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| {{Short description|Amateur radio communications software}} | {{Short description|Amateur radio communications software}} | ||
| {{Infobox software | {{Infobox software | ||
| | name |
| name = WSPR | ||
| | logo |
| logo = | ||
| | screenshot |
| screenshot = <!-- we need a screenshot --> | ||
| | caption |
| caption = | ||
| | developer |
| developer = ] | ||
| | released |
| released = 2008 | ||
| | programming language |
| programming language = C++ (GUI), Fortran, C <ref>{{Cite web|url=https://wsjt.sourceforge.io/devel.html|title=Program Development and Licensing|website=wsjt.sourceforge.io/devel}}</ref> | ||
| | operating system |
| operating system = ] | ||
| | language |
| language = English, Italian, Spanish, French, German, Japanese, Polish, Portuguese, Russian | ||
| | genre |
| genre = ] and ] | ||
| | license |
| license = ] | ||
| | website = | |||
| | status = active | |||
| | website = | |||
| }} | }} | ||
| '''WSPR''' (pronounced "whisper") is an acronym for ''Weak Signal Propagation Reporter''. It is a protocol, implemented in a computer program, used for weak-] ] between ] ]. The protocol was designed, and a program written initially, by ]. The software code is now ] and is developed by a small team. The program is designed for sending and receiving low-power transmissions to test propagation paths on the ] and ] bands. | '''WSPR''' (pronounced "whisper") is an acronym for '''Weak Signal Propagation Reporter'''. It is a protocol, implemented in a computer program, used for weak-] ] between ] ]. The protocol was designed, and a program written initially, by ]. The software code is now ] and is developed by a small team. The program is designed for sending and receiving low-power transmissions to test propagation paths on the ] and ] bands. | ||
| WSPR implements a protocol designed for probing potential propagation paths with low-power transmissions. Transmissions carry a station's callsign, ], and transmitter power in ]. The program can decode signals with a ] as low as −28 dB in a 2500 Hz bandwidth.<ref>{{Cite web|url=https:// |
WSPR implements a protocol designed for probing potential propagation paths with low-power transmissions. Transmissions carry a station's callsign, ], and transmitter power in ]. The program can decode signals with a ] as low as −28 dB in a 2500 Hz bandwidth.<ref>{{Cite web |title=WSJT Home Page |url=https://wsjt.sourceforge.io/ |website=WSJT Home Page}}</ref> Stations with internet access can automatically upload their reception reports to a central database called WSPRnet, which includes a mapping facility. | ||
| ==The WSPR Protocol== | ==The WSPR Protocol== | ||
| The ] is “F1D”, ]. | The ] is “F1D”, ]. | ||
| A message contains a station's callsign, ], and transmitter power in ].<ref name="k1jt">Joe Taylor, K1JT: WSPRing Around the World. QST November (2010), p. 30-32.</ref> | A message contains a station's callsign, ], and transmitter power in ].<ref name="k1jt">Joe Taylor, K1JT: WSPRing Around the World. QST November (2010), p. 30-32.</ref> | ||
| The WSPR protocol compresses the information in the message into 50 ]s (binary digits). These are encoded using a ] with constraint length ''K'' = 32 and a rate of ''r'' = {{frac|1|2}}.<ref name="k1jt"/><ref> |
The WSPR protocol compresses the information in the message into 50 ]s (binary digits). These are encoded using a ] with constraint length ''K'' = 32 and a rate of ''r'' = {{frac|1|2}}.<ref name="k1jt"/><ref>{{Cite web|url=http://www.g4jnt.com/Coding/WSPR_Coding_Process.pdf|title=G4JNT: The WSPR Coding Process: Non-normative specification of WSPR protocol}}</ref> | ||
| The long constraint length makes undetected decoding errors less probable, at the cost that the highly efficient ] must be replaced by a simple sequential algorithm for the decoding process.<ref name="k1jt"/> | The long constraint length makes undetected decoding errors less probable, at the cost that the highly efficient ] must be replaced by a simple sequential algorithm for the decoding process.<ref name="k1jt"/> | ||
