[HN Gopher] Detecting Starlink Satellites with a Portable Raspbe...
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       Detecting Starlink Satellites with a Portable Raspberry Pi and RTL-
       SDR (2022)
        
       Author : ctoth
       Score  : 65 points
       Date   : 2023-03-03 19:47 UTC (3 hours ago)
        
 (HTM) web link (www.rtl-sdr.com)
 (TXT) w3m dump (www.rtl-sdr.com)
        
       | sgtnoodle wrote:
       | I always bring this up in the hope that it's seen by someone that
       | has deep knowledge on the subject. The Raspberry Pi's USB 2.0
       | implementation seems to be horribly inefficient. An RTL-SDR uses
       | over 40% of a CPU core on a Pi 4 just doing USB transfers. It's
       | less than 5% on a typical laptop, as well as on other aarch64
       | SoMs such as Nvidia Xavier. What's going on? Is the peripheral
       | itself just really cheesy? Is the driver not using DMA when it
       | could be?
        
       | nimbius wrote:
       | wild. does anyone know if linear polarization is specific to
       | starlink? youd imagine a circular polarization would make for
       | better reception over all.
       | 
       | the second example in the video may have failed as the
       | directionality/alignment of the LNB and the use of a parabolic
       | dish are typically encouraged for best satellite reception
       | results. a Dish TV or direcTV setup for about $10 at a junkyard
       | might outperform? i dont think these "branded" setups are as
       | discrete or fine tuned as the author suggests.
       | 
       | https://www.reddit.com/r/Starlink/comments/s83ahf/using_dire...
       | 
       | ive been using PI and RTL/SDR to decode ADS-B for about a year
       | now and i gotta say the temperature issues aside it works a
       | treat. just waiting to see ole muskys jet pop up at some point ;)
        
       | CliffStoll wrote:
       | Absolutely sweet!
       | 
       | What a delight to see a rasp-pi enthusiast mix satellite
       | detection with antenna design and junk box hacking!
       | 
       | Long ago, this was the ham radio mindset... still is, for some.
        
         | lxgr wrote:
         | Speaking of ham radio mindset, I'm continuously amazed by the
         | existence of VHF and UHF amateur radio relay satellites, as
         | well as the ham station on the ISS.
         | 
         | It doesn't seem like pointing a handheld radio at the sky could
         | possibly be enough to talk to astronauts, yet it seems to work!
        
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       (page generated 2023-03-03 23:00 UTC)