[Kenwood] TS-870S Test Drive

[Larry, K4WLS]

Don't know that much about the TS-870S, but I have been
using a TS-870 (on loan) for about a year now. It does
have the DSP IC chip update, which I am prettty sure are
the same DSP filter chips used in the TS-870S.

As a CW Op, the TS-870 has probably got the poorest
and skimpiest RX design of any rig that I have used on CW
in 45 years. Same goes for the original production runs of
of the TS-570D and D(G).

(1) No notch filter. Anybody that would make a rig for CW
     and not include a notch filter that is usable in the CW mode
     should be shot.

(2) The TS-870 has got to have the poorest noise immunity
      of any rig I have used. Same goes for the TS-570. Reason
      is no roofing filter ahead of the IF's. In the TS-870, all
      the noise gets funneled into the IF's where the DSP filtering
      takes place. The noise contaminates the DSP filtering
      which renders the 200 and 400 Hz BW settings virtually
      unusable if you live in a QTH which is fairly noisy. My 18
      year old Ten Tec Corsair with just a narrow 2.3 KHz SSB
      XTAL filter will pull signals out of the noise
      with good copy that are barely audible on the TS-870.
      The speced sensitivity of the Corsair in only .25 uV for
       a 10 db S/N ratio with the Preamp on. From memory now,
       think the 870 is speced at .15 uV for a 10 db (S + N)/N
       ratio. Never did agree with the change from S/N to
       (S + N)/N - the latter produces a fudge factor like the
       audio boys who spec a stereo channel at 20W and do
       not bother to tell you it is peak power and not rms power
       at a certain % of distortion.

(3) When a freind of mine bought an IC-756 Pro I, he gave me
      his 1998 production run TS-570D(G) which had a 250 Hz
      stock Kenwood ceramic filter installed. No roofing filter
      here either (also no notch filter for CW). Well, whoever
      came up with ceramic filters for CW should be shot as well.
      Unlike XTAL filters, ceramic filters vibrate (ring) right along
      with the noise. Since the D(G) had 6M capability, the front
      end bandpass has a nice 10 Khz wide bandpass - lovely
      for noise and blow-by with strong adjacent CW signals.

Now, the 870 does have good points. The front panel CW
sidetone level adjust is great - no removing covers or trying
to stick screwdrivers through holes to hit a pot on the inside.
The XMT and RCV audio for SSB on the 870 are great,
(but I don't do Slop Bucket). The 870 has a Logikey keyer,
the best keyer made, and if you are old like me with a shakey
fist, you can turn the automatic character spacing OFF.
Also you can emulate some of the other popular keyer designs
such as the Accukeyer (my favorite) or the old original Curtiss
timing.

On CW the 870 has 100W +++ output on all bands, a nice
quiet cooling fan which is in step with the CW VOX and the
rig runs super cool. The setup for CW split is a bit cumbersome,
don't know why they didn't stick to the traditional buttons which
they did put on the 570, but engineers are often engineered
by the "bean counters".

If you live in a fairly quiet "noise wise" QTH, and can live w/o
a notch filter (unlike me), the 870 would be a decent rig, but
you can probably count on replacing the VFO optical encoder
($ 150.00 just for the unit) in about 3 - 4 years unless Kenwood
made some changes, but I doubt it !!!!

Also the front panel ergonomics of the 870 are decent
(except the split freq buttons). A few other items worthy of note:
The onboard antenna tuner is appropriately marked AT and
not ATT, as it is not very "automatic". It can be bypassed
very easily by hitting one button for using an external tuner,
but you will find yourself hitting the AT button fairly often
when changing freq to keep the SWR 1:1.

Also, unless Kenwood has made some changes, the two
plastic DSP filter knobs have a tendency to crack and
break.

I hear Kenwood is still manufacturing the 870S on "as needed
per demand" limited basis. I personally would be leary of
the word "limited" as quality assurance measures seem to
be "limited" as well on these type of production runs.

Really do not think I would purchase an 870/870S if they
were on sale for $ 500.00.  I used to be a "died in the wool"
Kenwood man. The 520 thru 830S were (and still are) some
of the greatest rigs made. Really a shame, I kinda think
Kenwood is inching out of the amateur radio market. The
TS-2000 was a flop, and even though the TS-50 was a
pretty decent rig, it just didn't catch on.

Of course, the above remarks are just "my" personal
experience with the 870 and 570. I do believe that Kenwood
has added DSP filtering on CW to the 570's now being
made, and if this is true it is a good move.

73,  Larry   K4WLS


From: <STRutledge@aol.com>
Subject: [Kenwood] TS-870S Test Drive


I was in AES in Orlando this morning and tried out a TS-870S.  It sounded
pretty nice.  I am a TS-850S owner with two 500 Hz and one 270 Hz Kenwood
filter
(s) installed.  I operate primarily CW.  The filtering on the 870 sounded
nice
and adequate on CW although the band was in the pits.  AES reportedly had me
on their CC A4S but the signals seemed to be incredibly attenuated.  I could
nothing on 15 meters as well as 17 meters.  Those bands usually have SOME
activity even though conditions are not good right now.  I guess it could
have been
the radio or the antenna.  They couldn't find the manual but I was able to
figure most of it out.  The say the coupon for the $300.00 discount is good
through the end of the month although the discounted price doesn't appear on
the
HRO web site.  Not a bad deal for a radio that was pretty expensive in the
beginning.

BTW, a friend of mine works for HRO and he seems to like the Icom 756PROII
or
whatever version is out there now.  I don't doubt his comments but Icom
scares me to death after all the problems they have had with the 746PRO and
the
910H.  The SN on the 870 I played with was 9xxxxxx something or another.

Steve, N4JQQ
- - -

Your moderator for this list is:
Larry Wilson KE1HZ kenwood-owner@mailman.qth.net

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