$25 Satellite Tracker Boasts “Usefulness Optional”

[Paul] is very up-front about the realities of his $25 Satellite Tracker, which aims a tape measure yagi antenna at a satellite of choice and keeps it tracking the satellite as it moves overhead. Does it work? Yes! Is it cheap? Of course! Is it useful? Well… did we mention it works and it’s cheap?

When [Paul] found himself wanting to see how cheaply he could make a satellite tracker he already had an RTL-SDR (which we have seen used for satellite communication before) and a yagi antenna made out of a tape measure, but wanted some way to automatically point the antenna at a satellite as it moved across the sky. He also wanted to see just how economically it could be done. Turns out that with some parts from China and code from SatNOGS (open-source satellite tracking network project and winner of the 2014 Hackaday Prize) you have most of what you need! A few modifications were still needed, and [Paul] describes them all in detail.

Satellite Tracker In Parking Lot ThumbnailSo is a $25 Satellite Tracker useful? As [Paul] says, “Probably not.” He explains, “Most people want satellite trackers so that they can put them outside and then control the antenna from inside, which someone probably can’t do with mine unless they live in a really nice place or build a radome. […] Driving somewhere, setting it up correctly (which involves reprogramming the Arduino for every satellite), and then sitting around is pretty much the opposite of useful.”

It might not be the most practical but it works, it’s cool, he learned a lot, and he wrote up the entire process for others to learn from or duplicate. If that’s not useful, we don’t know what is.

Satellite tracking is the focus of some interesting projects. We’ve even seen a project that points out satellite positions by shining a laser into the sky.

54 thoughts on “$25 Satellite Tracker Boasts “Usefulness Optional”

      1. you really are victim of the western propaganda. It is the US that keeps pushing and prodding the russians and restarting cold war. You probably think it is outrageous that the russians react by intercepting US spy planes coming straight to or above the russian border and airspace ( with transponders disabled ), and that those russians should not react when the US and NATO mass thousands of troops on the russian borders, and also when the US reneges on Reagan’s promise that NATO would not expand one inch to the east.
        the hypocrisy is mind boggling.

        1. Yeah and the US shoot down civilian planes full of kids, parents, siblings and the like! Oh no sorry, that was Russia. But damn that western propaganda, at least Russia doesn’t use propaganda…

          1. If you consider that cluster-f surrounding MH370 as ‘proof’ Russia ‘shot down; anything, you didn’t pay enough attention!

            Clearly if it was provable it was russia, that would have been bigger news – but that claim unraveled instantly when trotted out.

            Be more discerning, or dont comment on these events.

          2. I see another informed you of the US Navy bringing down that Iranian civilian airliner. We have reached a point where Czarist Russia, the USSR, former USSR states and the USA are guilty of so many similar atrocities it has to be ignorant for any them to point fingers at each other.

          1. It’s all posing, muscle-flexing. Putin’s ego vs the world’s most ludicrously over-developed military, and the arms manufacturers who need constant war to maintain their enormous income. Bunch of buttholes causing trouble for ordinary people, and it’s never those who make the decisions who die. Russia and the USA are both run by a bunch of horrible people. Can you imagine having a fun night out with any of them?

            There’s something wrong with politics when nice, normal people don’t get a look-in. There’s something wrong with people for voting for these nutcases. Still, Bernie and Jeremy Corbyn seem like the result of a reaction against this. We’ll find out for sure if they get into power. Maybe we’ll be fooled again. It’s nice for the moment to have some faith in the future for a change.

        2. Propaganda indeed! I have video from a small US ship in the 1980’s being buzzed for two days by everything in the Russian fleet from Hind’s to Floggers – first time a Flogger was seen up close and on tape. And so close you could hit them with a rock. The Hind went round and round and round…. They did not like their fleet exercise being observed :-) There was a nice little helicopter and I have some amazing video from the chopper looking into the cockpit of a pissed off Hind pilot from above, through his rotor. Then parking in the landing pattern of a carrier to see the fuel endurance of the Russian Harrier copy. Not very long. The Harriuskies fired some practice missiles off the bow to say they were tired of playing. None of it made the press. Someday I can post it. Quality is messed up by all the RADAR being so close, except the cockpit video. (For a few years there was a U.S. Navy specialty called Ocean Systems Technician which was basically the US version of a Russian Trawler observation vessel with PDP-VAX sized computers and sub tracking and radio systems. Later, in the 80’s it became a properly marked small ship with lots of radio gear and a small helicopter and a couple spooks added to the Navy crew.)

