digplanet beta 1: Athena
Share digplanet:


Applied sciences






















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[edit]

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[edit]

  • Standard message: callsign + 4-digit locator + dBm (e.g., K1ABC FN20 37)
  • 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.
  • Standard message components after lossless compression: 28 bits for callsign, 15 for locator, 7 for power level, 50 bits total.
  • 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.[2]
  • Keying rate: 12000/8192 = 1.4648 baud.
  • Modulation: continuous phase 4-FSK, tone separation 1.4648 Hz.
  • Occupied bandwidth: about 6Hz
  • Synchronization: 162-bit pseudo-random sync vector.
  • Data structure: each channel symbol conveys one sync bit (LSB) and one data bit (MSB).
  • Duration of transmission: 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: around –28 dB on the WSJT scale (2500Hz reference bandwidth).


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]

Density distribution of WSPR spots, January 2014 vs July 2014, using only most distant reception per spot.


WSPR was originally released in 2008.


  1. ^ http://physics.princeton.edu/pulsar/K1JT/devel.html
  2. ^ a b c d 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 https://gerolfziegenhain.wordpress.com/2013/04/13/raspi-as-wspr-transmitter/
  6. ^ WSPR on Raspi Source Code https://github.com/JamesP6000/WsprryPi

External links[edit]

Original courtesy of Wikipedia: http://en.wikipedia.org/wiki/WSPR_(amateur_radio_software) — Please support Wikipedia.
This page uses Creative Commons Licensed content from Wikipedia. A portion of the proceeds from advertising on Digplanet goes to supporting Wikipedia.
1485 videos foundNext > 

Amateur Radio WSPR 'whisper' software

A video about a software tool for radio amateurs called WSPR or Weak Signal Propagation Reporter which is commonly referred to as 'whisper'.

How To Find HAM Radio Software In Linux Mint and Ubuntu

This video is going to show you how to find and get Amateur "HAM" Radio software for Linux Mint and/or Ubuntu. A lot of the software exists for Windows as well ...

WSPR Ultimate 3 kit for Ham Radio

I've recently built the Ultimate 3 kit available from Hans Summers, here is a very quick tour of the unit and a quick insight into how it performs.

G0SEC Ham Radio Log software

Excellent Ham log software which I myself use, Highly recommend it, looks great and performs well, has some great features.

Netlogger - Ham Radio Internet Logging Software, Part 1

NetLogger is a logging program that can use the internet to transmit check-in information to other users of NetLogger. Net participants that are 'monitoring' the ...

Earth Moon Earth (EME) Amateur Radio Conference 2012 Interviews: K1JT

An informal interview with Dr. Joseph (Joe) Taylor, K1JT, creator of WSJT, MAP65 and WSPR weak signal communication software, by Martin Cadirola, NV3V.

WSPR amateur radio ditial mode

This is a mode for reporting band conditions. Check wsprnet.org for details.

Getting Started on WSPR!

In this video I show how to get started using the WSPR 2.0 software with your HF transceiver. WSPR activity map available at http://WSPRnet.org WSPR 2.0 ...

Amateur radio: Getting Going On VHF #3: Psst, WSPR.

After hours of not having much sucess, lets try a weak signal mode, WSPR (pronounced whisper). WSPR project site: ...

Antenna Testing Using WSPR

I'll show you how to use WSPR software to check to see if my antenna is working. WSPR sends your call sign, power level and grid square during a nearly two ...

1485 videos foundNext > 

We're sorry, but there's no news about "WSPR (amateur radio software)" right now.


Oops, we seem to be having trouble contacting Twitter

Support Wikipedia

A portion of the proceeds from advertising on Digplanet goes to supporting Wikipedia. Please add your support for Wikipedia!

Searchlight Group

Digplanet also receives support from Searchlight Group. Visit Searchlight