Weather Satellite Script Help (Raspbian)

Discussion in 'Satellite and Space Communications' started by K3RLD, May 31, 2018.

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  1. KD0KZE

    KD0KZE Ham Member QRZ Page

    This looks like a pretty nifty project. I used to write some stuff in bash awhile back, but I think I'd port this over to Python. It's quite powerful and much cleaner to look at (and therefore easier to debug, IMHO). I haven't taken the plunge with a Raspberry Pi yet, but this looks like a great way to get one's feet wet.
     
  2. K3RLD

    K3RLD Ham Member QRZ Page

    Yes, it will work. And yes, raspbian ships with a built in (and free) VNC server. Not sure if it's compatible with Putty, but the VNC client is free for all operating systems. I installed it on my work windows machine and connect to both my home pi's (well, actually I can only connect to one pi, due to port forwarding, but then I can VNC into the other one from the first one). I believe you will, however, have to connect a monitor when first starting to enable VNC/SSH/etc. But the good news is the pi comes with HDMI as standard, so just hook it up to your TV for the setup, and then SSH/VNC for everything else.

    As for python, I agree. I'm in the process of learning python myself. This seems like the perfect first project (converting to python, that is).
     
    KA2CZU and WD9EWK like this.
  3. KA9JLM

    KA9JLM Ham Member QRZ Page

    I took the pi plunge, But only have 4 RPi3B models. I want a +

    These little computers are as addicting as heroin. :eek:

    You should seek help if you get a addiction.

    Have Fun.
     
    K3RLD likes this.
  4. KK4PP

    KK4PP Ham Member QRZ Page

    This project has me intrigued. My home brew eggbeater has been sitting on the roof unused for months since the ISS digipeater went down. Any thoughts on how it would work? It’s circularly polarized, but resonant 10 MHz higher than the NOAA frequencies.
     
  5. K3RLD

    K3RLD Ham Member QRZ Page

    Well, the NOAA are circularly polarized (RHCP, I believe), so I think you should actually do better than my terrible images. Give it a whirl.

    EDIT: I forgot to mention that I am using a vertically polarized 3/4 wave groundplane antenna resonant on 145.825, with no LNA. And it's attic mounted.
     
  6. KK4PP

    KK4PP Ham Member QRZ Page

    Roy, did you ever get the bugs worked out of your project? I finally put mine together this weekend using my home-brew eggbeater. The scripts are working well and I am very pleased with the results. Attached are a couple images...


    NOAA1820180710-211236.MCIR.png


    NOAA1920180709-170915.MCIR.png
     
  7. K3RLD

    K3RLD Ham Member QRZ Page

    Yep, but only get decent results on NOAA 19. How do you get the color? I know it has something to do with using old keys and adjusting clocks or something.... or is there an easier way?

    [​IMG]
     
  8. KK4PP

    KK4PP Ham Member QRZ Page

    Wxtoimg has the ability to apply filters to your images. They make all the difference. Edit these lines into your Receive_and_Process_Satellite.sh file in your Predict folder. You should have most of them. Just add the lines you don't already have.

    if [ -e $3.wav ]
    then
    /usr/local/bin/wxmap -T "${1}" -H $4 -p 0 -l 0 -o $PassStart ${3}-map.png

    /usr/local/bin/wxtoimg -m ${3}-map.png -c -e ZA $3.wav $3.png
    # /usr/local/bin/wxtoimg -m ${3}-map.png -c -e NO $3.wav ${3}.NO.png
    /usr/local/bin/wxtoimg -m ${3}-map.png -c -e MCIR $3.wav ${3}.MCIR.png
    /usr/local/bin/wxtoimg -m ${3}-map.png -c -e MSA $3.wav ${3}.MSA.png
    # /usr/local/bin/wxtoimg -m ${3}-map.png -c -e HVCT $3.wav $3.HVCT.png
    # /usr/local/bin/wxtoimg -m ${3}-map.png -c -e therm $3.wav $3.Thermal.png
    # /usr/local/bin/wxtoimg -m ${3}-map.png -c -e JF $3.wav $3.JF.png
    fi

    If you uncomment (remove the #'s) all the lines, each line will produce an additional image. Pick the images you like the best, and then comment out the rest. Personally, I have found the ones ending in MCIR and MSA to be the best. I commented out the rest to get rid of them.
     
    K3RLD likes this.
  9. KK4PP

    KK4PP Ham Member QRZ Page

    Have you played around with the gain settings in your rtl_fm line? I noticed that you previously posted that you were using:

    rtl_fm -f 137620000 -s 11025 -g 29 -p 22 - | sox -t raw -e signed -c 1 -b 16 -r 11025 - recording.wav


    Try changing the "-g 29" to "-g 49.6" to set the gain to max.

    In my case, I eliminated the "-g 29" entirely which lets the rtl software refault to auto gain. That gives me the best results.
     
    K3RLD likes this.
  10. K3RLD

    K3RLD Ham Member QRZ Page

    Actually, gain is currently set to -48. I'll try removing it completely, though.
     

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