New FT4 Beta Release “Leaps and Bounds” Better than Earlier Iterations

User reports have been favorable in the wake of the release of another new beta version of the FT4 protocol by the WSJT-X Developoment Group this week. WSJT-X 2.1.0-rc7, which is now available for testing, is not compatible with any previous FT4 releases. A short mock contest session to wring out the contesting features of FT4 took place on June 4.

“Thanks to all who participated in yesterday’s FT4 mock-contest practice session — and especially to those who provided useful feedback. It is much appreciated!” said developer Joe Taylor, K1JT. “Everyone likes the 7.5-second T/R sequences, which provide operators with significantly more human interaction time than in previous revisions of FT4. Users also appreciated the sensitivity improvements and a larger range of acceptable time offsets (DT).” DT represents the combined clock difference for the transmitting and receiving computers, he explained.

Based on data compiled by Steve Franke, K9AN, Taylor said that it appears developers have the WSJT-X timing behavior under good control on all supported platforms, and the range of measured signal-to-noise values extended down to –21 dB.

“I operated for about 3 hours using 100 W and a dipole,” Taylor recounted. “I copied transmissions from 263 unique call signs and made 143 QSOs in 29 states, 5 Canadian provinces, and 15 DXCCs.”

Taylor said the developers anticipate addressing all remaining issues they’re aware of. “I believe we are on a good path toward a General Availability (GA) release of WSJT-X 2.1.0 by mid-July,” he said.

“This new version of FT4 is leaps and bounds better than before,” said Mike Black, W9MDB, in a June 4 post to the Yahoo WSJT Meteor Scatter and Weak Signal Group. “I worked almost everybody I could see without any repeats. Seems like we have a winner here.”

Changes, improvements, and bug fixes that have been made since WSJT-X 2.1.0-rc5 include:

T/R sequence length increased from 6.0 to 7.5 seconds.
Signal bandwidth decreased from 90 Hz to 80 Hz.
Improved sensitivity: Threshold S/N is now –17.5 dB.

Release candidate WSJT-X 2.1.0-rc7 will be available for beta-testing through July 21, and it will permanently cease to function after that date. It will not be usable during the ARRL June VHF Contest or during ARRL Field Day. Taylor advised using WSJT-X 2.0.1 and FT8 for these events.

Downloadable installation packages for WSJT-X 2.1.0-rc7 under Windows, Linux, and macOS are available on the WSJT-X web page.