WSPR (amateur radio software): Difference between revisions

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	{{Short description\|Amateur radio communications software}}		{{Short description\|Amateur radio communications software}}
	{{Infobox software		{{Infobox software
	\| name = WSPR		\| name = WSPR
	\| logo =		\| logo =
	\| screenshot = <!-- we need a screenshot -->		\| screenshot = <!-- we need a screenshot -->
	\| caption =		\| caption =
	\| developer = ]		\| developer = ]
	\| released = 2008		\| released = 2008
	\| programming language = ~~Python~~ (GUI), Fortran, C <ref>{{Cite web\|url=https://~~physics~~.~~princeton~~.~~edu//pulsar/K1JT~~/devel.html\|title=~~WSJT~~ ~~Home~~ ~~Page~~\|website=~~physics~~.~~princeton~~.~~edu~~}}</ref>		\| 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 = English, Italian, Spanish, French, German, Japanese, Polish, Portuguese, Russian		\| language = English, Italian, Spanish, French, German, Japanese, Polish, Portuguese, Russian
	\| genre = ] and ]		\| genre = ] and ]
	\| license = ]		\| license = ]
			\| website =
	\| status = active
	\| website =
	}}		}}

	'''WSPR''' (pronounced "whisper") ~~stands~~ 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://~~physics~~.~~princeton~~.~~edu~~/~~/pulsar/K1JT/wspr.html~~\|~~title~~=WSJT Home Page~~\|website=physics.princeton.edu~~}}</ref> Stations with internet access can automatically upload their reception reports to a central database called WSPRnet, which includes a mapping facility.		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></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 ~~digit~~ locator> + <dBm transmit power>; for example “K1ABC FN20 37” is a signal from station K1ABC in ] cell “FN20”, sending ~~10<sup>3.7</sup>milliwatts~~, or about 5.0 ~~Watts~~ (legal limit for ]).		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,
	: 7 bits for power level,		: 5 bits for power level,
			: 2 bits for message type,
	:total: 50 bits.		:total: 50 bits.
	* Forward error correction (FEC):		* Forward error correction (FEC):
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	:nsym = (50 + K − 1) × 2 = 162.<ref name="k1jt"/>		:nsym = (50 + K − 1) × 2 = 162.<ref name="k1jt"/>
	* Keying rate is {{frac\|12000\|8192}} = 1.4648 baud.		* Keying rate is {{frac\|12000\|8192}} = 1.4648 baud.
	* Modulation is continuous phase 4 ], with 1.4648 Hz tone separation.		* Modulation is continuous phase 4 ], with 1.4648 Hz tone separation.
	]		]
	* Occupied bandwidth is about 6 Hz		* Occupied bandwidth is about 6 Hz
	* Synchronization is via a 162 bit pseudo-random sync vector.		* Synchronization is via a 162 bit pseudo-random sync vector.
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	* Duration of transmission is 162 × {{frac\|8192\|12000}} = 110.6 s.		* Duration of transmission is 162 × {{frac\|8192\|12000}} = 110.6 s.
	* Transmissions nominally start one second into an even ] minute: e.g., at hh:00:01, hh:02:01, etc.		* Transmissions nominally start one second into an even ] minute: e.g., at hh:00:01, hh:02:01, etc.
	* Minimum ] for reception is around –34 dB on the ] scale (2500 Hz reference bandwidth).		* Minimum ] for reception is around –34 dB on the ] scale (2500 Hz reference bandwidth).

