[Elecraft] FT8: "Magic radio"?

[Wes Stewart]

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