[Kenwood] RE: TS-850 or TS-870

[John Geiger]

Haven't used an 870 either, but I can make a few
comments based on what I have seen, and from using an
850:



> > Comparing "stock" rigs, the '850 definitely has
> better selectivity.  The main problem with the '870
> is a lack of good filtering in the front end before
> the DSP chain.  However, there are mods out there
> that add better pre-DSP filtering to the '870 and
> reports are good.  However, the '850 wins due to
> it's "mod-less" nature.

W8JI wrote a column a few months back about this issue
in Worldradio.  The problem with all DSP radios is
that the filtering occurs at the last IF stage, and at
a very low frequency IF.  You have 2 or 3 stages of
distortion occurring before the filtering occurs.  Now
some of the newer DSP radios do have roofing filters
which greatly helps, but the 870 doesn't yet.



> >>> What are average price ranges for one in good
> condition?
> I've seen "good" '850's currently going for $700 to
> $800.  Haven't seen any '870's for sale in a
> while...they're not as common as '850's.  I'd expect
> them to be in the $800 to $1000 range.

I have seen some 850s in the 650 range recently.  The
870s seem to be going for around 1100-1200 right now.

> > >>> What filters or options should be installed? 
> For the '870, check the web for the mod on how to
> replace the stock ceramic filters.  For the '850, it
> depends on your operating modes.  I have one of my
> '850's configured with two 2.1KHz and a 400Hz InRad
> filters, and the second rig configured with a 2.1KHz
> and two 400Hz InRad filters.  I think you can tell
> which rig is for which mode.

One problem with the 850 is that you need to have
equal filters at both IFs to get the slope tuning to
work right.  You can't install narrow filters for both
modes and also use the slope tuning on both modes
because there is only 1 3rd IF filter slot.  I think a
good setup is to install 2 narrow CW filters, and just
use the slope tuning for SSB.  However, the filters
are easy to install, don't even need to take the
covers off, so maybe switch 3rd IF filters between SSB
and CW, depending what contest you are doing.


> >>> Which do you like and why?
> For me, the TS-850.  Better "out-of-box" performance
> and better cost factor.  Most all of the problems on
> the '850 are documented and can be found on various
> websites on the 'net.
> 

I can't see how the 870 would be better than the 850,
as the 850 is an excellent rig.  And I think the
autotuner is better on the 850.  However, I have a
friend locally who just loves the 870. He keeps buying
other rigs, and then selling them because they don't
do as good as his 870-he did that with a PROII and a
Mark V. He does alot of RTTY operating, though.  I
think he plans on keeping his Orion II, though.

> >>> What is the best serial number range to get?
> To avoid the DDS problem on the '850, find a newer
> one.  I believe the old DDS chips were only used in
> the first and second year of production, so serial
> numbers starting with "4" or higher should be fine
> (the first year of production started with the
> number "2").

Kenwood made a major change in the 870 mid production
run, that greatly improved the receive performance of
the rig.  I think it was around 1999 or 2000, which
would be serial numbers 1 or 2, but I am not sure on
that.  
 
73s John W5TD

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