WSPR (amateur radio software)

WSPR
Developer(s) Joe Taylor, K1JT
Initial release 2008
Development status active
Written in Python (GUI), Fortran, C [1]
Operating system Cross-platform
Available in English, Italian, Spanish, French, German, Japanese, Polish, Portuguese, Russian
Type Amateur radio and DSP
License GPL
Website physics.princeton.edu/pulsar/K1JT/wspr.html

WSPR (pronounced "whisper") stands for "Weak Signal Propagation Reporter". It is a computer program used for weak-signal radio communication between amateur radio operators. The program was initially written by Joe Taylor, K1JT, but 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 S/N 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.[2] The WSPR protocol compresses the information in the message into 50 binary digits. These are encoded using a convolutional code with constraint length K=32 and a rate of r=1/2.[2][3] 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.[2]

Protocol specification

Applications

Raspberry Pi as WSPR transmitter

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 Si570.[4] The Raspberry Pi can also be used as WSPR beacon.[5][6]

History

WSPR was originally released in 2008.

References

  1. http://physics.princeton.edu/pulsar/K1JT/devel.html
  2. 2.0 2.1 2.2 2.3 Joe Taylor, K1JT: WSPRing Around the World. QST November (2010), p. 30-32.
  3. G4JNT: The WSPR Coding Process: Non-normative specification of WSPR protocol http://www.g4jnt.com/Coding/WSPR_Coding_Process.pdf
  4. WSPR Beacon with Si570 and Atmel AVR http://wsprnet.org/drupal/sites/wsprnet.org/files/si570wspr.pdf
  5. WSPR Beacon with Raspberry Pi http://g.ziegenhain.com/2013/04/raspi-as-wspr-transmitter
  6. WSPR on Raspi Source Code https://github.com/JamesP6000/WsprryPi

External links