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.