site-posts/Intro to weather satellites.html

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<p>Early in quarantine I saw <a href="https://www.youtube.com/watch?v=cjClTnZ4Xh4">
this wonderful video</a> on how to grab images from satellites, and I was super
interested in the idea. The idea is that there are satellites called NOAA-15,
NOAA-18, and NOAA-19 that orbit the earth roughly every 102 minutes. They are
broadcasting through their entire journey and anyone can listen in and receive
images of earth that they are broadcasting.</p>

<p>The biggest problem is getting the images where I live (the suburb). There
is just so much <i>stuff</i> in the way to block the signal. Compared to other
satellites, its signal is pretty strong, but still not strong enough to go
through the concrete jungle. Therefore, I did a few months of research into how
to get a good signal from where I am. And thankfully, alot of people have
gotten good results with easy to make/buy antennas. I chose to buy a dipole kit
off of amazon to start, then attempted (but failed) to build a cross dipole out
of stuff from Home Depot, and some printed parts.</p>

<p>The other tools required were pretty easy to source (for me at least). The
hardest one would be the SDR, however I already owned a HackRF, so that was
pretty easy. If you don't have one already I would just get a RTL-SDR, they're
only 30 bucks and operate on a pretty solid range of frequencies. They also
have the biggest aftermarket support out of any of the SDRs I have seen.</p>

<p>Beyond those two and the miscellaneous bits (SMA/Coax, places to mount the
antenna, measuring tape, etc), all you need is the right software. I used
CubicSDR to receive the talk with the SDR
because it was simple and worked with the HackRF out of the box (at least on
windows), and WXtoIMG to convert the audio to an actual image.</p>

<p>So more of the technical details:</p>
<ul>
    <li>NOAA-19
        <ul>
            <li>Broadcast  : 137.1  Mhz</li>
            <li>Bandwidth  : 37.5   Khz</li>
            <li>Period     : 102    Mins</li>
            <li>Inclination: 98.7   Deg</li>
        </ul>
    </li>
    <li>NOAA-15
        <ul>
            <li>Broadcast  : 137.62 Mhz</li>
            <li>Bandwidth  : 37.5   Khz</li>
            <li>Period     : 101.2  Mins</li>
            <li>Inclination: 98.7   Deg</li>
        </ul>
    </li>
</ul>
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    <figure>
        <img src="../img/NOAA-19.jpg" class="fig-img"></img>
        <figcaption>NOAA-19 before it was launched</figcaption>
    </figure>
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    <p>Here are some example images before we get into a how-to:</p>
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    <figure>
        <img src="../img/noaa-19-08072254-pris.jpg" class="fig-img"></img>
        <figcaption>NOAA-19, 08-07-20, 22:54 UTC</figcaption>
    </figure>
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    <figure>
        <img src="../img/noaa-19-08252244-pris.jpg" class="fig-img"></img>
        <figcaption>NOAA-19, 08-25-20, 22:44 UTC</figcaption>
    </figure>
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<p>You can pretty clearly see the mitten of Michigan in both (its upside down
in the image on the left). The orientation of the image is determined by the
direction that the satellite is traveling when it flys overhead.</p>

<p>Hopefully you find this cool enough that you want to try this out
yourself. Its alot of fun and feels great to see the progress over time.</p>

<p>To get started with this hobby you won't need much, just a
laptop/desktop/raspberry pi, an SDR, and a decent antenna (sometimes comes with
the SDR). I've provided some amazon links to the hardware I've actually used.</p>
<ul>
    <li class="link-list-item"><a href="https://www.amazon.com/RTL-SDR-Blog-RTL2832U-Software-Defined/dp/B011HVUEME">
            All in one kit</a></li>
    <li class="link-list-item"><a href="https://www.amazon.com/NooElec-Software-Defined-Antenna-Adapter/dp/B01K1CCHR0">
            HackRF (SDR)</a></li>
    <li class="link-list-item"><a href="https://www.amazon.com/RTL-SDR-Blog-Multipurpose-Dipole-Antenna/dp/B075445JDF">
            Dipole Kit</a></li>
</ul>
<p>With this I would watch some of the tutorials on youtube, or maybe I'll put
a tutorial up myself at some point. It's suprisingly easy to do and only takes
maybe 10 mins to setup each time.</p>

<p>A full repository of every attempt I've had can be found
<a href="https://git.clortox.com/tyler/satellite">here</a>.</p>
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