Pictures From 22,000 Miles Away Sent To Your Backyard
July 12, 2019 7:25 AM   Subscribe

A step-by-step tutorial to receiving GOES-16 weather satellite images for under $200.

Using an RTL-SDR USB stick, a long-range WiFi antenna, a Raspberry Pi, and the open source Goestools you can receive pictures of the earth, weather forecasts, and other data - all sent from some 22,000 miles away in geostationary orbit. (GOES-16 previously, RTL-SDR previously) [via]
posted by Nonsteroidal Anti-Inflammatory Drug (12 comments total) 44 users marked this as a favorite
Based on the linked guide I built this myself over the past month. It's pretty amazing to view the goesrecv tool's error rate in real time as you slowly adjust the aim of the WiFi antenna rated for 8 miles, and all of a sudden you start getting a signal from SPACE! A few helpful tips:
  • Apparently flipping the end reflector around on the antenna, so it's more of a (---< thing instead of (--->, helps with the signal, particularly if, like me, you don't have access to a 3D printer to push the reflect out a centimeter or two as described.
  • The guide links to AGSatTrack for aiming, but it's a little hard to use. Dish Pointer gives you directional information based on true and magnetic north, so you can use a compass, and shows the direction overlayed on a map so you can have some landmarks.
  • This compass that I found on Amazon has a clinometer which was helpful for initial aiming.
  • The guide glosses over the antenna assembly a bit. I strongly recommend using a tripod (I found one on Craigslist), as you'll need some sort of holder anyway. I initially tried to be clever and use an existing mount on the side of my house but then I could adjust the aiming while viewing real-time data. It's a lot easier to just have the antenna right in front of you as you work on everything.
posted by Nonsteroidal Anti-Inflammatory Drug at 7:39 AM on July 12, 2019 [14 favorites]

This is so awesome! Could you share some example images you’ve received?
posted by suedehead at 7:59 AM on July 12, 2019 [1 favorite]

75.2W GOES 16 (about two thirds of the way down) on the Dishpointer Satellite pull down Menu
posted by nanolightbender at 8:13 AM on July 12, 2019 [1 favorite]

I don't have my images posted anywhere publicly available right now and I don't have my hard drive with me right now that I saved everything to. If I have time today or this weekend I'll toss some up on imgur.

In the meantime pages 57 through 62 of this large PDF show examples: you get pictures in various spectrums, weather charts, and text data.

I should note that most (all?) of this data is actually a retransmission of processing done here on the ground based on the original satellite imagery - that is, the satellite takes pictures and sends them to a ground station, which processes the data, and then sends it back along with charts and things, which the satellite then sends out on a different band than the original signal. You need a very large dish to pick up the raw data.

Bonus Link: The satellite doesn't take full color photographs (Wikipedia says "Lacking an explicit band for green light, true-color imagery for ABI is created using the combination of the ABI's red and blue visible bands along with a synthesized green band; the simulated green band is created by applying algorithms based on MODIS and AHI onto existing ABI spectral bands"), so that means you can play with the coloring algorithms.
posted by Nonsteroidal Anti-Inflammatory Drug at 8:27 AM on July 12, 2019 [1 favorite]

I know this is missing the point, since it's just an internet thing, but people with Macs might be interested in the Downlink app. Every 20 minutes it grabs the latest image from one of a selection of satellites, including GOES, and updates your desktop.

My SDR Pi is currently doing ADS-B aircraft tracking for FlightAware, but I quite fancy trying out satellite comms next. I had thought the aerial was more complicated than what you've posted about, so that's encouraging!
posted by rhamphorhynchus at 8:30 AM on July 12, 2019 [3 favorites]

I had thought the aerial was more complicated than what you've posted about, so that's encouraging!

The secret sauce here is that the GOES satellites don't move (more or less) so you just line things up and call it a day.

I originally picked up the SDR stick a few years ago to try and catch NOAA images, but since those orbit the earth in the traditional sense, you have to have an antenna to handle the rotating signal, and you can only get images while the equipment is overhead. I never ended up getting around to doing that.

The orbit also leads to trickier troubleshooting, and the imagery seems to be noisier since there's a lot more chances for things to go wrong with moving signals. On the other hand once I got aimed up with GOES-16 my first image was pixel perfect with no static or missing lines.
posted by Nonsteroidal Anti-Inflammatory Drug at 8:34 AM on July 12, 2019 [1 favorite]

Living in the future has it's moments.
posted by zenon at 8:58 AM on July 12, 2019 [1 favorite]

OMFG!! I have EVERYTHING I need to do this sitting on my dining room table right now! BUT!
I'm also packing up the camper can for a weekend jaunt. Boo.
Sunday night is sure gonna be fun. Thanks!
posted by Floydd at 10:25 AM on July 12, 2019 [4 favorites]

Cool stuff. I have been wanting to capturing the NOAA images using the technique in the comment from NSAID, but haven't gotten around to it. I think my tape measure antenna for the 2m amateur radio band would probably work well enough.
posted by exogenous at 10:50 AM on July 12, 2019 [1 favorite]

Here's a selection of images and text I received over the past few days, containing:
  • full color, "full disk" images - not entirely true color as explained in my earlier comment
  • zoomed images of the gulf coast, which are sent as shown in addition to the full disk
  • zoomed images of the midwest, also sent as shown
  • weather charts
  • plain text weather reports, as well as English and Spanish summary
  • plain text listing of radio channel assignments
  • the band 13 relay from GOES 17, showing the Pacific
In addition to this I received the other various channels of imagery, such as the numerous infra-red and near infra-red to show cloud and vegetation levels, for the continental US full disk and zoomed-in regions. The GOES 17 relay only seems to be for band 13.

The map overlay is done by the image processing software as far as I can tell. The images contain navigational data which means you can match up GeoJSON.
posted by Nonsteroidal Anti-Inflammatory Drug at 7:46 PM on July 15, 2019

Wow, those look great! In comparison, my SSTV images from the space station are full of noise - local urban sources I guess.
posted by exogenous at 10:28 AM on July 16, 2019

If I ever get around to trying this (probably not before this thread closes unfortunately), I am likely to try and homebrew an antenna, maybe based around one of these adjusted for the higher frequency.
posted by exogenous at 1:22 PM on July 16, 2019

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