Ground Sphere Mk 3

h1. Similar Projects

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The following is a list of other low cost satellite receiving projects.  Not all projects are open source hardware, but all include at least some degree of documentation/evidence of success.  Note, some of these projects require the use of a directional antenna (usually a hand held "Yagi":https://en.wikipedia.org/wiki/Yagi-Uda_antenna) to provide sufficient gain.  Contrast this with the Ground Sphere goal of providing a new user friendly system by utilizing an omni-directional antenna.

h2. "Listening to a Satellites for 30 Dollars":http://blog.nobugware.com/post/2015/listening_to_satellites_for_30_dollars/

Basic instructions for receiving 1990s era weather satellite data.  Utilizes SDR USB dongle and free (mostly open source) software.  Lowest cost example that does not strictly require Yagi antenna (post does not spend much time discussing the antenna).  There is a PBI in Sprint 1 to attempt to reproduce the results of this post at one or more Mach 30 volunteer sites.

h2. "KickSat Ground Station":https://github.com/kicksat/groundstation/wiki

Hand-held Yagi + SDR based ground station for receiving telemetry from "KickSat sprites":https://www.kickstarter.com/projects/zacinaction/kicksat-your-personal-spacecraft-in-space.  This is an open source hardware project published on GitHub. 

h2. "How to Hear the ISS":http://amsat-uk.org/beginners/how-to-hear-the-iss/

AMSAT-UK blog post on using ham radio gear to listen to the ISS.  Discussion includes antenna selection (a "1/4 wave whip antenna":https://en.wikipedia.org/wiki/Whip_antenna and a "1/4 wave ground plane":http://www.hamuniverse.com/2metergp.html).  The post mentions 3 things you can listen for from the ISS.

* AX.25 packet repeater

* Voice repeater

* Receive Slow Scan Television (SSTV) pictures

h2. "Receiving Slow Scan TV Images from the International Space Station":http://www.jpole-antenna.com/2015/02/25/receiving-slow-scan-tv-images-from-the-international-space-station/

YouTube video/blog post about using ham radio gear to receive and decode an SSTV picture from the ISS.  As with earlier posts, this operator recommends lower gain antennas for these applications (mostly for omni-directional qualities).  Post includes specific antenna recommendations and includes an example pass of the ISS.  Check it out:

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Need to see if anyone is doing this with SDRs.

h2. "Listening to Satellites on a Handheld Scanner":http://www.instructables.com/id/Listening-to-Satellites-on-a-Handheld-Scanner/?ALLSTEPS

Less instructions and more background.  The antenna section is particularly interesting.

h2. "RTL-SDR Blog Posts About Using RTL2832U to Receive ISS Signals":http://www.rtl-sdr.com/tag/international-space-station/

Tag search for ISS posts on RTL-SDR blog.  Lots of good posts linking to YouTube videos and other blog posts.  This is a goldmine of info and a potential resource to share our work with.  What I don't see here is someone having kit'ified the concept for easy replication by others.