| ===Protocol specification=== | ===Protocol specification=== | ||
| The standard message is <callsign> + <4 character locator> + <dBm transmit power>; for example “K1ABC FN20 37” is a signal from station K1ABC in ] cell “FN20”, sending |
The standard message is <callsign> + <4 character locator> + <dBm transmit power>; for example “K1ABC FN20 37” is a signal from station K1ABC in ] cell “FN20”, sending 37 dBm, or about 5.0 W (legal limit for ]). | ||
| Messages with a compound callsign and/or 6 digit locator use a two-transmission sequence. The first transmission carries compound callsign and power level, or standard callsign, 4 digit locator, and power level; the second transmission carries a hashed callsign, 6 digit locator, and power level. Add-on prefixes can be up to three alphanumeric characters; add-on suffixes can be a single letter or one or two digits. | Messages with a compound callsign and/or 6 digit locator use a two-transmission sequence. The first transmission carries compound callsign and power level, or standard callsign, 4 digit locator, and power level; the second transmission carries a hashed callsign, 6 digit locator, and power level. Add-on prefixes can be up to three alphanumeric characters; add-on suffixes can be a single letter or one or two digits. | ||
| * Fields of a standard message: | |||
| * Standard message components after lossless compression: | |||
| :28 bits for callsign, | :28 bits for callsign, | ||
| :15 bits for locator, | :15 bits for locator, | ||
| : |
: 5 bits for power level, | ||
| : 2 bits for message type, | |||
| :total: 50 bits. | :total: 50 bits. | ||
| * Forward error correction (FEC): | * Forward error correction (FEC): | ||
| Line 62: | Line 62: | ||
| An accurate clock is essential both for transmission and decoding of received signals. | An accurate clock is essential both for transmission and decoding of received signals. | ||
| ===MH370=== | ===MH370 hypothesis=== | ||
| In May 2021, |
In May 2021, aerospace engineer Richard Godfrey suggested examining historical WSPR data as a way to define the flight path of ] on 8 March 2014.<ref name="2021-05-05_ABC">, Anne Barker, ], 2021-05-05</ref> In November 2021, Godfrey stated his belief that his analysis indicates the aircraft flew in circles for around 22 minutes in an area {{convert|150|nmi}} from the coast of ] before vanishing, later proposing a search area centered around {{coord|33.177|S|95.3|E}}.<ref>{{Cite news|last=Browning|first=Simon|date=3 December 2021|title=MH370: Could missing Malaysian Airlines plane finally be found?|work=]|url=https://www.bbc.com/news/business-59517821|access-date=27 January 2022}}</ref><ref>{{Cite web |last=Thomas |first=Geoffrey |date=2021-09-07 |title=Breakthrough technology giving real hope for a new search for MH370 |url=https://www.airlineratings.com/news/breakthrough-technology-giving-real-hope-for-a-new-search-for-mh370/ |access-date=2023-05-16 |website=Airline Ratings |language=en-AU}}</ref><ref>{{Cite web |last=Thomas |first=Geoffrey |date=2022-06-25 |title=MH370 TRACKING EXPERT DEMONSTRATES HIS TECHNOLOGY ONCE AGAIN |url=https://www.airlineratings.com/news/industry-news/mh370-tracking-expert-demonstrates-technology/ |access-date=2023-05-16 |website=Airline Ratings |language=en-AU}}</ref><ref>{{Cite web |last=Thomas |first=Geoffrey |date=2022-10-28 |title=MH370: New Research Paper Confirms WSPRnet Tracking Technology |url=https://www.airlineratings.com/news/mh370-new-research-paper-confirms-wsprnet-tracking-technology/ |access-date=2023-05-16 |website=Airline Ratings |language=en-AU}}</ref> | ||
| As of March 2024, the validity of Godfrey's claim is yet to be established.<ref>{{Cite web |last=Thomas |first=Geoffrey |date=2022-11-02 |title=MH370 New Location Critics Sunk |url=https://www.airlineratings.com/news/critics-of-wsprnet-tracking-mh370-been-answered/ |access-date=2023-05-16 |website=Airline Ratings |language=en-AU}}</ref> | |||
