Slow-scan television
Narrowband still picture transmission for amateur radio.
Last updated
Slow-scan television (SSTV) is a method for transmitting still images over narrow-bandwidth channels, introduced by Copthorne Macdonald in 1957–58.[1] Luna 3 employed SSTV to send back pictures from the Moon's hidden hemisphere.[2]
Quick Facts
- Introduced by
- Copthorne Macdonald
- Year introduced
- 1957–58
- Bandwidth
- up to 3 kHz
- Transmission time range
- 8 seconds to a couple of minutes
- Common modes
- Martin M1 (114 seconds), Scottie S1 (110 seconds)
- First live tests band
- 11-meter ham band
- Fcc legalization year
- 1968
Facts from the source article.
Key facts and history
A similar SSTV concept was used on the Faith 7 spacecraft, transmitting one frame every two seconds with a resolution of 320 lines.[3] An image transfer using Martin M1 takes 114 seconds, while Scottie S1 takes 110 seconds.[4] Copthorne Macdonald introduced the SSTV concept in 1957–58 and built the first apparatus, which incorporated an electrostatic monitor and a vidicon tube.[1] The SSTV equipment employed by NASA in its early Apollo missions is very different from the SSTV gear currently operated by amateur radio hobbyists.[5]
The Robot Research Corporation SSTV unit originally had the Scottie and Martin modes added as ROM upgrades.[6]
What the cited sources add
The article "Some Thoughts on 'Real-Time' SSTV Processing" by Cordesses describes a digital SSTV demodulator using linear signal processing and the Hough transform for line estimation.[7] That same article includes the exact timings of the Martin M1 mode, provided by G3OQD.[7] On 3 March 2010, an internet update was released for Valve's 2007 game Portal that added hidden radios whose signals could be decoded as SSTV images.[8]
References
- Wikipedia, "Slow-scan television" (CC BY-SA 4.0), which cites: "Copthorne Macdonald's Home Page", January 2, 2014; Miller, Don, "SSTV history" (original not read by us) en.wikipedia.org
- Wikipedia, "Slow-scan television" (CC BY-SA 4.0), which cites: Luna 3 . . (original not read by us) en.wikipedia.org
- Wikipedia, "Slow-scan television" (CC BY-SA 4.0), which cites: Sven Grahn, "The Mercury-Atlas-9 slow-scan TV experiment", Space Radio Notes; Sven Grahn, "The Mercury-Atlas-9 slow-scan TV experiment", Space Radio Notes (original not read by us) en.wikipedia.org
- Wikipedia, "Slow-scan television" (CC BY-SA 4.0), which cites: Langner, John, "SSTV Transmission Modes." (original not read by us) en.wikipedia.org
- Wikipedia, "Slow-scan television" (CC BY-SA 4.0), which cites: Andrew Letten, "'Lost' Apollo 11 Moonwalk tapes restored", Cosmos Online, 2010-10-26; Peltzer, "Apollo Unified S-Band System", April 1966 (original not read by us) en.wikipedia.org
- Wikipedia, "Slow-scan television" (CC BY-SA 4.0), which cites: Cordesses, L. and R (F2DC), ""Some Thoughts on "Real-Time" SSTV Processing."", QEX, 2003 (we also read that source) en.wikipedia.org
- Cordesses, L. and R (F2DC), ""Some Thoughts on "Real-Time" SSTV Processing."", QEX, 2003. facts only, no text reused. lionel.cordesses.free.fr
- Wikipedia, "Slow-scan television" (CC BY-SA 4.0), which cites: Leahy, "Portal Patch Adds Morse Code, Achievement – Portal 2 Speculation Begins", Shacknews, 2010-03-01; Mastrapa, "Geeky Clues Suggest Portal Sequel Is Coming", 2010-03-02; Gaskill, "Rumor: Valve To Make Portal 2 Announcement During GDC 2010", X-Play, 2010-03-03 (we also read that source) en.wikipedia.org
Each numbered sentence above was checked against the source it cites before publication. Sentences citing Wikipedia adapt text from the English Wikipedia article Slow-scan television (contributors), used under CC BY-SA 4.0; this entry is available under the same licence. Other sources were used for facts only; no text or images are copied from them.
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Sources
Compiled from Wikipedia and the sources listed below. Text from Wikipedia is available under CC BY-SA 4.0; this entry is adapted from it.
- Wikipedia: Slow-scan television (CC BY-SA 4.0).
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