Over on YouTube, Stephen Ong has posted a video of his standalone Terratec RTL-SDR and BeagleBone Black based spectrum analyzer. What makes this unique is the lack of computer needed and dedicated 7 inch touch LCD screen (CircuitCo LCD7 cape). Powered by 6 AA batteries, the unit is nice and portable. BeagleBoards are low-cost, fan-less single-board computers based on low-power Texas Instruments processors featuring the ARM Cortex-A8 core. The BeagleBone Black DevKit used in the video costs around USD$50. He demonstrates the unit showing the RF spectrum of commercial FM stations, car remote transmitters, analog TV (PAL B) broadcast, DVB-T broadcast, cellular GSM900 and a DECT cordless phone.
Travis Goodspeed has shared a project on his blog about his adventure in tracking low orbit satellites using a fairly complex setup. He is using a dish intended for connecting to one of the Inmarsat satellites while at sea on a maritime vessel, a EiBotBoard connected to a BeagleBone for motor control and a RTL-SDR for receiving radio signals from the dish. His goal has been to track the whole sky, including moving targets and it looks like he has been pretty successful.
“At Black Hat DC in 2008, I watched Adam Laurie present a tool for mapping Ku-band satellite downlinks, which he has since rewritten as Satmap. His technique involves using an DVB-S card in a Linux computer as a receiver through a 90cm Ku-band dish with fixed elevation and a DiSEqC motor for azimuth motion. It was among the most inspirational talks I’d ever seen, and I had a blast recreating his setup and scanning the friendly skies. However, such a rig is limited to geostationary satellites in a small region of the sky; I wanted to see the whole sky, especially the moving targets.
In this article, I’ll demonstrate a method for modifying a naval telecommunications dish to track moving targets in the sky, such as those in Low Earth Orbit. My dish happily sits in Tennessee, while I direct it using my laptop or cellphone here in Europe. It can also run unattended, tracking moving targets and looking for downlink channels.” — Travis Goodspeed