A while back on the 1000MP reflector a comment was posted by a ham who
questioned whether a key click mod a la Inrad is needed on later Mark V's.
Taking a cue from that comment, I checked my Mark V, which was manufactured
in February 2002, using my JRC JST-245 transceiver and found the audible
keying bandwidth extending out +/- 800 Hz. I checked the JST-245 on the
Mark V and got +/- 550 Hz. So it looks as though Yaesu may well have made
some corrections in the Mark V's CW keying circuitry so CW bandwidth is at
the margin of acceptability. I doubt that the Inrad mod would provide any
significant improvement, while W8JI's might, to some extent at least. An
ideal CW bandwidth, as I understand it, is <300 Hz (+/- <150 Hz), so we
still have a way to go. Apparently a number of 1980's rigs by Kenwood and
Icom at least did provide much narrower CW bandwidths.
Anyhow, with these results, I'm staying put with the Mark V. I wonder
when/if the Orion appears what its CW keying will be like? While Ten-Tec
has been good on QSK, its keying envelopes have not been all that exemplary.