LRS member Brian Howie GM4DIJ is now running a WSPR propagation beacon on 4 metres. He has provided the following information:
WSPR is the Weak Signal Propagation Reporter designed by Nobel Prize Winner Joe Taylor K1JT: Http://physics.princeton.edu/pulsar/K1JT/
WSPR uses very narrow band signal processing techniques to decode weak signals. It has been very popular on the short wave bands for a few years and there are now a few WSPR stations on 6m and 4m.
The software for decoding WSPR signals can be downloaded from the K1JT website above. This is a soundcard decoding program which will run with the same cabling etc as MMTTY, PSK-31 and other soundcard programs.
Example of WSPR display at GM4DIJ when he was receiving G0MJI in Liverpool at 16 dB below the noise level.
Received signals are automatically uploaded to the website of WSPRnet, the WSPR Network: Http://wsprnet.org/drupal/
The website collates the propagation data from all received stations and plots it on a map, so it is possible to see in real time what paths are open.
This is a WSPR 4m propagation map as received at GM4DIJ.
Brian’s WSPR beacon runs 20W on 70.09251 MHz at 20% Tx time and 80% Rx time. The antenna is a 6-element yagi pointing just east of south. The station is currently operational on evenings from about 7pm to 12pm, and afternoons and evenings on some weekend days.
The WSPR signal consists of a short burst of digital data followed by what sounds like a pure carrier but is in fact very narrow FSK at a slow data rate. From the user manual:
• Keying rate: 12000/8192 = 1.4648 baud.
• Modulation: continuous phase 4-FSK, tone separation 1.4648 Hz.
• Occupied bandwidth: about 6 Hz
The GM4DIJ CW ID is set to run every 15mins
Brian reports that while his signal will not be weak locally (599 + 20dB at GM3PSP!) he has been heard in England, Denmark and Holland. He uses the term “heard” loosely as his signal report was 22dB below the noise at G0MJI in Liverpool.