Upcoming Changes To FT8 From Joe Taylor K1JT

Courtesy of the Facebook FT8 group, here is a sneak preview courtesy of Joe Taylor, K1JT. Before reading, those who steadfastly refuse to update your software because of some silly clinging to one feature or another need to take note of the second to last block of text in Joe’s note... now without further ado, here’s the note from Joe:

“Hi to all,

Of course we are well aware of the issues many have experienced when using WSJT modes in North American VHF contests. To summarize, there are two main problem areas:

– Decoding of messages with two callsigns followed by “R ” and a 4-character grid, and the related auto-sequencing, depend of proper and coordinated setting of a checkbox at both stations.

– There is a crying need for transparent support of “/R” (Rover)
callsigns in all standard messages, during contests.

Here’s some background information aimed at relative newcomers and casual users of WSJT, followed by a brief preview of program features we plan to make available in Version 2.0 of WSJT-X.

Contest Mode

Standard JT-style messages (those used in all of the structured WSJT modes) have 71 information bits: two 28-bit callsigns and a 15-bit grid locator. The 15-bit field can alternatively convey a signal report (with optional “R”), or “RRR”, “RR73”, or “73”. One additional bit re-purposes the 71 bits to carry a 13-character free test message. In a 72-bit packet there are NO free bits available to insert “R ” before a
grid locator, or “/R” after a callsign.

The “NA VHF Contest” checkbox presently in WSJT-X is a stop-gap feature added in 2016 to the MSK144 mode, and later to FT8. These modes conventionally use 15-second T/R intervals and offer semi-automated message sequencing. NA VHF contests require the exchange of 4-character
grid locators. Signal reports are OK, but not required. Contesters wanted a way to send messages like “K1ABC W9XYZ R EN37”, thereby increasing their QSO rates by eliminating some transmissions from the standard minimal-QSO sequence.

Rovers move from grid to grid and must append “/R” to their callsign during the contest. These hardworking folks definitely need some help if they are to use WSJT modes effectively.

All structured modes currently supported in WSJT-X permit messages like these:


…. but you can’t use a second callsign in place of the “CQ” or “DE”. Once again, there is no room for such information in a 72-bit packet.

Some time ago we created workarounds that enable QSOs using a “/R” callsign or an “R+grid” message fragment. But these capabilities are limited and necessarily somewhat clumsy. Users must understand what’s possible and what’s not, and they must be careful about some necessary
program settings. Decoding “R+grid” messages requires ticking a checkbox, and if someone else sends you standard signal reports you need to uncheck the box or manually edit your messages. Also, for reasons explained in the WSJT-X User Guide, this feature cannot work well when world-wide propagation is possible — as it has been recently on 6 meters.

All in all, it’s not a happy situation — especially when considering the typical presence of many casual operators who happen upon a contest and just want to make a few QSOs.

Recently K9AN, G4WJS, and I have been developing enhanced versions of the MSK144 and FT8 protocols that extend the message payload to 77 bits. For a taste of what’s to come, here’s a brief list of things made possible by the extra bits:

1. NA VHF Contest operation with full support of grid exchanges and “/R” (Rover) callsigns

2. EU VHF Contest operation with the exchange of 6-digit grids, QSO serial numbers, and “/P” (portable) callsigns

3. ARRL Field Day operation with standard Field Day exchanges

4. ARRL RTTY Roundup operation with standard contest exchanges

5. Better and more user-friendly support for compound and nonstandard callsigns

6. A special “telemetry” message format for exchange of arbitrary information up to 71 bits

7. The existing FT8 DXpedition mode will be supported, and a more powerful DXpedition mode may be offered as well.

All of these features work seamlessly and automatically. No “contest mode” checkboxes are needed. In most situations decoding sensitivity will be slightly better than at present for FT8; for MSK144 it will sometimes be about 0.5 dB worse. Occupied bandwidths will be the same as they are now, and false-decode rates will be significantly lower.

Much of the necessary programming is finished. Many of the new features have been tested on the air, and we find them to work well.

Don’t rush to download something — these capabilities are not yet publicly available. There is more testing and code optimization to do.

With summer vacation plans, etc., our current plans call for a
beta-testing period probably starting in mid to late September. A full release should then be possible a couple of months later.

In particular: we are planning to make WSJT-X Version 2.0 available in time for you to read its new documentation and practice using it before (for example) the ARRL RTTY Roundup, January 5-6, 2019, and the ARRL VHF
Sweepstakes, January 19-21, 2019.

THIS IS IMPORTANT: The new protocols cannot be backward compatible with the existing ones. We will probably provide some temporary “bi-lingual” capability for FT8, but not for MSK144. It will be essential for users to upgrade to Version 2.0 in order to use the new features and communicate with others who have made the upgrade.

We will provide plenty of advance notice about a transition interval and an essential “must upgrade by” date.

— 73, Joe, K1JT

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