Even in my analog EME days, a pretty good test of a CW op, I never once heard a
signal that was there before I started listening. (G4WJS was responding to my
concern about K3's timing issues on FT8 delaying transmission.)
Now the JT65 guys "copy" callsigns by looking up the closest sounding one in a
database with the program saying "Ah ha" that must be the one.
I realize that contest software does the same guessing these days, but I don't
regularly operate in contests, so I use my regular log and type it in myself.
Regards,
Wes N7WS
On 7/3/2018 4:48 PM, Joe Subich, W4TV wrote:
On 2018-07-03 5:16 PM, Wes Stewart wrote:
Hence, I dubbed the mode, "Imaginary" since it hears things that
aren't there.
Not true. It takes advantage of large polynomial encoding that allows
the decoder to "get the message" in spite of missing or damaged bits.
That's no different than *an experienced CW operator* will "copy"
callsigns through noise and QRM by picking up one or two characters
at a time from multiple repeats.
73,
... Joe, W4TV
On 2018-07-03 5:16 PM, Wes Stewart wrote:
In a message to this group back in February I wrote:
Quoting G4WJS: "For FT8 the net effect is that
up to about 5 seconds of a message may be missing yet still
be decoded. The amount missing can be either a truncation or
parts of the message below the decoding threshold. The FT8
message is structured with sync symbols at the start, middle
and end so missing the start or end may have less impact
than missing other parts since mostly sync symbols may be
lost and they contain no message information."
Hence, I dubbed the mode, "Imaginary" since it hears things that aren't there.
Wes N7WS
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