Hacking Portable Satellite Dish For More Space Experiments
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Published 2024-01-10
I used a string of serial cable adapters to get a console on the Carryout dish brain, then I could control it with a Python program. The dish moves through a specified angle and elevation range and takes a signal reading at each position. These can be combined into an image of the sky where each pixel is a radio signal. Then you can "see" things like satellites and radiation patterns.
The prior version only used the onboard Ku-band receiver on the dish. This version replaces the LNB with an RTL-SDR (Software-defined radio) and L-band antenna. Other radio bands could be used, but microwave probably works the best.
I'd like to turn this into a Wifi imager eventually. I did some brief experiments with Wifi (S-band) using a downconverter, but I didn't get very far with that.
My best images so far include an Inmarsat geostationary satellite, navigation satellites, and Iridium comm satellites. All of these can be "imaged" with the dish, although they appear a little different due to the relative speed of the dish and the satellite! For example, Iridium showed up as one long streak (kind of like a time exposure picture). GPS / Gallileo / Beidou showed up as many small points on an orbital track. Inmarsat showed up as fixed a point source in the sky.
I have a writeup on my website with more information about this project here: saveitforparts.wordpress.com/2023/12/29/another-po…
My code is available on Github here: github.com/saveitforparts/Carryout-Radio-Telescope…
You will need an RS-232 to RS-485 adapter. I used this one:
www.amazon.com/dp/B01CXY9S6M?linkCode=ssc&tag=onam…
Used satellite antennas like this often show up on Craigslist, Facebook Marketplace, and other used sites. They're worth about $25-$50USD. Sometimes people ask more, but I just wait until they go unsold for a month and the price drops, or wait for someone else to list one cheaper.
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All Comments (21)
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"Just one more satelite dish bros... I promise its the last one. Just one more. One more satelite dish.. just one more. I only need one more.."
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I don't have the slightest clue what you are doing, but i really enjoy watching you do whatever it is your doing.
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We love recreational python coding
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HAL usually refers to the Hardware Abstraction Layer... but hey... the HAL9000 has the utmost enthusiasm for the mission, so that works too!
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He’s got a lot more patience than I do. He keeps saying this annoying problem, that annoying problem, yet shows not a hint of annoyance. I would have already been throwing things around, getting mad, cussing. Kudos to you sir!
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You could use a rotary encoder to show the exact position of the dish and use that as error correction.
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The panic of plugging in a serial port into a moving assembly is... fun :) Another phenomenal video!
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Easily one of the coolest channels I've ever come across. I love the scripting too.
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I like the filming of the screen, it fits the vibe of the channel better lol
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I don't understand half of what he's doing but it's the professionaly winging it that has me hooked.
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Fun fact about those Prolific serial adapters, it's not that they're necessarily flaky, it's that the market is riddled with counterfeits. It's entirely possible you have one and the genuine article might work better. If you look up "computers are bad - prolific counterfeits" there's a really interesting read about them. It's actually pretty crazy the lengths that Prolific has gone to in order to defeat counterfeiters, so much so that they screw over legitimate customers.
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You aren't grinding any gears, the grinding noise you are hearing is just the stepper motors losing steps. This is actually a pretty common way for motion control systems w/o feedback sensors to find 'home'. The stepper motors will skip steps at torque levels far below the point where it would cause damage to belts or gears, making it a cost effective (although scary sounding) way to home a system. Some/older 3D (and 2D) printers do this, as do CD/DVD drive readers, some flatbed scanners, etc. If you are losing steps/position while the unit is operating, that is likely a result of moving the system too fast. Stepper motors have a torque curve, and at high speeds they have a high chance of skipping.
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Your cheesy telephone cable may be the culprit. Higher bit-rates require better cables -- even for these "glacial by todays network standards" speeds. Back when I was a young pup, we ran RS-232 everywhere -- because you had terminals and a central computer. Getting things to work above 9600BPS required better cabling--particularly for longer cabling.
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When it's starting and grinding the gears, I think it's doing that because the current limit feed back is set to high. If their is any adjustability for it, adjusting it down may stop the over torquing issue.
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Was the serial port on the Linux server possibly just disabled in the BIOS? I love the huge range of tech and scripting you cover on this channel BTW!
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Amazing work for a backyard enthusiast! Love watching your projects develop. Love from NZ
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Well now that I know it can be done, I simply must make a radio telescope!
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Hands down one of my favourite channels.
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I think it's as simple as the whole waveguide is just the wrong size for L-band. Fascinating experiment, mate. Thanks for the great content.
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I really enjoy your videos! Your determination is inspiring!
