Like many of us, [Gabe] has things he just can’t stop buying. In his case, it is portable satellite dishes. You’ve seen these. They look like a dome or maybe a hard hat on some kind of motorized base. What’s in them? What can you do with them? Watch the video below and find out.
As [Gabe] points out, you can often find these on the surplus market for very little money. You can sometimes find them on the side of the road for free, too. Although we’ve never been that lucky.
The video shows three generations of Winegard antennas. It shows what’s inside and how to command them. Of course, the obvious use for these is as an antenna. But we also were thinking they’d make a fair motion base for something, too.
Some of the antennas lack any limit switches. On startup, the system spins until it grinds the plastic gears to find its travel limits. We expect that’s not good for the gears, but it does work. [Gabe] mentions it might be a bit of planned obsolescence, but we imagine it is more of a cost-saving measure.
These days, affordable software defined radios (SDRs) have made huge swaths of the spectrum available to hobbyists. Whether you’re looking to sniff the data from that 433 MHz thermometer you’ve got in the backyard or pick up transmissions from satellites, the same little USB-connected box can make it happen.
But even the best SDR is constrained by the antenna it’s connected to, and that’s where it can still get a little tricky for new players. Luckily, there’s a new option for those who want to pick up signals from space without breaking the bank: the Discovery Dish by KrakenRF. After reaching 105% of its funding goal on December 20th, the handy little 65-cm aluminum reflector looks like it’s on track to ship out this summer.
The Discovery Dish was designed from the ground up to enable hobbyists to receive real-time weather data from satellites transmitting in the L band (GOES, NOAA, Meteor, etc.) and experiment with hydrogen line radio astronomy. Neither of which are anything new, of course. But having a pre-built dish and feed takes a lot of the hassle out of picking up these distant signals.
Although the current prototype has a one-piece reflector, the final Discovery Dish will break down into three “petals” to make storage and transport easier. If you don’t want to take it all the way apart, you can simply remove the feed to make it a bit more compact. Speaking of which, KrakenRF is also offering three different feeds depending on what signals you’re after: L band, Inmarsat, or hydrogen line.
The amateur radio community has exploded with activity lately especially in the software-defined radio (SDR) area since it was found that a small inexpensive TV tuner could be wrangled to do what only expensive equipment was able to do before. One common build with these cards is monitoring air traffic, which send data about their flights out in packets over the radio and can easily be received and decoded now. It turns out another type of vehicle, SpaceX’s Falcon 9 spacecraft, reports data via radio as well and with some slightly upgraded hardware it’s possible to “listen in” to these flights in a similar way.
Reddit users [derekcz] and [Xerbot] used a HackRF module to listen in to the Falcon 9’s data transmissions during its latest launch. While the HackRF is a much more expensive piece of equipment compared to the RTL-SDR dongles used to listen in on aircraft, it is much more capable as well, with a range from 1 MHz to 6 GHz. Using this SDR peripheral as well as a 1.2 m repurposed satellite dish, the duo were able to intercept the radio transmissions from the in-flight rocket. From there, they were recorded with GNU Radio, converted into binary data, and then translated into text.
It seems as though the data feed included a number of different elements including time, location information, and other real-time data about the rocket’s flight. It’s a great build that demonstrates the wide appeal of software-defined radio, and if you want to get started it’s pretty easy to grab a much cheaper dongle and use it for all kinds of applications like this. Go check out [Tom Nardi]’s piece on the last seven years of RTL-SDR to get caught up to speed.
When [Kenneth Keiter] took apart his Starlink dish back in November, he did his best to explain the high-level functionality of the incredibly complex device in a video posted to his YouTube channel. It was a fascinating look at the equipment, but by his own admission, he wasn’t the right person to try and explain the nuances of how the phased array actually functioned. But he knew who could do the technology justice, which is why he shipped the dismembered dish over to [Shahriar Shahramian] of The Signal Path.
Don’t be surprised if you can’t quite wrap your head around his detailed analysis after your first viewing. You’ll probably have a few lingering questions after the second re-watch as well. But that’s OK, as [Shahriar] still has a few of his own. Even after cutting out a section of the dish and putting it under an X-ray, it’s still not completely clear how the SpaceX engineers managed to cram everything into such a tidy package. Though there seems to be no question that the $500 price for the early-access hardware is an absolute steal, all things considered.
