TopBand: Comparison of TS940 to newer receivers

Tue, 15 Apr 1997 12:35:24 +0000 (GMT)

April 14, 1997

A number of weeks ago I asked the TOPBAND reflector about their 
experiences with newer receivers, and promised to summarize your comments 
and my tests for the group. 

I'm slow in getting this out because I lost some mail messages (including my 
own) but here's what I pieced together:

****Comparison of Kenwood TS-940 to other Receivers****
(This test is aimed at CW reception)

MY ORIGINAL QUESTION (my own comparisons are at the end of the message):

As a died in the wool TS940 user, I've been believing that the 940's receiver 
was as good as I could find for 160 and 80 meter DX CW, short of some of 
the older rigs (like the Drake and Collins stuff). Even though copy is rough 
here in the "black hole" of DX, I have been able to work a number of 
countries on these bands with just 100 watts. Line noise at my place is MAJOR!

Then I visited N9QCT to see his new TS-570 on a trap vertical.  
What I hear on the 570 amazes me. It's early evening, when all I hear at 
home on 160 M is static. And his 570 is dragging in European signals above 
the background noise. When he kicks in noise reduction (NOT the noise 
blanker) the CW sounds like it's a code practice tape! On 160! Not only that, 
but at the 50 hz filter bandwidth (actually about 80-90hz) there was 
practically no ringing. I plan to borrow his rig and try it at my place 
with better RX antennas and the heavy line noise, just to get an apples/apples 

So the question to recent buyers of new rigs is:
Compared to your experience with older "top-end" receivers (like the 940 WAS 
ten years ago) how do the new receivers stack up? I know that audio DSP 
will overload without a mechanical filter as well, and I saw it on Eric's 570 
(he has a 500 Hz filter on order). But what about fully loaded TS570, TS870, 
FT1000MP, Omni VI, etc? 
What differences do YOU notice?

(R4C about same as TS940, per AA1K)

I'm a 940 user too, in a high noise urban area (1000 feet from Amtrak line 
and major power transmission line, etc.) but have an array of Beverages 
that help overcome the noise. I've not had anything newer here to compare with, 
do have an R4C with Sherwood mods and find it about neck-and-neck with the 
Also use a DSp 59+.
73/Jon AA1K
(Fixing the 940, from KM1H)

T'aint nothing wrong with the TS-940 that a little work won't cure Mel.
Depending upon the serial number ( 8 Million a rough cut-off) there are
many to some mods that really help. Private E-Mail me for specifics.

Also by changing about 45 diodes over to PIN's there is a dramatic
performance improvement in RX performance. I also use cascaded IRCI
filters for both CW and SSB...the Kenwoods have poor skirt rejection. 

I have 4 940's here that are used fm HF thru microwaves as platforms for
transverters. I quickly sold a FT1000D as not worth the money that 2 well 
modified 940's could perform at. 

I had a TS870 here on has a great RX but very prone to overload on 
40 thru 160. 

GL and 73    Carl  KM1H   261 DXCC on 160;    309 on 80
(Comments from George Guerin..K8GG)

     1. My experience with the TS-940 is it does not hear as well as the 
 TS-930 or TS-950SDX.  Also there is generally a spike on the leading 
 edge of the first CW character sent which risks grid damage to tubes 
 like the 8877, 8874, 3CX800A7, etc.
     2. Your description of the TS-570 sounds very good.  Maybe they will 
make a TS-970 soon??
     3. I hear there are problems with the TS-870, because there are no 
filters at all, except digital in the last IF.  This creates birdies 
in the pass band, since it is at something like 14 or 17 Khz, and a 
signal 28 or 34 Khz away can leak through.  I hear one W6 added 
filters and cleaned the birdies, but Kenwood will not do this on 
production units, so we will have to wait for a TS-871 or 880?
     4. I have used the FT1000MP and it does a pretty good job, but I 
haven't put it side by side with other radios.  Setting the two DSP 
controls on the concentric rotary switches is a bit tricky.  The dual 
receive and or split is very good and easy.  A friend in Chicago says 
it hears better on CW than the FT1000D and the TS950SDX.  On phone I 
like the TS950SDX best, but that is not true 160 operation.
     5. I would like to try the IC-775.  More money, but the automatic  
carrier null is very fine.  On CW, I would like to try one on 160 for a 
while myself, and see about the noise removal system.
     6. I understand TenTec has a Omni 6+ just out with dsp.  I have no 
way of trying it and the TenTec "chemistry" and my body chemistry do not 
get along, so I will never buy one.  I do have friends on 160 with 
Omni 5 and Omni 6 radios doing well.  They do have good beverages.  
One has a directional vertical array!!  I do have a TenTec tuner I 
like a lot.  There is no chemistry problem without electronics inside 
the box!  HI !
     George Guerin
[NE3H compares the 940 to the Omni VI (not the VI+)]

