#phasedarray

2024-09-11

In 1905, Karl Ferdinand Braun showed how an array of antennas can adjust their phases to aim a radio broadcast, also used today for advanced radar systems. #Poetry #Science #History #Electromagnetism #PhasedArray #Braun (sharpgiving.com/thebookofscien)

A hut (with a window and a door) in the middle between three masts. Wires run from the hut to to run from the base to the tops of the poles.
2024-09-02

@freifunkradio was ich zu dem Thema Antennen auch nochmal interessant fände: #PhasedArray Antennen. Hielt das bisher immer für utopisch / zu teuer für Freifunk. Bis ich jetzt gelesen hatte, dass die #60GHz Mikrotik Antennen auch sowas hätten. Wäre es theoretisch denkbar, in Open Hard- + Software sowas selber zu entwickeln/bauen?

2023-04-11

A _phased aray_ is a line (or grid) of antennas where we can tune the phase of each antenna, to use interference to change the direction where most of the signal energy goes!

In his beautiful video, Nils Berglund has staggered the frequencies of his 19 antennas to achieve a nice sweeping effect!

It's nice to see the same sweep twice, but don't you also wonder how it might look like if the video would run a little further? Nils has been developing his inspections of phase arrays in a dramatic fashion for a while now, and this is just the most recent in an on-going series of videos.

youtube.com/watch?v=zI3IwYxuht

#phasedArray #eyeCandy

en.wikipedia.org/wiki/Phased_a

dr 🛠️🛰️📡🎧:blobfoxcomputer:davidr@hachyderm.io
2023-01-13

@winstonsmith This sounds really fun and cool. I've wanted to mess with #phasedarray but like...from scratch. I.e. not as a way of doing #ham, but just to figure out how.

That said, I don't think this rules out a hardware issue. If anything "our receiver is really complicated, it must not have any problems" seems...not very convincing.

The "different receivers see the same thing" is a lot more compelling.

2023-01-12

New video! What benefits can you get out of having a radar system that has the ability to generate multiple beams of various different shapes?

In past Tech Talks, I've talked about the basics of radar and the basics of beamforming. Now, let's put them together and look at some of the ways that digital beamforming has improved radar systems.

youtu.be/Hb6BhqOgmAI

#phasedarray #beamforming #matlab #mathworks #radar

2022-05-15

Hackaday Links: May 15, 2022

It may be blurry and blotchy, but it's ours. The first images of the supermassive black hole at the center of the Milky Way galaxy were revealed this week, and they caused quite a stir. You may recall the first images of the supermassive black hole at the center of the M87 galaxy from a couple of years ago: spectacular images that captured exactly what all the theories said a black hole should look like, or more precisely, what the accretion disk and event horizon should look like, since black holes themselves aren't much to look at. That black hole, dubbed M87*, is over 55 million light-years away, but is so huge and so active that it was relatively easy to image. The black hole at the center of our own galaxy, Sagittarius A*, is comparatively tiny -- its event horizon would fit inside the orbit of Mercury -- a much closer at only 26,000 light-years or so. But, our black hole is much less active and obscured by dust, so imaging it was far more difficult. It's a stunning technical achievement, and the images are certainly worth checking out.

Another one from the "Why didn't I think of that?" files -- contactless haptic feedback using the mouth is now a thing. This comes from the Future Interfaces Group at Carnegie-Mellon and is intended to provide an alternative to what ends up being about the only practical haptic device for VR and AR applications -- vibrations from off-balance motors. Instead, this uses an array of ultrasonic transducers positioned on a VR visor and directed at the user's mouth. By properly driving the array, pressure waves can be directed at the lips, teeth, and tongue of the wearer, providing feedback for in-world events. The mock game demonstrated in the video below is a little creepy -- not sure how many people enjoyed the feeling of cobwebs brushing against the face or the splatter of spider guts in the mouth. Still, it's a pretty cool idea, and we'd like to see how far it can go.

Rest easy, Canadian space-farers: it is now illegal to commit murder in space. Or more precisely, the Canadian government has made anything that's illegal to do in Canada proper also illegal for Canadians to do in space. Given that only nine Canadians have made the trip upstairs since the 1980s, and because they're just so darn nice, there probably wasn't a huge risk of anything untoward happening in orbit, but that didn't stop Parliament from closing a potential loophole. The whole field of space law is actually kind of fascinating, and it'll be interesting to watch how it develops as we move further out into the solar system. But for now, everyone can feel a little safer heading into orbit with any Canadians.