          Too bad we have forced Putin to give weapons to Iran and invade “friendly” countries with Spetsnaz in unmarked uniforms and deny it is happening while we watch. (Don’t mess with those guys.)

          Gotta say that the return of close intercepts over international waters and all the probing around Scandinavia and Alaska by Bear Bombers brings back memories and breaks up the boredom. Why the Obama admin and the press are so excited about it is beyond me.

          Evil US. Team America, World Police!

          1. Fly overs are provocative, but not exactly evil incarnate.

            Trying to blame one side over the other on the cold war 1, and the neo-cold war we now are having foisted on us is the height of folly.

            Taking either scurrilous side is like choosing a serial killer to defend.

          2. It is pretty easy to name the bad guy in the Cold War. Some dictator who purged people who disagreed with him and killed around 50 million of his own people, gobbled up half of Europe and built walls to keep people in. Add stealing hydrogen bomb plans from the US and building up a huge ICBM system and shorter range to reach all of European countries. Stir in a heaping cup of tanks constantly practicing invasions and you get plenty of tension. Totally avoidable by someone more reasonable.

          3. The soviets never stole “hydrogen bomb plans.” They did steal atomic bomb plans, and used them to build their first copy of Fat Man, but Sakharov was already improving the design and the exact copy was ordered from above out of fear anything else might embarrassingly fail. The real secret of the atomic bomb is that it is possible to build them at all, and we let that one out of the bag at Trinity.

            They improved to 500 kilotons using fusion boosting with no help from us, since they weren’t fanatically intent like Ed Teller on unlimited yield. And after we demonstrated 10 megatons with Mike, it only took about a year for them to figure out how we did it; once you know it’s possible, there aren’t a lot of ways to do even maybe do it and you know for sure one of them works.

        1. Yeah, because we caused the expansion of Russia into Crimea. Guess we’re to blame for China militarizing and occupying the islands in the South China Sea? Is our relationship with foreign countries perfect? No, but don’t blame the current political atmosphere on a single nation.

          1. You could always say “he started it”. They’re all doing it to maintain face in front of each other, and their people, and grab a little on the side for themselves. Meanwhile society is collapsing and poor people starve to death and die of illness in rich countries. I could go on, but George Orwell summarised it pretty well in 1948.

          2. One nation claims to lead the world, so maybe it IS appropriate to blame things on that one nation.

            The way international incidents surrounding contested territory works is quite alarming to a powerless citizenry, but we cannot ignore the facts: military and globalist forces do things for their own reasons, then make up more palatable reasons to tell us citizens.

          3. Actually, yes the expansion into Crimea is the direct result of our meddling with the old Ukranian goverment and replacing it with our own puppets. Now Ukraine is forced to take loans it can never pay back, but the current leaders don’t give a crap. They are too busy selling the Ukraine piece by piece. And when there is nothing left to sell, they will just go live in the other countries.

    1. I do this all the time, except by hand. There are TONS of ham radio satellites and some you can work with your $35 china radio.

      Being able to automate it? even better, place that antenna with a nice helical so you dont have to add a third servo to change polarity angle

    2. I was around from almost Day One of the Cold War (born in 1948). The hysteria that some have been telling you about was bosh. As president, Eisenhower was so obviously competent, we didn’t worry. We knew a guy who’d successfully commanded one of the largest multi-national forces in history could keep the Soviets well-behaved.

      What trouble there was came only with JFK, with his ill-founded hysteria about a “missile gap.” Ike had our intelligence source show candidate JFK that there was no missile gap. The USSR had only ten ICBMs and at any particular time only two were operational, given that they were liquid fueled and a nusiance to deal with. That mattered not. JFK wanted to be president and if he had to lie to do so, he would. The result was that the White House passed into the hands of a rich dilettante who had boched the command of a mere PT boat.

