Analyzing Starlink Satellite Downlink Communications With Software Defined Radio
Often simple curiosity is enough to do something. This is also the case with people trying to analyze the communication setup and protocol that SpaceX uses with its Ku-band based Starlink satellites. He is one of these nice people [Christian Hahn]which is recent published some early findings to r / StarlinkEngineering in Reddit. Some of the captured data appears to include a satellite identification system that terrestrial consumer stations would likely use to track Starlink satellites from above.
For the shooting itself, [Christian] uses a second-hand capture antenna and DIY SDR using the KC705 FPGA-based hardware – which may have started life as crypto-digging hardware – along with the usual range of filters and other common components with this type of capture. Even at this early time, some features of the Starlink protocol seem quite obvious, such as channel separation and the use of protection periods. Nothing too shocking, but as a fun SDR hobby it definitely puts all the ticks in the boxes.
[Christian] also announced that at some point it will create a website and publish findings and code that should make Starlink signal analysis easy for anyone with an easily accessible SDR receiver.