And finally, wooden barrels may seem about as low-tech and anachronistic as buggy whips, but that's far from the case. Demand for wooden barrels, needed for the proper aging of wine and spirits, is still high, and watching the process of making barrels is downright fascinating. The amount of work that goes into coopered wooden barrels is amazing, and even with modern machine tools, it's still a very manual process. The idea that a watertight vessel can be made from wooden staves using absolutely no adhesives and no joints more complex than butting the staves up against each other is just mindblowing, and thinking about how it was done without machine tools like jointers and before the invention of hydraulic power is daunting. Enjoy!

#hackadaycolumns #hackadaylinks #slider #ar #astronomy #barrel #blackhole #canada #copperage #haptic #lips #m87 #milkyway #mouth #phasedarray #sgra #spacelaw #ultrasound #vr

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2022-02-24

Bend It Like (Sonar) Beacon With A Phased Array

Ultrasonic transducers are incredible, with them you can detect distances, as well as levitate and peer through objects. They can emit and receive ultrasonic soundwaves (typically above 18khz) and just like all waves, they can be steered via a phased array. [Bitluni] was trying to accurately measure distances but found the large field of view of the sensor was just too imprecise, so he made a phased array of transducers.

The inspiration came from a Hackaday Supercon talk from 2019 about phased arrays. [Bitluni] walks through an excellent explanation of how the array works with a bucket of water and his finger, as well as a separate simulation. By changing the phase offset of the different array members, the beam can effectively be steered as interference muffs the undesired waves. Using a set of solenoids, he created a test bench to validate his idea in a medium he could see; water. The solenoids fire a single pulse into the water creating a wave. You can see the wave move in the correct direction in the water, which validates the concept. A simple PCB sent off to a fab house with a stencil offers a surface to solder the transducers and drivers onto. An ESP32 drives the 8 PWM signals that go to the transmitters and reads in the single receiver via a small amplifier. Still not content to let the idea be unproven, he sets up the receiver on his CNC gantry and plots the signal strength at different points, yielding beautiful "heat maps."

It sweeps a 60-degree field in front of it at around 1-3 frames per second. As you might imagine, turning sound wave reflections into distance fields is a somewhat noisy affair. He projects the sonar display on top of what we can see in the camera and it is fun to see the blobs line up in the correct spot.

We noticed he built quite a few boards, perhaps in the future, he will scale it up like this 100 transducer array? Video after the break.

#digitalaudiohacks #microcontrollers #phasedarray #ultrasonic #ultrasonicarray

image
2022-01-22

Directional Antenna 3-Way

If you read old antenna books, you'll probably see the idea of phased vertical antennas. These use certain lengths of coax to control the phase of a signal going to three verticals in a triangular configuration. Depending on the phasing, you can cause the array of antennas to be directional in one of three directions. [DX Commander] designed a very modern version of this antenna and shows the theory behind it in a recent video that you can see below.

It seems another ham built the antenna and a control box for it which he's sent to [DX Commander] although he hasn't set it up yet to create an 80 meter directional antenna. We'll be interested in seeing how it works in practice.

Of course, the phasing delay line and the verticals will be tuned to a specific frequency, so you can't expect this to be a broadband system. It isn't small either since the verticals are placed a quarter wavelength apart and you need about the same amount of coax for the phasing cable (accounting for velocity factor).

The control box can select which vertical gets the delay and that controls the direction. You can also switch the delay out completely and wind up with an omnidirectional antenna.

This is probably not going to wind up being a cheap antenna, especially on 80 meters. While you don't often see phased arrays at HF, they are more common at higher frequencies.

#radiohacks #hamradio #phasedarray #radio #vertical

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2021-10-12

Ultrasonic Array Powers This Halloween Spirit Writer

The spooky season is upon us, and with it the race to come up with the geekiest way to scare the kids. Motion-activated jump-scare setups are always a crowd-pleaser, but kind of a cheap thrill in our opinion. So if you're looking for something different for your Halloween scare-floor, you might consider "spirit writing" with ultrasound.

The idea that [Dan Beaven] has here is a variation on the ultrasonic levitation projects we've seen so many of over the last couple of years. While watching bits of styrofoam suspended in midair by the standing waves generated by carefully phased arrays of ultrasonic transducers is cool, [Dan] looks set to take the concept to the next level. Very much still a prototype, the setup has a 256-transducer matrix suspended above a dark surface. Baking powder is sprinkled over the writing surface to stand in for dust, which is easily disturbed by the sound waves reflecting off the hard surface. The array can be controlled to make it look like an unseen hand is tracing out a design in the dust, and the effect is pretty convincing. We'd have chosen "REDRUM" rather than a pentagram, but different strokes.

[Dan] obviously has a long way to go before this is ready for the big night, but the proof-of-concept is sound. While we wait for the finished product, we'll just file this away as a technique that might have other applications. SMD components are pretty small and light, after all -- perhaps an ultrasonic pick-and-place? In which case, sonic tweezers might be just the thing.

