Last Revision: 25 November 2010
In March 2008 Joe Taylor, K1JT, released a new piece of software called WSPR (Weak Signal Propagation Reporter). Its digital mode is called MEPT_JT (Manned Experimental Propagation Tests, by K1JT)
I am running WSPR since more than 2 years now and it is still very fascinating. Activity has increased somewhat. I am still active on 40m.
The radio I am using now is the Flex-1500 SDR with about output power reduced to 2 watts or the SDR-IQ for receive only.
Here are a few new screenshots which show what is possible with a small antenna (still the dipole) and 2w.
Stations in Central Europe heard by DF9CY or hearing DF9CY
DF9CY WSPR worldwide
You will get WSPR at K1JT's site
More information and databases are at WSPRnet.org
MEPT_JT uses a 4 tone FSK modulation with strong FEC (Forward Error Correction). The tones are separated by 1.46 Hz.
Bandwidth used is ca 6 Hz and the transmission time is 110.6 sec. The length of a single tone is 0,6827 s and maximum allowed drift is about 1 Hz. (It seems some higher drift is still OK ??)