[CQ-Contest] Contesting and the FT8 Revolution
Jeff Clarke
ku8e at ku8e.com
Sat Jul 3 12:36:42 EDT 2021
Again for the umpteenth time... Why are people talking about this
subject on a CONTESTING reflector? Neither FT8 or FT4 are contesting
modes. I guess this is more proof that FT8 has totally taken over ham
radio? I guess people are really bored and can't help themselves? Hello
Mr Moderator can you please tell people to stop!
Jeff
On 7/2/2021 09:01 PM, David Gilbert wrote:
>
> 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 at 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 at arrl.net
>> Web: http://boringhamradiopart.blogspot.com
>> Quote: "Not within a thousand years will man ever fly!"
>> -- Wilbur Wright, 1901
>>
>
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