The weak signal performance of FT-8 is in a large part due to its time synchronization,
which is part of the specification of FT-8, not a "limitation" of wsjtx. With
an asychronous digital mode the decoder has to figure out when a transmission starts. For
weak signals that is a very hard problem. The same weak signal performance is NOT
possible without the synchronization.
FT-8 and FT-4 are lousy contest modes because when signals are strong they are
too slow, and they can't adapt to signal strength like CW or SSB can. FT-8 has
majorly impacted VHF contesting. Now many op's 6m radios are stuck on 50.313
FT-8 and many have disconnected microphones. 6m Es is however not always a weak
signal mode, and in a strong opening FT-8 is simply too slow comapred to SSB.
FT-4 is a partial solution but nobody wants to leave 50.313 FT-8.
A better way would be to run FT-8 and FT-4 on the same channel and have wsjtx
decode both at the same time.
Tor N4OGW
On Monday, June 21, 2021, 2:52:27 PM CDT, 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.
2. fully tunable over the typical digital sub band (like RTTY does)
3. Asynchronous in time ... i.e., not locked to a discrete and specific
clock window
4. shorter blocks of data with continuous feed of the blocks
5. sent via text blocks on the transmit end ... exactly as DVRs and
contest loggers do now
6. displayed as text or converted to audible CW (or even digital voice)
on the receive end
Such an interface would be amenable to DXing, contesting, or ragchewing
with a user experience similar to CW or RTTY, except with far better
weak signal performance. It would even be possible to have a built in
CW to text converter on the transmit end for CW ragchewing. In my
opinion, it's almost a crime that the capability of FT8/FT4 is being so
completely constrained by WSJT-X.
The weak signal performance of FT8/4 is entirely possible with a user
interface that would be hard to distinguish between how we typically use
CW and RTTY for DXing and contesting. I've dug into this stuff enough
to know that (and I have a son who has done leading edge work on this
kind of thing for a living for over 20 years) ... I'm just not smart
enough to code it.
73,
Dave AB7E
On 6/20/2021 10:54 PM, Jeff Blaine wrote:
This point that Ted makes - the FUN aspect - is in my opinion why
FT8/FT4 contesting struggles.
Yes, it's fun to make FT8/FT4 contacts initially. And the underlying
technology is about as cool as it possibly gets. But from a
competitive standpoint, once the novelty wears off, it pretty quickly
becomes monotonous because there is no significant operator
intervention possible to push the rate or the mults higher.
A competitive game (which is really the essence of radiosport, under a
different term) which is going to drive increased and sustained
participation must have a method that provides an increased challenge
and a performance-based reward mechanism which is the payback for the
increased skill. Unfortunately in FT8/FT4 the computer (and the
mode's structure) controls virtually all normal contest skill set,
save for picking the right band. I'm generalizing here, but
essentially that's it. One can go from an new FT8/FT4 contester -->
to an experienced one in about an hour or few. And after that, almost
nothing you do with respect to operation will significantly affect
your results. The variables are limited, with perhaps the band chosen
being the most significant pick. Otherwise, it's mostly up to the
computer.
Of course that depends on how the contest is setup. Some formats make
more sense to me than others. I've always thought the grid-square
based mileage method popularized by the RTTY Makrothon and CW/SSB Stew
Perry contests provided a format that was almost ideal for the FT8/FT4
mode. It provides a about as close to an even playing field with
respect to location as you are going to get in radiosport. And it's
fun to watch what grid square pops up with each new caller as that
drives a variable points count.
Unfortunately, even with a complementary contest format like mentioned
above, the operator performance reward is absent once you get the hang
of it, and it's that aspect of the mode that puts an upper limit as to
the "fun" realizable.
73/jeff/ac0c
alpha-charlie-zero-charlie
www.ac0c.com
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