Re: [CQ-Contest] Contesting and the FT8 Revolution

[David Gilbert <ab7echo@gmail.com>]

I've gone through this stuff in detail with someone who knows far more 
about digital signal processing than either of us, and everything I said 
is possible with the exception that I will acknowledge that synchronous 
operation has advantages.  My postulation does NOT involve adhering to 
the FT8 or FT4 protocol as you seem to suggest below.  I proposed a mode 
similar to FT4 except wider bandwidth (which dose NOT necessarily 
degrade S/N as you claim) and a different set of other parameters ... 
plus conversion to CW instead of fixed text blocks simply to make it 
more adaptable to common contesting practice.
I don't care what you say ... it can be done, but it's going to take 
somebody to work it up from scratch instead of trying to port FT8 or FT4 
to a different user interface.  Just about everything you said below is 
wrong simply because you're stuck in that mental trap.
I will say again since nobody seems to get it ... FT8 and FT4 as 
implemented by WSJT-X are not some new invention that locks all other 
similar efforts into the same set of boundary conditions that K1JT 
chose.  K1JT made very clever use of modern signal processing to create 
FT8, FT4, and other similar modes but he chose a VERY restrictive set of 
boundary conditions in order to implement his own particular vision.  
Those same modern signal processing techniques could be implemented with 
different boundary conditions to give ham radio (and in particular 
contesting) a much cleaner and more usable interface.  Go read K1JT's 
descriptions of what he did and what techniques he used, and if you then 
do a bit of searching you will find lots of technical discussions of 
those same methods applied in different ways to other tasks.  WSJT-X is 
unique, but the the science behind it is not.
I know that I am flogging a dead horse here, but it frustrates the hell 
out of me to see the opportunity that is being squandered simply because 
the guy that came up with the first popular manifestation of modern 
signal processing had such a limited vision of what it should be.
Dave   AB7E



On 7/2/2021 10:39 AM, Bill Coleman wrote:
> > On Jun 21, 2021, at 2:59 PM, David Gilbert <ab7echo@gmail.com> wrote:
> >
> > Everything you just said there is the fault of WSJT-X as a user interface ... 
> > not FT8 or FT4 as a mode.  They are NOT the same thing.  WSJT-X is simply the 
> > narrow and restrictive vehicle by which we have been exposed to the exceptional 
> > weak signal capability of modern digital processing (forward error correcting, 
> > Costas array processing, etc).  We'd all be having a LOT more fun with a more 
> > open ended interface ... possibly with these parameters:
> >
> > 1.  wider individual signal bandwidth, such as maybe 200 Hz instead of 83 Hz.
> A wider bandwidth would potentially decrease the sensitivity of the mod
>
> > 2.  fully tunable over the typical digital sub band (like RTTY does)
> There’s absolutely nothing stopping you from running FT8 or FT4 anywhere in the 
> digital sub-bands. You may not have many QSOs there, but it is possible.
>
> > 3.  Asynchronous in time ... i.e., not locked to a discrete and specific clock 
> > window
> This requirement is fundamentally incompatible to the way that FT8 or FT4 work. 
> The fixed transmission / reception windows are clearly a part of the mode.
>
> > 4.  shorter blocks of data with continuous feed of the blocks
> Shorter blocks? The blocks today only convey 77 bits (BITS!) of information. 
> That’s right, it takes nominally 15 (or 7.5) seconds to transmit 77 bits 
> (BITS!) of information.
>
> And continuous blocks don’t work either.
>
> > 5.  sent via text blocks on the transmit end ... exactly as DVRs and contest 
> > loggers do now
> Remember the 77 bits (BITS!) mentioned earlier? Each transmitted block has a certain 
> structure, and typically contains the two callsigns (caller and callee) and a little bit of 
> additional text. There’s no much room for sending any random text, because 
> there’s only a few bits available to on each sent block.
>
> > 6.  displayed as text or converted to audible CW (or even digital voice) on the 
> > receive end
> Bill Coleman, AA4LR, PP-ASEL        Mail: aa4lr@arrl.net
> Web: http://boringhamradiopart.blogspot.com
> Quote: "Not within a thousand years will man ever fly!"
>              -- Wilbur Wright, 1901
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