV dongles with modified drivers
to act as software defined radios.
Even though there are a lot of people who have done this already, and
there are many tutorials, they are incomplete. Lots of details need to
be pieced together to actually get a good setup.
Not to mention, the long hours tracking and waiting for satellites to
pass over, only to find out that of the 19 units in the sky, only 4 or 5
of them work!
Finally, after a several attempts, I was able to receive, record and process a pretty good pass, directly over Tucson!
Above was the raw downlink data after the radio signal was converted.
This is the processed image. For reference, I am including the official weather service images below, directly from their website at the time. You can visually match up the cloud bank off the coast of Baja California as a point of reference.
Now the fun stuff. We can process the images. The downlink includes an infrared channel on the left, and a visual channel on the right. Seeing as how the passover was at 3-4 am, the visual is not so exciting. We can see clouds, but landmass is hard to detect. No worries. The IR channel, combined with the fact that the decoder software has the satellite location means we can do all the overlays and other fancy stuff.
Below is a thermal image. This is comprised mostly of the IR channel, plus overlay.
Here we have another thermal image using the IR channel. This time, we are concentrating on the ocean. This allows the software to give us a lot more variation in color for a smaller range of temperature (or at least a range constrained to that of the ocean area on the map).

Finally, by combining the two images, and applying some false color, the software comes up with this 'daytime' image.
Note that I did no visual processing myself, other than select and save. The software is pretty smart and aware, provided the raw down-link is decent.
That’s sweet. We can take the images and use Processing or openFrameworks to do custom overlays, or perhaps overlay the weather data with other types of geographical or topological data. Should be fun to play with.
Akiba
FreakLabs Open Source Wireless
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Hey MRE,
So can we expect a class on SDR soon :)
You are right the topic is rather hot at the moment since people discovered they can use cheapish usb dangles.... Guess documentation efforts do not keep pace with the current progress.
Greetings
Totti
For satellites there is an android app too
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