© Christoph Petermann DF9CY 2010

Last Revision: 25 November 2010

WSPR Weak Signal Propagation Reporter

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.

WSPR with Flex-1500 Radio and 2w

Stations in Central Europe heard by DF9CY or hearing DF9CY

DF9CY WSPR worldwide

Download and Links

You will get WSPR at K1JT's site

More information and databases are at WSPRnet.org

Some technical details

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 ??)