Desktop Radio Telescope Images The WiFi Universe

June 20, 2018 by Dan Maloney 21 Comments

It’s been a project filled with fits and starts, and it very nearly ended up as a “Fail of the Week” feature, but we’re happy to report that the [Thought Emporium]’s desktop WiFi radio telescope finally works. And it’s pretty darn cool.

If you’ve been following along with the build like we have, you’ll know that this stems from a previous, much larger radio telescope that [Justin] used to visualize the constellation of geosynchronous digital TV satellites. This time, he set his sights closer to home and built a system to visualize the 2.4-GHz WiFi band. A simple helical antenna rides on the stepper-driven azimuth-elevation scanner. A HackRF SDR and GNU Radio form the receiver, which just captures the received signal strength indicator (RSSI) value for each point as the antenna scans. The data is then massaged into colors representing the intensity of WiFi signals received and laid over an optical image of the scanned area. The first image clearly showed a couple of hotspots, including a previously unknown router. An outdoor scan revealed routers galore, although that took a little more wizardry to pull off.

The videos below recount the whole tale in detail; skip to part three for the payoff if you must, but at the cost of missing some valuable lessons and a few cool tips, like using flattened pieces of Schedule 40 pipe as a construction material. We hope to see more from the project soon, and wonder if this FPV racing drone tracker might offer some helpful hints for expansion.

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Paul Horowitz And The Search For Extra Terrestrial Intelligence

July 19, 2017 by Gregory L. Charvat 91 Comments

I recently had the opportunity to attend a lecture by Harvard Professor Paul Horowitz. It’s a name you likely recognize. He is best known for his iconic book the Art of Electronics which is often referred to not by its name but by the last names of the authors: “Horowitz and Hill”.

Beyond that, what do you know about Paul Horowitz? Paul is an electrical engineer and physicist and Paul has spent much of his storied career learning and practicing electronics for the purpose of finding intelligent extra terrestrial life.

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See Satellites With A Simple Radio Telescope

March 23, 2017 by Dan Maloney 17 Comments

Have you got a spare Dish Network antenna lying about? They’re not too hard to come by, either curbside on bulk waste day or perhaps even on Freecycle. If you can lay hands on one, you might want to try this fun radio telescope build.

Now, don’t expect much from [Justin]’s minimalist build. After all, you’ll be starting with a rather small dish and an LNB for the Ku band, so you won’t be doing serious radio astronomy. In fact, the BOM doesn’t include a fancy receiver – just a hacked satellite finder. The idea is to just get a reading of the relative “brightness” of a radio source without trying to demodulate the signal. To that end, the signal driving the piezo buzzer in the sat finder is fed into an Arduino through a preamp. The Arduino also controls stepper motors for the dish’s azimuth and elevation control, which lets it sweep the sky and build up a map of signal intensity. The result is a clear band of bright spots representing the geosynchronous satellites visible from [Justin]’s location in Brazil.

Modifications are definitely on the docket for [Justin], including better equipment that will allow him to image the galactic center. There may be some pointers for him in our coverage of a tiny SDR-based radio telescope, or from this custom receiver that can listen to Jupiter.

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Listen To The Sun, Saturn, And The Milky Way With Your Own Radio Telescope

September 28, 2016 by Al Williams 4 Comments

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.

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The Tiny Radio Telescope

July 31, 2016 by Jenny List 40 Comments

Radio telescopes are one of the more high-profile pieces of scientific apparatus. There is an excitement to stories of radio astronomers of old probing the mysteries of the Universe on winter nights in frigid cabins atop massive parabolas, even if nowadays their somewhat more fortunate successors do the same work from the comfort of their labs using telescopes that may be on the other side of the world.

You might think if you look at the Arecibo Observatory, Lovell Telescope, or other famous pieces of apparatus, that this is Big Science, out of reach for mere mortals such as yourself without billion-dollar research programs. Maybe [Paul Scott] and [Allen Versfeld]’s Tiny Radio Telescope project will change that view.

The NRAO published a radio telescope design a few years ago for use mainly as an educational tool, the Itty Bitty Telescope. It used a satellite TV dish and LNB feeding a signal meter as a simple telescope to detect the Sun, and black body radiation from the surrounding objects. It’s a simple design for kids to get their heads around, and [Scott] and [Allen] have set out to turn it into something more useful with an RTL-SDR instead of a signal meter and a motorised mount for automated observations.

This is one of those projects on Hackaday.io that moves slowly but you know will eventually deliver on its promise. With a 1m dish and a consumer LNB it’s never going to make a discovery that will rock the world, but that’s not the point. It may be science that the astrophysicists moved on from decades ago, but it’s still quite an achievement that the radio sky can be imaged using such mundane equipment.

We’ve featured backyard radio astronomy before a few times, from this UHF school science project to another satellite TV based telescope. Keep them coming!

A thank you to Southgate ARC for the prod.

Hackaday Links: Sunday, June 2nd, 2013

June 2, 2013 by Mike Szczys 15 Comments

Who knew you could build your own digital computer out of paperclips? EMSL did a great feature on the guide which was published in 1968.

Trying to keep your Raspberry Pi from overheating? Make it log its core temperature on the web.

[Lennart] must be some kind of Eagle CAD guru. Check out these PCBs that incorporate his logo in a very artsy way.

No need for a tripod when you can just strap the video camera to your safety glasses for some POV project videos.

Turn your Pogoplug E-02 into a Shairport (Airplay clone) music hub. Just follow this guide which installs Arch Linux and all the supporting packages you need.

We don’t have the background to judge the quality of this build. But you have to admit it’s pretty neat to see a radio telescope built using a tin can and an umbrella.

Dead rodent email: get a notification every time your mouse trap springs.

Detecting Galactic Rotation With Software Defined Radio

May 26, 2013 by Brian Benchoff 27 Comments

Last summer in the heyday of software defined radio via USB TV tuners we asked hackaday readers a question: Is anyone using everyone’s favorite method of SDR for radio astronomy? It took nearly a year, but finally there’s an awesome project to turn a USB TV tuner into a radio telescope. It’s from the fruitful mind of [Marcus Leech] (PDF warning), and is good enough to detect the rotation of the galaxy with a three-foot satellite dish.

News of [Marcus]’ work comes to us from [Carl] over at RTL-SDR.com who has been keeping tabs on the advances of building a radio telescope in a backyard. He’s been collecting a lot of interesting tidbits including this gif showing an arm of the galaxy entering and leaving [Marcus]’ telescope’s field of view over the course of a few hours.

Not only can [Marcus]’ telescope record continium measurements – basically, a single-pixel camera sensitive to only one frequency – it can also produce spectral plots of the sky. Combine the ability to measure multiple frequencies at the same time with the Doppler effect, and [Marcus] can measure the rotation of the galaxy with a USB TV tuner. That’s just awesome in our humble opinion.

If you already have an RTL-SDR TV tuner and a largish satellite dish, [Marcus]’ project should be fairly inexpensive to replicate; the feed assembly is made out of a coffee can, the amplifiers are repurposed satellite television equipment, and all the software – [Marcus]’ own simple_ra tool for GNU Radio – is open source. Of course with a 3 foot diameter dish, it will be impossible to replicate the data from huge radio telescopes. Still, it’s an impressive piece of work that leaves us searching craigslist for an old C-band dish.