ZS2EZ FT8 HF OPERATIONS

INTRODUCTION

On 11 July 2017 the WSJT Development Group announced the Beta Release of WSJT-X Version 1.8.0 (RC1). Included in this release was a new mode : FT8

From the release notes:

Brief Description of the FT8 Protocol
		-------------------------------------

WSJT-X Version 1.8.0 includes a new mode called FT8, developed by K9AN
and K1JT.  The mode name "FT8" stands for "Franke and Taylor, 8-FSK
modulation".  FT8 uses 15-second T/R sequences and provides 50% or
better decoding probability down to -20 dB on an AWGN channel.  An
auto-sequencing facility includes an option to respond automatically
to the first decoded reply to your CQ.  FT8 QSOs are 4 times faster
than those made with JT65 or JT9.  FT8 is an excellent mode for HF
DXing and for situations like multi-hop E_s on 6 meters, where deep
QSB may make fast and reliable completion of QSOs desirable.

Some important characteristics of FT8:

  - T/R sequence length: 15 s
  - Message length: 75 bits + 12-bit CRC
  - FEC code: LDPC(174,87)
  - Modulation: 8-FSK, tone spacing 6.25 Hz
  - Constant-envelope waveform
  - Occupied bandwidth: 50 Hz
  - Synchronization: 7x7 Costas arrays at start, middle, and end
  - Transmission duration: 79*1920/12000 = 12.64 s
  - Decoding threshold: -20 dB; several dB lower with AP decoding
  - Multi-decoder finds and decodes all FT8 signals in passband
  - Optional auto-sequencing and auto-reply to a CQ response
  - Operational behavior similar to JT9, JT65

We plan to implement signal subtraction, two-pass decoding, and use of
a priori (AP) information in the decoder.  These features are not yet
activated in v1.8.0.

We haven't yet finalized what the three extra bits in the message
payload will be used for.  Suggestions are welcome!

	-- Joe, K1JT, for the WSJT Development Team

The 3rd and final Release Candidate was posted on 16 October 2017, and the final WSJT-X 1.8.0 GA release was made available on 27 October 2017. The current GA Release is 2.2.2, and there are 2.3.0 "RC" Releases currently available. The full release notes and the full installer package can be found HERE. This page includes installers for MacOS X and various Linux Distros.

FT8 has significantly changed the Digital landscape - HF Digital will never be the same again!

SOME CONSIDERATIONS FOR USING FT8 ON HF:
The most CRITICAL aspect of FT8 operation is EXACT time calibration. Due to the short 15 second periods being any more than 1 second out can result in other stations being unable to decode your signal. ACCURATE time-synchronisation software such as Meinberg NTP (recommended) or Dimension 4 are a necessity.  Avoid ALC action if possible - much like any other audio input to an SSB transmitter FT8 can generate a poor signal if over driven. FT8 is a weak signal mode, NOT a low power mode. Its primary design purpose is to facilitate Sporadic E communications on VHF. For use on HF there is no issue with using as much power as is needed to establish a contact with a DX station, PROVIDED YOU DO NOT OVERDRIVE YOUR AUDIO!

MY ACTIVITY
ZS2EZ has been active in FT8 on the HF bands since it's release in the WSJTX-1.8.0-RC1 package on 11 July 2017. My first QSO in this mode was with YT1XN on 20m on 13 July 2017. [Before starting operations I had to make some changes to my logging program to accept the new mode]. Within a VERY short time I had in excess of 100 QSOs logged, and found the rapid pace of the mode very well suited to my operating style.  Due to poor propagation towards NA it took a while to log my first few American stations, but have now completed my WAS on FT8 (with confirmations via LoTW) when logging WC0G in ND on 30m (13/10/2017). By end December 2017 I have also logged in excess of 2 500 QSOs with more than 150 DXCC entities. By the end of 2020 I had reached over 20 000 QSOs logged, and 242 entities worked!

I will gladly respond to sked requests for any band in FT8!!

Below is my table of US States worked and needed in my quest for WAS via FT8!

WAS on FT8 : My contacts table: (all confirmed via LoTW)