| On 6 March 2024 the BBC documentary ''Why Planes Vanish: The Hunt for MH370'' examined Godfrey's claim and reported that scientists at the ] were undertaking an analytical study of the possibility of using WSPR technology to locate the missing aircraft. The University stated they would release their results within 6 months.<ref>{{Cite web|url=https://www.bbc.co.uk/iplayer/episode/m001x0yh/why-planes-vanish-the-hunt-for-mh370|title=Why Planes Vanish: The Hunt for MH370|via=www.bbc.co.uk}}</ref><ref>{{cite news |url=https://www.independent.co.uk/travel/news-and-advice/mh370-radio-signals-theory-bbc-doc-b2508628.html |title=Could disrupted radio signals locate MH370? Theory is examined in new documentary |last=Wilson |first=Natalie |work=The Independent |date=7 March 2024 |access-date=8 March 2024}}</ref> | |||
| ==History== | ==History== | ||
| Line 79: | Line 80: | ||
| * | * | ||
| == Further reading == | |||
| {{Digital modes}} | |||
| (Self-published, Dropbox){{Digital_modes|state=collapsed}} | |||
| {{Two-way_radio|state=collapsed}} | |||
| {{Amateur radio topics|state=collapsed}} | |||
| {{Telecommunications|state=collapsed}} | |||
| ] | ] | ||
Latest revision as of 17:52, 12 December 2024
Amateur radio communications software| Developer(s) | Joe Taylor, K1JT |
|---|---|
| Initial release | 2008 |
| Written in | C++ (GUI), Fortran, C |
| Operating system | Cross-platform |
| Available in | English, Italian, Spanish, French, German, Japanese, Polish, Portuguese, Russian |
| Type | Amateur radio and DSP |
| License | GPL |
| Website | wsjt.sourceforge.io |
WSPR (pronounced "whisper") is an acronym for Weak Signal Propagation Reporter. It is a protocol, implemented in a computer program, used for weak-signal radio communication between amateur radio operators. The protocol was designed, and a program written initially, by Joe Taylor, K1JT. The software code is now open source and is developed by a small team. The program is designed for sending and receiving low-power transmissions to test propagation paths on the MF and HF bands.
WSPR implements a protocol designed for probing potential propagation paths with low-power transmissions. Transmissions carry a station's callsign, Maidenhead grid locator, and transmitter power in dBm. The program can decode signals with a signal-to-noise ratio as low as −28 dB in a 2500 Hz bandwidth. Stations with internet access can automatically upload their reception reports to a central database called WSPRnet, which includes a mapping facility.
The WSPR Protocol
The type of radio emission is “F1D”, frequency-shift keying. A message contains a station's callsign, Maidenhead grid locator, and transmitter power in dBm. The WSPR protocol compresses the information in the message into 50 bits (binary digits). These are encoded using a convolutional code with constraint length K = 32 and a rate of r = 1⁄2. The long constraint length makes undetected decoding errors less probable, at the cost that the highly efficient Viterbi algorithm must be replaced by a simple sequential algorithm for the decoding process.
Protocol specification
The standard message is <callsign> + <4 character locator> + <dBm transmit power>; for example “K1ABC FN20 37” is a signal from station K1ABC in Maidenhead grid cell “FN20”, sending 37 dBm, or about 5.0 W (legal limit for 630 m). Messages with a compound callsign and/or 6 digit locator use a two-transmission sequence. The first transmission carries compound callsign and power level, or standard callsign, 4 digit locator, and power level; the second transmission carries a hashed callsign, 6 digit locator, and power level. Add-on prefixes can be up to three alphanumeric characters; add-on suffixes can be a single letter or one or two digits.
- Fields of a standard message:
- 28 bits for callsign,
- 15 bits for locator,
- 5 bits for power level,
- 2 bits for message type,
- total: 50 bits.
- Forward error correction (FEC):
- non-recursive convolutional code with constraint length K = 32, rate r = 1⁄2.
- Number of binary channel symbols:
- nsym = (50 + K − 1) × 2 = 162.
- Keying rate is 12000⁄8192 = 1.4648 baud.
