Weak Signal Propagation Reporter
Weak Signal Propagation Reporter ( WSPR , English pronunciation of whisper for "whisper") is the name of an automatic data transmission process that enables secure transmission even when the transmission channel is very disturbed (e.g. very weak useful signal disturbed by thermal noise ). It is mainly used in the amateur radio service , but also partly commercially.
use
Shortwave signals can often be transmitted worldwide because the upper layers of the ionosphere are reflective for frequencies below about 9 MHz at any angle of incidence. The usable frequency can increase to around 50 MHz with a shallower radiation angle and suitable solar activity, but it is hardly predictable. For this reason, the reception quality of distant beacon transmitters is recorded to continuously determine the propagation conditions on shortwave . In addition to the beacons that have been used for a long time and send in Morse code, there are other systems. WSPR is a particularly good method for studying propagation conditions, but its narrow bandwidth makes it prone to Doppler shift . The signals from these low-power beacons can be up to 32 dB below the interfering signals (i.e. the power of the useful signal is more than 1000 times less than that of the interfering signals, based on an AF bandwidth of 2500 Hz), which is why the signals are only received using special, narrow-band reception methods can decode.
description
This technique was developed in 2008 by radio amateur and Nobel laureate in physics Professor Joseph Hooton Taylor, Jr. (K1JT) as part of the WSJT protocol group. The signals are transmitted and received via a transceiver for single sideband modulation connected to the sound card. The WSPR method uses frequency shift keying with four symbol frequencies (4-FSK) and a forward error correction . The clocks of the transmitter and receiver must be precisely synchronized to within a few seconds. The transmissions take place at intervals of 2 minutes each beginning with even-numbered minutes (e.g. from xx: 04 am to xx: 06 am, etc.)
The WSPR signal has a very narrow bandwidth (5.9 Hz ). It therefore only requires 0.1% of the bandwidth of an AM broadcast signal. In the reception bandwidth of just 200 Hz supported by the WSPR software, several signals can be received and decoded at the same time.
WSPR is enjoying increasing popularity in the amateur radio service worldwide for beacon transmissions, especially on shortwave on the amateur radio bands from 160 - 6 meters and on the long-wave frequencies of the 630-meter and 2.2-kilometer bands that can be used by radio amateurs . Terrestrial range checks in the VHF / UHF range ( 144 / 430 MHz ) are carried out.
software
WSPR
| Weak Signal Propagation Reporter | |
|---|---|
| Basic data
|
|
| Maintainer | Joseph Hooton Taylor, Jr. (K1JT) |
| developer | Joseph Hooton Taylor Jr. |
| Publishing year | 2008 |
| Current version | 2.0 r1714 |
| Current preliminary version | 2.12 r3617 |
| operating system | Windows , Linux , macOS |
| category | Amateur radio software, communication protocol |
| License | GNU General Public License |
| http://physics.princeton.edu/pulsar/K1JT/wspr.html | |
With the presentation of the process, Taylor also made a corresponding software WSPR available for PCs with sound cards as free software under the GNU General Public License . The software supports automatic uploading of decoded WSPR signals to the WSPRnet.org website , which is accessible to everyone. The information received is saved and evaluated there. For example, transmission and reception locations are shown on a world map, which is not the case with classic propagation beacons .
WSPR Version 2.0 has been available since November 2009. Version 2.0 of WSPR includes an extension of the software for controlling common amateur radio devices via the CAT interface (serial or USB emulated interface for controlling the radio devices). Furthermore, the WSPR protocol was modified in order to now also transmit callsigns with a prefix, for example DL / and suffix extensions / p, and also full QTH locators (location IDs). The website WSPRnet.org with the database integrated there supports all extensions of version 2.0 of WSPR.
WSPR-X
| WSPR-X | |
|---|---|
| Basic data
|
|
| Maintainer | Joseph Hooton Taylor, Jr. (K1JT) |
| developer | Joseph Hooton Taylor Jr. |
| Publishing year | 2013 |
| Current version | 0.8 r3058 |
| operating system | Windows , Linux macOS |
| category | Amateur radio software, communication protocol |
| License | GNU General Public License |
| http://physics.princeton.edu/pulsar/K1JT/wspr.html | |
A new software version, WSPR-X, has existed since January 2013, which, in addition to the previous 2-minute mode, enables beacons to be transmitted every 15 minutes. (e.g. from xx: 00 am to xx: 15 pm, etc.) Compared to the 2-minute mode, a 9 dB higher sensitivity is achieved. The main purpose of this new mode is to facilitate WSPR operation on long and medium wave , since the pitch of only 0.183 Hz is smaller than the Doppler shift that typically occurs on short wave.
