WSJT-X 2.5.0 now available

The WSJT-X development team has announced the General Availability (GA) release of version 2.5.0.

WSJT-X 2.5.0 introduces an enhanced Q65 decoder that measures and compensates for linear frequency drifts of Q65 signals. Activate this feature by setting a spinner control Max Drift on the WSJT-X main window to a number greater than 0. We suggest a setting of 10 for submode Q65-60A, the recommended submode for EME on 50 and 144 MHz, which will accommodate drift rates up to 20 Hz/minute. Similarly, we suggest Max Drift = 40 for submode Q65-15C, used for for 10 GHz QSOs (up to 900 km) via aircraft scatter and drift rates up to about 20 Hz/s.

WSJT-X Version 2.5 offers eleven different protocols or modes: FST4, FT4, FT8, JT4, JT9, JT65, Q65, MSK144, WSPR, FST4W, and Echo. The first seven are designed for making reliable QSOs under weak-signal conditions. They use nearly identical message structure and source encoding. JT65 was designed for EME (“moonbounce”) on VHF and higher bands and is mostly used for that purpose today. Q65 is particularly effective for tropospheric scatter, rain scatter, ionospheric scatter, TEP, and EME on VHF and higher bands, as well as other types of fast-fading signals. JT9 was designed for the HF and lower bands. Its submode JT9A is 1 dB more sensitive than JT65 while using less than 10% of the bandwidth. JT4 offers a wide variety of tone spacings and has proven highly effective for EME on microwave bands up to 24 GHz. The “slow” modes use timed sequences of alternating transmission and reception. JT4, JT9, and JT65 use one-minute sequences, so a minimal QSO takes four to six minutes — two or three transmissions by each station, one sending in odd UTC minutes and the other even. FT8 is four times faster (15-second T/R sequences) and less sensitive by a few dB. FT4 is faster still (7.5 s T/R sequences) and especially well-suited for radio contesting. FST4 is designed especially for the LF and MF bands. Both FST4 and Q65 offer a wide variety of timed sequence lengths, and Q65 a range of tone spacings for different propagation conditions. On the HF bands, world-wide QSOs are possible with any of these modes using power levels of a few watts (or even milliwatts) and compromise antennas. On VHF bands and higher, QSOs are possible (by EME, scatter, and other propagation types) at signal levels 10 to 15 dB below those required for CW.

The latest release of WSJT-X can be downloaded here.