Friday, April 10, 2020

Nice day for space birds

My lovely family got me an sdr dongle for christmas, and I had been itching to use it to receive weather satellite images.  But most of the discussions around it talk about building a somewhat fancy antenna, which I didn't really want to do.  So I started looking to see if I could use the rabbit ears that come with the kit, and turns out you can.  Following instructions here and here, I got decent results!


Couple of notes:

  • I started off measuring the VSWR with my NanoVNA.  I did as the instructions said (length/angle), and immediately got <1.5, so was happy there.
  • Had to restart computer (CubicSDR wasn't putting out sound), and had to switch my SDR back to *not* use direct sampling (I had it setup for HF stations).  Finally managed it to tune in an FM station.
  • I was using my compass on my iphone to point the antenna, and I noticed it thought north was very much the wrong direction.  Finally found that sometimes you have to do a funny "figure 8" motion with your phone to tell it to recalibrate the compass.  Weird.
  • I set wxtoimg to autorecord, and it started right on time.  However, the image was all black.  Eventually, played around in loopback turned up the "pass through" volume, and it started showing an image!  It had the same artifacts on the side that the blog had, too (not pictured above).  In any case, I should have calibrated from the start like the wxtoimg instructions said (but I don't think were in the blog entry).




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