      You can find details about that bogus missile gap here:


      Soviet premier Khruschev soon realized that JFK was in over his head. The USSR put up a wall in Berlin and introduced nuclear missiles into Cuba. JFK put up with the first and would have put up with the second but for the dreadful political implications he’d face in 1964 if those missiles remained. The result of a weak JFK was the closest we ever came to WWIII, the Cuban missile crisis. That’s also the closest we came to a Cold War hysteria, with a brief fad for fallout shelters, a fad so shallow, I’ve only encountered one such home shelter in my entire life.

      So no, it someone had set up that little antenna in a parking lot during the Cold War, there’s have been no hysteria. People would have just gathered around and asked what it was.

      I might add that, in my experience, people who project non-existent hysterias on other people and other times are precisely the ones who display little emotional stability themselves. They assume others are like them. They aren’t.

  1. Could this code be used to track a UAV based on GPS coordinates perhaps? You can get pretty nice range and bandwidth with directional Wi-Fi antennas. Cheap HD FPV.

    1. its called an antenna tracker, people have made them and wise old farts seem to have a pretty “get off my lawn” type attitude about them. Apparently in the end its just a big complex machine to fail versus a glorified stick in the ground (normal antenna that just works) . Some GCS actually have it all set up ready to go and there are examples of opentrackers and stuff you can find. Its all basically the same 2 axis cnc with varied control inputs (orbitron for satellites and things , or your GCS if it has the setup ready in it. )

  2. Mine works fine, I found the weak link to be homing it properly and accurately enough to get a good signal. That and the orbitron software i used on the pc side did not seem to keep accurate time. I had +\- 15 mins on each machine my desktop, and my laptop i was setting up for the ISS SSTV event that just recently ended. I ended with a decent reception of a picture but missed the majority of the event. Next go around I plan to use one of the paid for pc side apps (50$) and see if i can make it easier to home. It is actually useful , even if you are hand aiming it to give you a good idea where to point it.

  3. I am typing this without having read the expanded post of info. Couldn’t one set up a master/slave relationship where the computer knows where it is and what it wants to look at and then tell the arduino where to point? Basically, use the right tool for the right job.

    1. So you are going to skip reading the actual article, write up a post with questions, and presumably check back to see the answer to your question… but not take the ~1 minute to read the article? I truly hope nobody posts anything useful for you here.

      1. Slashdot has featured quite a few HaD articles in the past couple months. Now, between the “didn’t even read the summary” and the unhelpful political comments, it seems we’ve onboarded a few slashdotters. That isn’t necessarily a bad thing, but they need to unlearn some bad posting habits.

      2. Id argue being a dick to people based on their presumed laziness is the exact sort of thing that takes people casually interested and turns them away or keeps them from being curious enough to learn and become what you consider worthy of asking a question.
        Id argue its a dam good question for a casual, to post before they read so it shows theyre thinking.

    1. I ended up using 5 to one planetary steppers for a bit of torque to combat windage . It still needs counterweighting . Check this post on fb or g+ i forget which , in the comments i put a picture.

  4. So I wonder if you could use a Pi for the SDR as well as controlling the antenna?
    Hook it up with a battery pack or an extension cord in your backyard and use wifi for comm

    1. Can you use Wifi when you’re tracking satellites? A transmitter right next to your sat receiver, satellite signals are pretty weak. Of course the solution is just to use a wire.

      1. He’s receiving at ~ 130Mhz. Wifi is at 2.4 or 5GHz.

        It’s true, out of band signals can overload a receiver if they are strong enough. I would not suggest sticking the WiFi antenna right in the path of the yagi. Also, if he were to mount wifi equipment directly to the tripod (as I suggest in another comment) I would suggest configuring it to only use as much power as needed, not just automatically go full blast.

        Given reasonable choices like that I wouldn’t expect any problems at all!

      2. You could use an ethernet cable but you would should really think about some lightning protection if you are going to run it into your home. The Yagi he was using looked to me to be VHF and not even close to 2.4Ghz so odds are good that with a little bit of effort like some shielding like putting the wifi transmitter in a metal box with one open side and grounding the box you would not have an issue as long as the open side was pointed at your house and not the yagi.