WSJT-X
| WSJT-X | |
|---|---|
| Basic data
|
|
| Maintainer | Joseph Hooton Taylor, Jr. (K1JT) |
| developer | Joseph Hooton Taylor Jr. |
| Publishing year | 2001 |
| Current version | 1.7.0 (December 2016) |
| operating system | Windows , Linux , FreeBSD , OSX |
| category | Amateur radio software, communication protocol |
| License | Open source |
| http://physics.princeton.edu/pulsar/K1JT/wsjtx.html | |
The WSJT-X program implements the new WSJT operating modes JT4, JT9, JT65, QRA64 and ISCAT as well as MSK144 and WSPR. WSJT-X thus covers all operating modes developed by K1JT for long, medium, short, ultra-short and centimeter waves , including the JT65 and QRA64 preferred for earth-moon-earth as well as the optimized operating mode JT4. This means that no additional software such as WSPR or WSPR-X is required for WSPR either.
Alternative WSPR reception software for LINUX / Banana Pi
| k9an-wsprd | |
|---|---|
| Basic data
|
|
| Maintainer | Steven Franke (K9AN) |
| developer | Joseph Hooton Taylor Jr. |
| Publishing year | 2008 |
| operating system | Platform independence |
| category | Amateur radio software, communication protocol |
| License | GNU General Public License |
| //github.com/k9an/wsprcan/ | |
In addition to the original software, there is also software from Steven Franke (K9AN) in which the decoder was written in the C programming language . This software also runs on computers with lower performance such as the Raspberry Pi or Banana Pi .
The decoder can be operated with a graphical user interface under the X Window System or via Shell.
hardware
A WSPR station usually consists of a computer and a transceiver. However, it is also possible to build beacons yourself with simple means or to use special beacon transmitter kits such as those from QRP Labs .
A simple direct mixer receiver with a quartz oscillator as an input filter is sufficient for reception .
literature
- Joe Taylor, K1JT and Bruce Walker, W1BW: WSPRing around the world . In: QST . November, 2010, ISSN 0033-4812 , p. 30-32 .
- Eike Barthels, DM3ML: Wave Whispering with WSPR . In: radio amateur . No. 3 , 2009, ISSN 0016-2833 , p. 258 .
Web links
- official website (in English)
- Description of the WSPR 2.0 protocol (PDF, English; 731 kB)
- WSPRNet Propagation Map
- WSPRlive dispersion analysis (in English)
Remarks
- ↑ amateur radio call sign , locator large field , transmission power ( dBm )
Individual evidence
- ^ Joseph Hooton Taylor, Jr. (K1JT): Weak Signal Communication Software. In: WSJT Home Page. Retrieved April 14, 2013 .
- ↑ Urs Mansmann: Beyond the noise limit - use of computers in amateur radio in c´t 21/08
- ↑ WSPRnet WSPR Network. Retrieved April 3, 2015 .
- ^ Mark Jessop: A Radio Relay System for Remote Sensors in the Antarctic. (PDF; 4.4 MB) University of Adelaide , October 7, 2010, archived from the original on March 4, 2016 ; accessed on April 3, 2015 .
- ^ Joseph Hooton Taylor, Jr. (K1JT): WSPR-X User's Guide. (PDF; 830 kB) January 16, 2013, accessed on February 18, 2013 (English).
- ^ Joseph Hooton Taylor, Jr .: WSJT-X User Guide. 1. Introduction. December 19, 2016, accessed January 29, 2017 .
- ↑ K9AN in the Federal Communications Commission (FCC) database
- ↑ wspr decoder ported to C, Steve K9AN
- ↑ WSPR RX for LINUX - WSPR receiver with a comfortable user interface
- ↑ WSPR RX with the Banana PI WSPR receiver with the Banana PI as a fully automatic console solution
- ↑ WSPR Beacon with Si570 and Atmel AVR
- ↑ WSPR Beacon with Raspberry Pi
- ^ The Radio Whisperer, George R. Steber, Nuts & Volts Magazine, January 2012