[1000mp] More Key Click Comparisons

[Bob Henderson]

As an owner of two MPs which I use in an SO2R set-up I have read with
interest the discussion on key clicks.  Conflicting information spurred me
to do some tests of my own.

One of my MPs is an early model about 6 years old now, while the other is a
MkV Field I carried back from Dayton last year.  Since I got the Field I
mostly use that as my Run radio when contesting.  That hasn't been for any
other reason than it's the new radio.  I asked my friend George, 5B4AGC if I
caused him any problems with clicks.  George and I end stop each other on
160 metres.  He told me that even at that strength I didn't give him
problems with clicks and he could easily work within 3 kHz.  George uses a
TS870 which he keys with an 6-8mS rise time mostly and doesn't cause me any
problems here.

Last night I had a qso with Jens DL7AKC who is rather a QRQ op.  He told me
that he and DL8LBK had both become convinced they should improve their MPs
by fitting the W8JI mod.  He has done so and concluded that his signal had
improved dramatically in that sidebands from clicks had been significantly
diminished.  He also managed to dispel the concern that the mod would render
the rig useless at QRQ.  He sounded fine and his character elements didn't
appear even slightly slurred.  Jens urged me to check out my MPs on the
bench.

I've collected a number of rigs over the years so I decided I would do a
comparative test which would be interesting for me and maybe to others.  The
test wasn't anything elaborate.  I sent streams of dots into a dummy load
from each of my MPs, TS930S, TS870, and K2.  I used my Ten Tec Omni VI+ as
the receiver connected to my main 15m antenna which I pointed towards the
house.  Each of the rigs keyed at 50W gave me an S9 signal on the Omni VI+.
The receiver b/w was set to 250 Hz.  I tuned either side of the received
signal from each of the rigs in turn, to identify the b/w at which the S
Meter on the VI+ dropped to S1.  The TS870 has adjustable rise time so I
checked it at 2mS, 4mS & 8mS.  I tabulate my findings below:-

TS930                          1.6 kHz
TS870 (2mS)               2.0 kHz
TS870 (4mS)               1.5 kHz
TS870 (8mS)               1.0 kHz
K2                               1.5 kHz
MP MkV Field             2.0 kHz
MP                               3.4 kHz

As you can see the 870 at 8 mS is the cleanest but in truth the 8 mS setting
is rather soft for QRQ and the 4 mS setting is much better for that.

In my view, the 870, 930 and K2 are all pretty good.  The MkV Field is not
that far behind whilst the earlier MP looks really nasty.

It may be that my Field is atypical but on the face of it Yaesu may have
incorporated improvements in it.  I will go ahead and do Tom Rauch's mod to
my standard MP and decide whether to do anything with the Field after that.

73

Bob 5B4AGN, P3F