    1. Not all yagis have isolated elements. Some are designed to be at DC ground, which is actually a good idea in many cases.
      In fact, many antennas have elements that aren’t separated in any way, and can have a direct connection to Earth ground and still work perfectly. The J-Pole is a good example, as is the Arrow Yagi that I used to have (Arrow being the company that made it). Ground at DC isn’t necessarily ground at frequency.

    2. Antistatic materials are conductive, but have a pretty high resistance. Between 10^5 and 10^12 ohms according to a quick Google. Just discovered a bit ago what “ohms per square” means. Still don’t quite understand it. Probably applies to those.

      Still, it works!

  5. I don’t think your project is useless! Sure, it’s not something that you could just permanently mount outside but it doesn’t look like it would be that hard to just go set it in your back yard when you want to use it. I think it looks like a fun toy to bring to a field day event… provided good weather anyway. You could always use some thin bamboo skewers or something like that to stiffen up the elements if need be.

    ” (which involves reprogramming the Arduino for every satellite)” From that I thought you were actually hard coding information into constants and had to rebuild your sketch. From what I gathered by skimming your page it looks like you are just sending direction info via serial. That isn’t so bad! If you want to make it a little easier you could always hook up a bluetooth serial adapter like an HC05 or something. That would make it more convenient to repoint. Or…

    How about mounting a RasPi to the tripod? My reasoning for that is it would not just handle sending the positioning data. It would also be the receiver! That way you could make the antena wire really short for minimum loss. Just make sure to put the electronics in some sort of metal case for RF shielding. You could configure the RasPi for an AdHoc connection. Then you can easily link up to it wirelessly using your cellphone or a tablet to control it.

    1. For bonus points skip the RasPi and just use an old cellphone. I know there is an Android app for RTL-SDR. I have used it myself! Is there an app which will send the positioning data to the antenna via some sort of serial connection? I don’t know.

    2. It’s somewhat useless now, but still looks like fun. Certainly with a bit more development he could have something very useful and cool. Being able to do it on a small budget wouldn’t have been possible a few years ago. If he writes it all up properly, it might be a resource for lots of others.

      1. The choke point is accurate timing , I only had one pass of the ISS to test but being off by 30 seconds or a minute is actually pretty substantial. The timing has to be perfect for a nice strong signal thru out a pass. In my experience its easier to grab the yagi and point it. People next door were more amused too.

  6. Use case.

    Often travel to the BWCA, I used to carry a “spot” transmitter, but that was pricy so I got a ham license figured I’d use APRS and just tell some one back in civilization to check on my location every day I was out, and I could send messages if need be…

    Problem no APRS coverage out in the BWCA, satellites could fill this coverage gap, and a old cell phone could provide a message(I’m ok, or Send help, or stuck in a storm), GPS coordinates, and even track the satellite, electronic compass on board could make the tracking work even if the antenna was mounted on the back of a moving canoe while crossing a large lake…
    Cheap lightweight Satellite tracker fit’s the bill perfectly for automating that contact.

    The other problem is that I don’t believe there are any reliable APRS satellites left… and to few unreliable ones to count on them for any kind of coverage… Maybe Am-Sat or someone will be able to put of a small swarm of Cubesats to fill that purpose on a cheap end of life spacex rocket…

  7. I think this project is super cool. Having started collecting parts to do some H-Line backyard radio astronomy, I have grown to love seeing these sorts of things!

  8. Here’s mine.

    I never finished the documentation, but I put the servo control code on an Arduino Nano and stuffed it inside the tube. Everything is powered by four AA NiMH cells.

    Here’s the Arduino code:

    Then I stuck a Bluetooth receiver on it. I run the open-source ‘predict’ program on my laptop to calculate satellite positions, and it sends azimuth and elevation values to the Arduino via the Bluetooth serial link.

    1. sorta the way I did it, I won an Arduino Ethernet shield and was looking for some thing to do with it.

      have you ever jumped out of your skin when Predict says “out of nowhere”,

      “This is Predict, satellite is at degrees and approaching”??

  9. this looks pretty cool!

    under Linux there is a package called “Predict”, in server mode it will output azimuth and altitude data on port 1280(?)

    So far I’ve only used it to track the moon for a timelapse shoot

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