For Contesting will FT8 give way to a new contest mode (FT4)?

Just as FT8 is an evolutionary mode considering the large amount of experience from JT9 and JT65, it looks that FT8 (for the purposes for of contesting) may be displaced a new mode.

Joe (K1JT), Steve (K9AN), and Bill (G4WJS) are moving their latest development to a larger group of testers, aiming for widespread testing by the end of April.

Though bits of information have come my way from a couple sources, I do not think the development team was making a general public announcement, so I’m going to apologize for a teaser post until they give a green light for wider PR efforts.

I am quite grateful that the FT8 continues to advance digital mode amateur radio with efforts on many fronts.

Check in at for any announcements.

— Update — just learned that the FT4 mode was made at least semi-public in recent presentations, and the mode is intended to challenge the QSO rate of RTTY contesting.

—- Update I added more in eth comments, but the pdf the development team released has a lot of information with the proposed test mock-contests!



3 thoughts on “For Contesting will FT8 give way to a new contest mode (FT4)?

  1. k9zw says:


    Joe Taylor, K1JT, Steve Franke, K9AN, and Bill Somerville, G4WJS
    April 22, 2019


    FT4 is an experimental digital mode designed specifically for radio contesting.
    Like FT8, it uses fixed-length transmissions, structured messages with formats optimized for minimal QSOs, and strong forward error correction.
    T/R sequences are 6 seconds long, so FT4 is 2.5 × faster than FT8 and about the same speed as RTTY for radio contesting.
    FT4 can work with signals 10 dB weaker than needed for RTTY, while using much less bandwidth.

    Basic parameters:

    FT4 message formats are the same as those in FT8 and encoded with the same (174,91) low-density parity check code.
    Transmissions last for 4.48 s, compared to 12.64 s for FT8.
    Modulation uses 4-tone frequency-shift keying at approximately 23.4 baud, with tones separated by the baud rate.
    The occupied bandwidth (that containing 99% of transmitted power) is 90 Hz.
    Threshold sensitivity for 50% decoding probability is S/N = –16.4 dB, measured in the standard 2500 Hz reference noise bandwidth.
    A priori (AP) decoding can push threshold sensitivity down to –18 dB or better.

    Much more at their write up



  2. k9zw says:

    From the FRS Community:

    Date: 4/22/19 11:34 AM
    Received: 4/22/19 11:37 AM -0400
    From: (Joe Taylor)
    To: (WSJT software development)

    To: WSJT-X users interested in testing FT4
    From: K1JT, K9AN, and G4WJS

    Soon after the “FT8 Roundup” held on December 1-2, 2018, we
    started serious work on a faster, more contest-friendly digital
    mode that can compete with RTTY-contesting QSO rates while
    preserving many of the benefits of FT8. The result is FT4 — a
    new digital mode specifically designed for radio contesting.

    Over the past month a small group of volunteers have been
    conducting on-the-air tests of FT4. The early tests were very
    successful and helped us to make a number of important design
    decisions. We believe FT4 has considerable promise for its
    intended purpose.

    We’ll soon be ready for testing by a larger group. If you might
    be interested in participating and offering your considered
    feedback, please read the descriptive document “The FT4 Protocol
    for Digital Contesting”, posted here:

    Click to access FT4_Protocol.pdf

    We plan to post downloadable installation packages for WSJT-X
    2.1.0-rc5 on April 29, one week from today. The document linked
    above includes

    – Instructions for installing WSJT-X 2.1.0-rc5 and FT4 configuration

    – Operating instructions for FT4

    – Basic description of the FT4 protocol, modulation, and waveform

    – Detailed sensitivity measurements for FT4 under a wide
    variety of
    simulated propagation conditions

    – Schedule for upcoming test sessions

    Please consider helping us to make FT4 a successful mode for
    digital contesting

    With best wishes and 73,

    — Joe (K1JT), Steve (K9AN), and Bill (G4WJS)



  3. k9zw says:

    Special Note: If you download and participate in this FT4 test cycle keep the WSJT-X software you have been using intact!

    The test cycle software will “Time Out” (Read: Expire) on June 7th.

    The scheduled full release (General Availability) of WSJT-X that will include FT4 as a regular feature is schedule for July 15

    It isn’t assured that the non-FT4 portions of the test version (Release Candidate) are going to be operational after June 7th, so play it safe!



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