#holidayhacks #halloween #phase #phasedarray #transducer #ultrasonic

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2021-07-04

Hackaday Links: July 4, 2021

With rescue and recovery efforts at the horrific condo collapse in Florida this week still underway, we noted with interest some of the technology being employed on the site. Chief among these was a contribution of the Israeli Defense Force (IDF), whose secretive Unit 9900 unveiled a 3D imaging system to help locate victims trapped in the rubble. The pictures look very much like the 3D "extrusions" that show up on Google Maps when you zoom into a satellite view and change the angle, but they were obviously built up from very recent aerial or satellite photos that show the damage to the building. The idea is to map where parts of the building -- and unfortunately, the building's occupants -- ended up in the rubble pile, allowing responders to concentrate their efforts on the areas most likely to hold victims. The technology, which was developed for precision targeting of military targets, has apparently already located several voids in the debris that weren't obvious to rescue teams. Here's hoping that the system pays off, and that we get to learn a little about how it works.

Radio enthusiasts, take note: your hobby may just run you afoul of authorities if you're not careful. That seems to be the case for one Stanislav Stetsenko, a resident of Crimea who was arrested on suspicion of treason this week. Video of the arrest was posted which shows the equipment Stetsenko allegedly used to track Russian military aircraft on behalf of Ukraine: several SDR dongles, a very dusty laptop running Airspy SDR#, an ICOM IC-R6 portable communications receiver, and various maps and charts. In short, it pretty much looks like what I can see on my own desk right now. We know little of the politics around this, but it does give one pause to consider how non-technical people view those with technical hobbies.

If you could choose a superpower to suddenly have, it really would take some careful consideration. Sure, it would be handy to shoot spider webs or burst into flames, but the whole idea of some kind of goo shooting out of your wrists seems gross, and what a nuisance to have to keep buying new clothes after every burn. Maybe just teaching yourself a new sense, like echolocation, would be a better place to start. And as it turns out, it's not only possible for humans to echolocate, but it's actually not that hard to learn. Researchers used a group of blind and sighted people for the test, ranging in age from 21 to 79 years, and put them through a 10-week training program to learn click-based echolocation. After getting the basics of making the clicks and listening for the returns in an anechoic chamber, participants ran through a series of tasks, like size and orientation discrimination of objects, and virtual navigation. The newly minted echolocators were also allowed out into the real world to test their skills. Three months after the study, the blind participants had mostly retained their new skill, and most of them were still using it and reported that it had improved their quality of life.

As with everything else he's involved with, Elon Musk has drawn a lot of criticism for his Starlink satellite-based internet service. The growing constellation of satellites bothers astronomers, terrestrial ISPs are worried the service will kill their business model, and the beta version of the Starlink dish has been shown to be flakey in the summer heat. But it's on equipment cost where Musk has taken the most flak, which seems unfair as the teardowns we've seen clearly show that the phased-array antenna in the Starlink dish is being sold for less than it costs to build. But still, Musk is assuring the world that Starlink home terminals will get down in the $250 to $300 range soon, and that the system could have 500,000 users within a year. There were a couple of other interesting insights, such as where Musk sees Starlink relative to 5G, and how he's positioning Starlink to provide backhaul services to cellular companies.

Well, this is embarrassing. Last week, we mentioned that certain unlucky users of an obsolete but still popular NAS device found that their data had disappeared, apparently due to malefactors accessing the device over the internet and forcing a factory reset. Since this seems like something that should require entering a password, someone took a look at the PHP script for the factory restore function and found that a developer had commented out the very lines that would have performed the authentication:

    function get($urlPath, $queryParams=null, $ouputFormat='xml'){
//        if(!authenticateAsOwner($queryParams))
//        {
//            header("HTTP/1.0 401 Unauthorized");
//            return;
//        }

It's not clear when the PHP script was updated, but support for MyBook Live was dropped in 2015, so this could have been a really old change. Still, it was all the hacker needed to get in and wreak havoc; interestingly, the latest attack may be a reaction to a three-year-old exploit that turned many of these devices into a botnet. Could this be a case of hacker vs. hacker?

#hackadaycolumns #hackadaylinks #3d #collapse #echolocation #espionage #florida #phasedarray #rescue #sdr #spy #starlink #urban

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2018-09-26

What looks like magic 🧙‍♂️ is basically all about manipulating air pressure in a 3D area using the interference of lots of ultrasonic speakers 🔈🔈same as project Open Source Ultrasonic Phased Array by @FauthNiklas hackaday.io/project/159467-ope #PhasedArray source: twitter.com/hackaday/status/10

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