- Modulation is continuous phase 4 FSK, with 1.4648 Hz tone separation.
- Occupied bandwidth is about 6 Hz
- Synchronization is via a 162 bit pseudo-random sync vector.
- Each channel symbol conveys one sync bit (LSB) and one data bit (MSB).
- Duration of transmission is 162 × 8192⁄12000 = 110.6 s.
- Transmissions nominally start one second into an even UTC minute: e.g., at hh:00:01, hh:02:01, etc.
- Minimum S/N for reception is around –34 dB on the WSJT scale (2500 Hz reference bandwidth).
Applications
The protocol was designed to test propagation paths on the LF, MF and HF bands. Also used experimentally at VHF and higher frequencies.
Other applications include antenna testing, frequency stability and frequency accuracy checking.
Usually a WSPR station contains a computer and a transceiver, but it is also possible to build very simple beacon transmitters with little effort.
For example a simple WSPR beacon can be built using the Si 570, or Si 5351. The Raspberry Pi can also be used as WSPR beacon.
An accurate clock is essential both for transmission and decoding of received signals.
MH370 hypothesis
In May 2021, aerospace engineer Richard Godfrey suggested examining historical WSPR data as a way to define the flight path of Malaysia Airlines Flight 370 on 8 March 2014. In November 2021, Godfrey stated his belief that his analysis indicates the aircraft flew in circles for around 22 minutes in an area 150 nautical miles (280 km; 170 mi) from the coast of Sumatra before vanishing, later proposing a search area centered around 33°10′37″S 95°18′00″E / 33.177°S 95.3°E / -33.177; 95.3.
As of March 2024, the validity of Godfrey's claim is yet to be established. On 6 March 2024 the BBC documentary Why Planes Vanish: The Hunt for MH370 examined Godfrey's claim and reported that scientists at the University of Liverpool were undertaking an analytical study of the possibility of using WSPR technology to locate the missing aircraft. The University stated they would release their results within 6 months.
History
WSPR was originally released in 2008.
References
- "Program Development and Licensing". wsjt.sourceforge.io/devel.
- "WSJT Home Page". WSJT Home Page.
- ^ Joe Taylor, K1JT: WSPRing Around the World. QST November (2010), p. 30-32.
- "G4JNT: The WSPR Coding Process: Non-normative specification of WSPR protocol" (PDF).
- WSPR Beacon with Si 570 and Atmel AVR http://wsprnet.org/drupal/sites/wsprnet.org/files/si570wspr.pdf
- QRSS/WSPR Transmitter Kit https://qrp-labs.com/
- Malaysia Airlines flight MH370 left 'false trails' before disappearing, new research suggests, Anne Barker, ABC News Online, 2021-05-05
- Browning, Simon (3 December 2021). "MH370: Could missing Malaysian Airlines plane finally be found?". BBC. Retrieved 27 January 2022.
- Thomas, Geoffrey (2021-09-07). "Breakthrough technology giving real hope for a new search for MH370". Airline Ratings. Retrieved 2023-05-16.
- Thomas, Geoffrey (2022-06-25). "MH370 TRACKING EXPERT DEMONSTRATES HIS TECHNOLOGY ONCE AGAIN". Airline Ratings. Retrieved 2023-05-16.
- Thomas, Geoffrey (2022-10-28). "MH370: New Research Paper Confirms WSPRnet Tracking Technology". Airline Ratings. Retrieved 2023-05-16.
- Thomas, Geoffrey (2022-11-02). "MH370 New Location Critics Sunk". Airline Ratings. Retrieved 2023-05-16.
- "Why Planes Vanish: The Hunt for MH370" – via www.bbc.co.uk.
- Wilson, Natalie (7 March 2024). "Could disrupted radio signals locate MH370? Theory is examined in new documentary". The Independent. Retrieved 8 March 2024.
External links
Further reading
GDTAAA WSPRnet MH370 Analysis Flight Path Report (Self-published, Dropbox)
| Amateur radio digital modes | ||
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| Frequency-shift keying (FSK) |  | |
| Multiple frequency-shift keying (MFSK) | ||
| Phase-shift keying (PSK) | ||
| COFDM |
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