	==Applications==		==Applications==
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	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===
	In May 2021, ] Richard Godfrey suggested an examination of historical WSPR data to further define the flight path of ] on 8 March 2014, suggesting that there were "518 unique transmission paths that cross the area of interest around Malaysia, the Malacca Strait and the Indian Ocean. With the WSPR data provided every two minutes and the ability to check against the satellite data every hour it is possible to detect and track MH370 from two independent sources."<ref name=”2021-05-05_ABC”>, Anne Barker, ], 2021-05-05</ref> In November 2021, Godfrey reported that analysis using WSPR technology indicated the aircraft flew in circles for around 22 minutes in an area 150 nautical miles from the coast of ] before vanishing.<ref>{{cite news\|date=November 10, 2021\|title=Engineer says doomed MH370 plane 'flew in circles for 20 mins before vanishing'\|newspaper=New York Post\|url=https://nypost.com/2021/11/10/engineer-says-doomed-mh370-plane-flew-in-circles-for-20-mins-before-vanishing/}}</ref> Later that month, Godfrey announced a proposed search area with a radius of {{convert\|40.0\|nmi\|km}} centered around 33.177°S 95.300°E in the southern ]. This new location was identified through extensive analysis of separate data sets, including ] satellite data, Boeing performance data, oceanographic floating debris drift data, and WSPR net data.<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 \|title=GDTAAA WSPRnet MH370 Analysis Flight Path Report.pdf \|url=https://www.dropbox.com/s/k4fn8eec4z9np0z/GDTAAA%20WSPRnet%20MH370%20Analysis%20Flight%20Path%20Report.pdf \|access-date=6 March 2022 \|website=Dropbox}}</ref>

		⚫	===MH370 hypothesis===
	In February 2022, the ] and ] confirmed they have renewed the search for MH370 by reviewing old data, following the release of a detailed report by Godfrey.<ref>{{Cite news\|last=Ransley\|first=Ellen\|date=16 February 2022\|title=New technology could hold key to MH370 disappearance\|work=]\|url=https://www.news.com.au/travel/travel-updates/incidents/new-technology-could-hold-key-to-mh370-disappearance/news-story/cd49b64358cd87b2828fb0b494ec772d\|access-date=17 February 2022}}</ref> Marine robotics company ] aims to resume the search for MH370 in the first half of 2023.<ref>{{Cite news \|last=Richards \|first=Isabella \|date=8 March 2022 \|title=Search for MH370 to Resume in 2023 \|work=] \|url=https://australianaviation.com.au/2022/03/search-for-mh370-to-resume-in-2023/ \|access-date=8 March 2022}}</ref>
			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>
⚫	== History ==
			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==
	WSPR was originally released in 2008.		WSPR was originally released in 2008.
	<!-- Poss. add'l topics: history? popularity? importance to amateur radio -- particularly WRT small-gun EME stations? Also: deep search "controversy"? (are there sources for that?) -->		<!-- Poss. add'l topics: history? popularity? importance to amateur radio -- particularly WRT small-gun EME stations? Also: deep search "controversy"? (are there sources for that?) -->
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	* {{Official website}}		* {{Official website}}
	*		*
	*
	*
	*		*

			== 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

WSPR
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.

v t e Amateur radio digital modes
Frequency-shift keying (FSK)	RTTY AMTOR / SITOR PACTOR CLOVER2000 Packet radio (Bell 103 Bell 202) M17
Multiple frequency-shift keying (MFSK)	Olivia MFSK Contestia JT65 FSK441 JT6M WSPR FT8
Phase-shift keying (PSK)	PSK31 PSK63 Q15X25
COFDM	MT63 (based on PSK)
Non-traditional digital modes	Hellschreiber (Feld-Hell) On–off keying Continuous wave Modulated continuous wave Pulse modulation Frequency-hopping spread spectrum (FHSS) Direct-sequence spread spectrum (DSSS) AMPRNet DAPNET

v t e Two-way radio
Amateur and hobbyist	Amateur radio Amateur radio repeater Citizens band radio Family Radio Service Public Radio Service General Mobile Radio Service KDR 444 LPD433 Mobile rig Multi-Use Radio Service PMR446 UHF CB (Australia)
Aviation (aeronautical mobile)	Air traffic control Aircraft emergency frequency Airband Common traffic advisory frequency Mandatory frequency airport MULTICOM Single Frequency Approach UNICOM
Land-based commercial and government mobile	Base station Business band Mobile radio Professional mobile radio Radio repeater Specialized Mobile Radio Trunked radio system Walkie-talkie
Marine (shipboard)	2182 kHz 500 kHz Coast radio station Marine VHF radio Maritime mobile amateur radio
Signaling / Selective calling	CTCSS D-STAR Dual-tone multi-frequency MDC-1200 Push-to-talk Quik-Call I Quik-Call II Selcall SELCAL
System elements and principles	Antenna APRS Automatic vehicle location Call sign CAD DC remote Dispatch Dynamic range compression Fade margin Link budget Rayleigh fading Tone remote Radiotelephony procedure Voting (diversity combining)

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