Alla som tänker köra N5J Jarvis Island digitalt behöver ladda ner WSJT-X version 2.7.0-rc6
för att kunna köra FT8 i superfox mode.
Så här skriver Joe Taylor K1JT om tankarna bakom den nya utgåvan och Superfox mode.
The basic SuperFox scheme has been proven to work well.
It delivers the promised weak-signal gain of around 10 dB over multi-streaming FT8 with 5 streams.
The present scheme will certainly be used for the Jarvis Island operations next month, but a variety of things could change after that.
Our goals for design of a SuperFox mode have included the following:
1. Constant envelope waveform, and hence up to 10 dB signal-strength improvement over multi-streamed FT8.
2. Anti-piracy feature: a way to establish legitimacy of signal origin.
3. A way to prevent (or make much more difficult) misuse or our technology by derivative or modified programs, for example enabling robotic strings of QSOs.
4. Better use of available bandwidth: Fox should use (say) at least half of a ~3 kHz slice.
5. Better immunity to QRM, including deliberate QRM.
6. Operational aids for the Fox operator, including longer free text messages.
As you can see, technical details have been important in our planning but sociological, moral, and even legal issues are involved as well.
Objective 2 in the above list involves cyber security matters, an area in which we have little expertise.
Our weak-signal performance requirements demand small message payloads, and these are incompatible with (for example) most public/private key schemes.
For nearly all of its 24 year history the WSJT project has been entirely open source.
Ideally we’d like to keep it that way.
But objective 3 in the list is especially difficult (and likely impossible) to achieve in a fully open source project.
We hope many will work a new one when N5J operates as SuperFox from Jarvis Island. We’ll continue working toward a maxmially effective SuperFox design in the presence of many challenges, including possible software licensing issues, and we welcome allconstructive input from other interested hams.
As always, our efforts are intended to benefit the wonderful hobby we share.
Räven låter så här.
