brainwagon

Well, I’ve been experimenting a bit more with some weather satellite reception, and on the off chance that anyone cares, I thought I’d write down some of what I learned. Last night (after dark) I decided to record an NOAA-17 pass. This time, I used my Yaesu VX-3R, which has a wideband FM setting, and my totally inappropriate Arrow Yagi that I have been using for satellite reception. I recorded the pass using a little Sony voice recorder. This was my result:

Bigger version, recorded with the Sony Voice Recorder…

It was during the dark, so I didn’t really expect to see much detail, but I noticed lots and lots of horizontal streaking. A moment’s thought made me realize that it was probably because the voice recorder compresses the audio, resulting in these short term artifacts. So, this morning, I lugged my laptop out into the yard and recorded some pristine, uncompressed audio. Here’s the result:

Full Size Version, recorded on my laptop…

What have I learned? That with a gain antenna that tracks, and the wideband fm setting, you can probably record some pretty reasonable images. Yes, it’s suboptimal: you get more noise in the image than the approrpriate bandwidth would allow. But still, they aren’t too bad.

I’m gonna work on improving my decoder some (45 lines of code really isn’t enough), and then maybe work on this some more when I’m on my christmas break.

Addendum: Sadly, when I tried to record a pass of NOAA18 over the ocean, I found another difficulty: intermodulation interference. I could hear a strong local FM station, and what sounded like aircraft audio superimposed with the satellite downlink. The results were far from stellar.

Ugly NOAA18 Pass, lots of interference…

Addendum²: A pass of NOAA-15 was happening just as sunset, and was going to be east of my position. Unfortunately, just as it was getting interesting, it shifted to a different mode or something, and I lost the super-cool looking grazing earth. But I did find that there are some places where perhaps I’m not as directly blasted by all the many sources of interference that I heard in the previous pass, so the overall pass is somewhat less noisy.

The full image from NOAA-15.