The layered antenna works on multiple frequencies.
Most of the video is spent examining the stacked honeycomb construction of the phased antenna array, which as expected, holds a number of RF secrets if you know what to look for. Put simply, there’s no such thing as an insignificant detail to the trained eye. From the carefully sized injection molded spacer sheet that keeps the upper array a specific distance from the RF4-like radome, to the almost microscopic holes that have been bored through each floating patch to maintain equalized air pressure through the stack up, [Shahriar] picks up on fascinating details which might otherwise seem like arbitrary design decisions.
But a visual inspection will only get you so far. Eventually [Shahriar] has to cut out a slice of the PCB so he can fit it into the X-ray machine, but don’t feel too bad, the dish was long dead before he got his hands on it. While he hasn’t yet completed his full analysis, an initial examination indicates that each large IC and the eight chips surrounding it make up a 16 channel beam forming module. Each channel is further split into two RX and TX pairs, which provides the necessary right and left hand polarization. That said, he admits there’s some room for interpretation and that further work would be necessary before any hard conclusions could be made.
Between this RF analysis and the initial overview provided by [Kenneth], we’ve already learned a lot more about this device than many might have expected considering how rare and expensive the hardware is. While we admit it’s not immediately clear what kind of hijinks hardware hackers could get into once this device is fully understood, we’re certainly eager to find out.
While SpaceX’s constellation of Starlink satellites is nowhere near its projected final size, the company has enough of the birds zipping around in low Earth orbit to start a limited testing period they call the Better Than Nothing Beta. If you’re lucky enough to get selected, you have to cough up $500 for the hardware and another $100 a month for the service. Despite the fairly high bar for getting your hands on one, [Kenneth Keiter] decided to sacrifice his Starlink dish to the teardown Gods.
We say sacrifice because [Kenneth] had to literally destroy the dish to get a look inside. It doesn’t appear that you can realistically get into the exceptionally thin antenna array without pulling it all apart, thanks in part to preposterous amount of adhesive that holds the structural back plate onto the PCB. The sky-facing side of the phased array, the key element that allows the antenna to track the rapidly moving Starlink satellites as they pass overhead, is also laminated to a stack-up comprised of plastic hexagonal mesh layers, passive antenna elements, and the outer fiberglass skin. In short, there are definitely no user-serviceable parts inside.
The dish hides many secrets under its skin.
Beyond attempting to analyze the RF magic that’s happening inside the antenna, [Kenneth] also takes viewers through a tour of some of the more recognizable components of the PCB; picking out things like the Power over Ethernet magnetics, a GPS receiver, some flash storage, and the H-Bridge drivers used to control the pan and tilt motors in the base of the dish.
It also appears that the antenna is a self-contained computer of sorts, complete with ARM processor and RAM to run the software that aims the phased array. Speaking of which, it should come as no surprise to find that not only are the ICs that drive the dizzying array of antenna elements the most numerous components on the PCB, but that they appear to be some kind of custom silicon designed specifically for SpaceX.
Students from the Indian Institute of Science Education and Research combined a commercial satellite dish, a satellite finder and an Arduino, and produced a workable radio telescope. The satellite dish provides the LNB (low noise block) and the associated set-top box is used only for power. Their LNB employs an aluminum foil shield to block extraneous signals.
In addition to the hardware, the team built Python software to analyze the data and show several practical applications. They used known geostationary satellites to calibrate the signal from the finder (digitized by the Arduino) to determine power per unit voltage. They also calculated the beam width (about 3.4 degrees) and used the sun for other calibration steps.
Satellite dishes are a common site these days, although admittedly most of them are Ku- and Ka-band dishes. The older C-band dishes are still around, though, just less frequently in people’s yards. [Greenish Apple] decide to cut the cable and start watching free TV so he built a C-band dish. The trick is, he made the dish out of wood.
The design is the offset type, not a prime focus dish–that is, the electronics are not in the center of the dish but on the side. Wood isn’t particularly good at reflecting RF, of course, so over the wooden skeleton, he used flashing.
