WSPR (amateur radio software)

Weak Signal Propagation Reporter ( WSPR, Eng. Whisper pronunciation for " whisper " ) is the name of an automatic data transfer process, the secure transmission even in heavily degraded transmission channel allows (eg very weak useful signal disturbed by thermal noise ).

Use

Short wave signals can often be transmitted worldwide because the upper layers of the ionosphere for frequencies below about 9 MHz is reflected at any angle of incidence. The usable frequency can rise at a shallower angle radiation and suitable solar activity to about 50 MHz, but is hardly predictable. Therefore, the quality of reception of distant beacon transmitter is recorded to the ongoing investigation of the propagation conditions on shortwave. In addition to the already longer used beacons, which transmit in Morse code, there are other systems. A particularly well suited for the study of propagation method is WSPR, because of the low bandwidth, however, it is prone to Doppler shift. The signals of the low power beacon, up to 32 dB below the interference signals lie (ie the power of the desired signal is more than 1000 times less than that of the noise, based on a low frequency range of 2500 Hz ), and therefore only specific, narrow band reception method, the signals can decode.

Description

This procedure was in 2008 by the radio amateur and Nobel laureate in Physics Professor Joseph Hooton Taylor Jr. ( K1JT ) developed as part of the WSJT suite of protocols. Transmission and reception of the signals is done via a computer connected to the sound card transceiver for single-sideband modulation. The WSPR method uses frequency with four symbol frequencies (4- FSK) and forward error correction. The clocks of the transmitter and receiver must be synchronized to a few seconds exactly. The transmissions take place over intervals of 2 minutes in length, each beginning to even minutes ( eg xx 04 xx clock to 06 clock, etc.)

The WSPR signal has a very low bandwidth ( 5.9 Hz). Thus it requires only about 0.1% of the bandwidth of an AM radio signal. In support of the WSPR software receiving bandwidth of only 200 Hz, multiple signals can be received and decoded simultaneously.

WSPR enjoys the amateur radio service worldwide increasingly popular for beacon transmissions on short wave ( frequency bands from 160 meters up to the 6- meter band ) and on the long wavelength for radio amateurs usable frequencies (wavelength > 600 meters). There are ( 144/430 MHz) performed terrestrial range tests in the VHF / UHF range.

Software

Taylor presented with the idea of the method, a corresponding software WSPR for PC with a sound card as free software under the GNU General Public License. The software supports automatic upload of decoded WSPR signals on the website WSPRnet.org that is accessible to everyone. There, the received information is stored and evaluated. For example, carried the representation of transmit and receive locations on a world map, which is not the case for classical propagation beacons.

Since November 2009 WSPR version 2.0 is available. The version 2.0 of WSPR includes an extension of the software for the control of common amateur radio equipment on the CAT interface ( serial or emulated via USB interface to control the radio equipment). Furthermore, the WSPR protocol was modified to now also transfer with call sign prefix, for example, DL / and Suffixerweiterungen / p and also full QTH Locator (location codes ). The website WSPRnet.org there with the built-in database support all conducted enhancements in version 2.0 of WSPR.

WSPR -X

Since January 2013, a new software version, WSPR -X, which in 15 the beacon transmissions enables addition to the previous 2- minute mode minutes interval exists. (eg xx 00 xx clock to 15 clock, etc.) Compared to the 2- minute mode, a 9 dB higher sensitivity is achieved. The purpose of this new mode is especially facilitating the WSPR operations on long and medium wave, because the tone spacing of only 0.183 Hz is smaller than the Doppler shift, which typically occurs on shortwave.

Applications

Usually a WSPR station from a computer and a transceiver. However, it is also possible with simple means to build beacon itself.