After reading a little about the new digital radioamateur system WSPR, I found it mus be an amazing thing. Few experiments confirmed, that it is very amazing thing. Many thanks for the author and the team.
The center of the WSPR communication is http://wsprnet.org/. HAM radio operators should register here using their official callsign. Be patient, the process could take few days, which is not any bad. All requests simply needs to be assessed and confirmed individually by the website administrators. After registration, you can contribute to the forum or set your software to report your received radio relations to the database. Also, you can read the forum or the database without registration. View of the database is wonderful. You can filter last N radio relations by Band, Mode, Callsign of the TX station, Callsign of the RX (reporting) station. It is also possible to restrict time period of receive or sort the results by any of the parameter. On the website, there are also links to few other websites, which make statistics or maps from the database records.
Also visit the website of Joe Taylor, a father of the WSPR system https://physics.princeton.edu/pulsar/k1jt/wspr.html, where you can find a technical description, useful links and PC software needed for receive, decode and report radio relations.
At our QTH i set up a simple WSPR receiving station using old computer and two SDR radios from Winradio, WR-G305e for VHF and WR-G313e for shortwave. The VHF antenna is Winradio Discone antenna, which is temporary, not good solution for the first tests. For shortwave, a long wire antenna, approx. 25 m long is used. It is tied between two faculty buildings. Detailed info about the setup will be described later.
The WSPR uses very powerful convolutional code, effective modulation together with a accurate frequency and clock to transmit messages over the world. Messages are short and modulation rate is very low (approx. 1.4648 baud, 2 bits are transmitted in one symbol). For transmision, low power is used from tens miliwatts to few watts. On the receive side, very low SNR signals (down to -34 dB in 2.5 kHz band) are receiverd successfully. It reminds old classics in shortwave amateur radio communication, but the power used is 100 - 1000 times lower. The distance bridged with this radio communication is, as on other shortwave contacts range of hundreds to thousands km.
The main advantage is in the automatic reporting and in the global database of radio relations. Thanks to that, many stations can report any radio transmissions over the world and radio signal propagation can be easily analyzed and visualized. For operators, it is very helpful, that they don't need to sit at their radios permanently, which could be harmful to their health :-) Human's body needs to move and we have too much work, where we must sit.
After few days of WSPR reception on the 40 m shortwave band, there were lot of long distance relations captured. Every hour, approx. 3 messages are received, mean distance is approx. 2000 km (most of Europe, Russia, Great Britain, ...) In time of good propagation (morning, evening) there are signels form USA, East America, India, some ships in Pacific, or Antarctida (is it possible?),...
