[Kenwood] 850 vs 450

[Ron & Madhavi]

Roy....

If I am not mistaken, the 450 has an AF compressor while the 850 has a true
blue RF speech processor. With the 850 and the DSP100, there is a WHOLE NEW
world ahead of you! The secret menus with the 850+DSP!00 combo has
rejuvenated this pair and is the RAGE among audiophiles. I have a 850 with
ONLY the stock 2.7K SSB filter, but with the proper DIP switch combo in the
DSP100, I can open up the RX/TX to a variety of bandwidths from 6K to 2.4K.
Not that it makes any sense but I can even transmit SSB at a width of .5K
!!!! Imagine the 100s of $ one would otherwise spend on optional filters?!
Having said that, my DSP100 was a "deal" at 406$ !

The monitor facility is useful not only to check your speech processor
levels. With the monitor "on" one doesn't have to depend solely on on the
air reports when changing mics, using external audio processing gear etc. In
today's Ham World where lots of folks pay particular attention to audio, the
monitorless trx can be quite a handicap. HOWEVER, I think there is a company
which sells a monitor module for the 450 (Universal Radio?).

You have covered the topic rather well and there is not much else I can add
Roy. BTW, the "high boost" on the 850 works like a charm for working the DX.
It makes the stock MC42 sound as good as a HC4 or better!

Again.....just don't touch a 2xxxxx 850 like I did and got my fingers burnt
and a BIG HOLE in my pocket! Yes, I will not let an opportunity pass to
caution others. Not everyone is rich and lives in a country with repair
facilities around the block! It is sad that Kenwood never admitted this
design/componant failure, but chose on the sly to upgrade from the 6631s to
the 66312s!

73,
Ron, 6Y5/4S7RO

----- Original Message -----
From: Roy Sakabu <rsakabu@pwav.com>
To: <kenwood@mailman.qth.net>
Sent: Thursday, October 23, 2003 11:39 AM
Subject: [Kenwood] 850 vs 450


Hello Bob,
  I've been running a 450 for about 2 years now and just got an 850,
although I've also had a 440, 940, 830 and 870, so I'm sort of familiar with
Kenwood rigs.

The 450 comes with 1 - 12 khz, 2 - 6 kHz, and 1 2.7 kHz filters.  The only
crystal filter is the 2.7 kHz filter which is in the 8.83 MHz position.  My
450 came with an additional 2.7 kHz crystal filter for the 455 kHz position.
When both are engaged, the actual bandwidth is about 2.4 kHz, but I don't
really notice any difference.  To get rid of "monkey chatter" in SSB, all
you have available is IF shift, or else you must buy a narrower IF filter
such as the YG88SN-1 1.9 kHz SSB filter.  The IF shift works fine so long as
you don't have anyone talking on the other side of the offending signal.

     The 800 and 900 series of rigs which includes the 850 has High cut and
low cut knobs which Kenwood calls "slope tuning".  This requires equal width
filters in both the 8.83 MHz IF as well as the 455 kHz IF.  The knobs move
one IF relative to the other which makes the signal narrower on one side
only.  The stock 850 has 2.7 kHz filters in both IF's.  I think the 8.83 MHz
filter is the standard YG88S and the 455 kHz filter is probably a ceramic
filter to cut costs.  You don't need a narrower SSB filter, because you can
narrow down the signal with the High Cut and Low Cut adjustments.  The shape
factor will be worse than a narrower filter because the actual slope of the
attenuation will be the same as the original filter, but most people won't
notice the difference.

     The nice thing about both rigs is that you can use any filter in any
mode.  I've notice that when "opening up" the passband to 6kHz, I can get a
full appreciation of what some people's audio sounds like.  So long as there
isn't anyone else nearby, you can get really good audio from some stations.
With others, it doesn't matter.  I've also used audio DSP's to cut out the
QRM with a 6kHz passband on my rig.  I've used the JPS NIR-12 and Timewave
599ZX and both work very similar to the Kenwood slope tuning or Icom's
Variable Passband Tuning (PBT) function.  Nine times out of ten, the level
of the interfering signal is less than the desired signal, so an audio DSP
works just as well as an IF DSP.

     Even though the displays of the rigs show the limited choice of filter
selection, you can actually put any Kenwood or Kenwood compatible Inrad
filter width in the slot.  For example, if you are a SWL, you can put a
YK88A-1 into the 8.83 MHz CW narrow filter position and select it along with
the 12 kHz 455 position for great sounding AM with good steep skirts or add
in the Inrad 4 kHz filter in the 455 CW position to chase AM DX  stations.

     You can get a visual picture of what slope tuning does by downloading
the 850 manual and looking at page 33, or page 50 of the TS-830 manual which
gives a comparison between IF shift and slope tuning.

     While I just got the 850, I've been studying it for quite a while so I
am familiar with the differences between it and the 450.  Ignoring the
additional CW features of the 850 over the 450, here are some of the
differences that may interest you:

- Variable bandpass tuning on the 850 as opposed to IF shift on the 450.
- Variable noise blanker adjustment on the 850, only NB1 and NB2 for 450,
although I've heard that the 850 NB isn't very good, but can be modified.
The 850 has an adjustable NB1 level and NB2 width.
- 6, 12, 18 dB attenuation on the 850, single 20 dB attenuation on the 450
- 850 has AGC of slow, mid, fast, off.  450 has only slow and fast (no off)
- The 850 allows you to monitor your TX audio, the 450 does not.
- The 850 speech processor is adjustable, the 450 is either on or off.  This
makes the monitor function not really necessary on the 450, you simply
adjust the mike gain while looking at the ALC reading.
- The 450 allows you to clear the RIT/XIT with the touch of a button because
it uses optical encoders, the 850 must be manually adjusted to zero or
turned off because it is controlled by a pot and there is no center detent.
This is a big issue for some.
- As with most Kenwood rigs, "AIP on" means that the preamp is OFF.  This
should be the standard setting rather than keeping the preamp on in the
default setup.  This will result in lower S-meter readings, but much fewer
IMD problems.
- The 850 has the 8.83 MHz IF out in the back.  This is a wide band signal
which can be fed into an SM-220/BS-8 or SM-230 to get a real time spectrum
display of all received signals near your tuned frequency.  Sort of like a
poor man's 756/Pro/2 spectrum display.  It is very handy at locating
stations during contests or Field Day or while SWL'ing or seeing who is
causing QRM.  The 450 does not have this output and the only way you can get
it is to tap into it inside the radio and add a buffer before bringing it
out.
-  The 850 allows you to add on the Kenwood DSP unit, although if you are
going to spend that much, you're probably better off getting a used 756Pro,
870, or TS-2000.
- Obviously the 850 is much bigger and heavier than the 450.

If I've misstated something or if anyone can add anything else, feel free to
do so.


Hope that helps.

73
Roy
AD6ZU

_________________________Original Message____________________

Hi Guys

Thanks to all who have replied on and off list to my post looking for a 450
or an 850.

I'd like to know what the differences in the 2 radios are. CW is not a
concern for me, but being a musician, good audio quality is.

For starters, do both radios come stock with the same filters?  I'm new to
all this and appreciate all the help so far!


thx

bob
- - -

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

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