[Elecraft] [K3] Filters for mixed JT65 and JT9 HF

[Bob]

"I wonder if someone who has significant WSJT-X experience would like to
pontificate of the real benefit of squeezing out another KHz of bandwidth
out?"

Certainly no expert here, but the slightly wider bandwidth does allow a
WSJT-X user to copy the full suggested sub-bands for both JT65 and JT9 at
the same time.  While, to your point, that might not be the wisest thing to
do on 20 meters during a contest when folks tend to ignore the "suggested"
band plans, many times on the WARC bands there are no strong signals to
worry about.

So the bottom line is when it is appropriate, you can use it, and when it
isn't you can always shift to a more narrow roofing filter and focus on one
mode vs the other.  It's simply an option.

The ability of JT65 and JT9 to decode signals below the noise level is the
closest thing to magic that I've come across in my ham experience, allowing
extremely low power communication to be accomplished with sub-optimal
antennas.  I can work Australia, half way around the world, regularly with
0.5 watts of output  But it isn't magic, just applied mathematics.  And
there is no denying there is something almost magical about decoding a
signal that you can't even hear.

73, Bob, WB4SON