JT65 / FSK441 / JT6M

WSJT ("Weak Signal Communication, by K1JT") offers specific digital protocols optimized for meteor scatter, ionospheric scatter, and EME (moonbounce) at VHF/UHF, as well as HF skywave propagation.  The program can decode fraction-of-a-second signals reflected from ionized meteor trails and steady signals 10 dB below the audible threshold. 

The WSJT software package (incorporating FSK441, JT6M, JT65 and JT2/JT4/WSPR experimental modes) can be downloaded from Joe Taylor K1JT's website.

December 2001 QST Article on WSJT by Joe Taylor K1JT

Meteorscatter Documentation:
Art of Copying MS Pings
The use of WJST (FSK441) in 144 MHz band
A Typical Meteor Scatter QSO Experience
Seven Necessary Steps

EME Documentation
Digital EME Communication

All the WSJT modes work on specific timed cycles, and as such it is critical that the PC's time is synchronised very accurately (to within less than a second). You can not successfully have a WSJT QSO without a close synchronization of your local computer's time value to UTC. Period. End of discussion. If you have internet access there is NO EXCUSE for not having a properly synchronized clock.The most popular solution for accurate time calibration is Thinking Man Software's Dimension 4. This is free software, and can be configured to calibrate your PC to an Atomic Time Server at regular intervals.
If you do not have internet access your only option is to try to maintain a manual sync by some broadcast time service. If you can get (and maintain) accuracy within +/- 1 second of UTC you should be able to work other stations. The closer to perfect the better.
Also. Do not assume your PC's clock is stable. Many have highly inaccurate clocks that gain/lose time at a substantial rate.