[SADXA] Proposal for new MFSK submode

[Wes]

I forget where I heard about this before, probably in the Q&A after Ned's QSO 
Today presentation.  IIRC the "benefits" require even longer sequence times than 
FT8.  I'm already nodding off with FT8 so I can't imagine even longer times.

Wes N7WS


On 8/16/2020 2:08 PM, Jim W wrote:
> The software developers are working on a new digital mode.  Here is some 
> information about it that's been distributed today via another user group to 
> which I belong.
>
> 73, Jim  W9FI
>
>
> -------- Forwarded Message --------
>
> The following is courtesy of Rick K1MU:
>
> Version 2.3 of WSJT-X introduces a new family of digital modes we designate 
> FST41 . These modes have a wide range of capabilities and potential 
> applications. Their fundamental sensitivities are better than most older modes 
> in WSJT-X and are close to the theoretical limits for the same information 
> throughput rates. Particular target applications include▪ WSPR-like, 
> quasi-beacon transmissions on LF and MF bands ▪ QSOs with very weak signals on 
> the LF and MF bands ▪ EME on VHF and UHF bands with T/R sequences both shorter 
> and longer than 60 s ... but other uses will surely be found, as well. We 
> expect that FST4 will serve some of its intended purposes better than older 
> modes in WSJT-X, and without the strict time- and frequency-locking 
> requirements of modes such as EbNaut.
>
> FST4 uses 4-GFSK modulation and offers T/R sequence lengths of 15, 30, 60, 
> 120, 300, 900, and 1800 s. Submodes A, B, C, and D provide different tone 
> spacings, to allow for use with a variety of propagation types and Doppler 
> spreads. Forward error correction uses a low density parity check (LDPC) code 
> with 240 information and parity bits. Transmissions consist of a sequence of 
> 120 information-carrying symbols (2 bits each) interspersed with 40 
> synchronizing symbols. The underlying message payloads contain either 77 bits 
> (the standard payload for FT4, FT8, and MSK144) or 50 bits (the standard for 
> quasi-beacon, WSPR-style messages). With WSPR-like messages the mode 
> designation becomes FST4W and the A submode is always used. In all cases, 
> message formats displayed to the user are the same as in the other 50-bit and 
> 77-bit modes in WSJT-X
>
>
>       73,
>
>  Dave, AA6YQ