On the OMNI .. no question, best receiver that I've ever heard.  Yes, 
I think the FULL DSP receivers may be more sensitive ... or have lower
noise floor .. but none of the HAM gear that I am aware of ..

I cannot hear the diff between my old 940 and the OMNI .. if normal
ambient noise, most people cannot hear the diff.  The outstanding
characteristic.. and the second reason I got TWO OMNIs .. is that you
can have an S9 + 20 signal next door to one in the mud .. and it does
not make a difference.  I have a neighbor .. a mile away .. who runs a
kW on RTTY .. ( as do I ) and we can op within a Khz or two without
disturbing each other.

Fact is, if you have lots of line noise .. I don't think you'll notice
the diff in rcvr sensitivity.  The noise blanker on the OMNI is about as
effective as any .. but I don't think it is better than the 940 re noise
blanking.  But Yes .. the front end does not 'Block' in the presence of
a loud signal next door ...

The second reason that I went for the OMNI is that it's signal on CW /
QSK ( at high speed ) is distinctly better that anything else .. save
the Icom 781 that I've heard anywhere else.  

The fact that you can cascade filters on the NEW OMNI PLUS really makes
me twitch .. I've already signed up to do the full upgrade to my radios.
I have a 500hz RTTY filter in the 9mhz path .. after the mod .. I'll be
able to have a choice of the RTTY filter or the CW filter .. I think that is 
a real advantage .. 

Of course, stacking of filters is pretty nice on the FT1000 stuff too ..

The OMNI operation is pretty intuitive too .. it has less bells and
whistles .. but I can't think of any I miss ( from the old 940s ).

Remember that 98% of my operation is CW and RTTY.

de joe
(comments from K3SME)
Were you able to borrow the rig and try it at your QTH?  I have found
that 160M performance is very QTH specific.  I have borrowed "goodies"
like DSPs which knocked noise down ALOT at my buddy's QTH but didn't do
much for my noise here as an example.  One of the locals here in
Maryland picked up a 570 about 2 months ago and after a week said it was
pretty good but he HAD to get the optional filter to make it decent on
low band CW for receive.  Have you had other comments?  The few guys I
know with OMNI V and VI praise them highly for low phase noise and
tremendous RX capabilities.  I am using a TS830S.  It replaced a Drake 4
line. Tough to keep up with technology and I refuse to pay for a 100
memory tranceiver when I don't need all those bells and whistles.
73, Sid.
(K8GG asks about the 570, comments on TS950)    
Have you read the review by Doug DeMaw, W1FB in the March 1997 issue 
of CQ Magazine?   It reads well but raises the questions I have 
written here below:
1. I wonder if the only way to get a beverage hooked up is to change 
antenna selections on the front panel?
2. I also wonder if there are plug in slots for more than one extra 
filter?  I don't need a 1.8 Khz SSB filter with slope tuning, but I 
would like to have both the 500 and 270 Hz filters in the 8.8 MHz IF.
That is one complaint about the TS950SDX:  There is room for both the 500 and 
250 Hz IF filters in the 455 Khz IF, but only one CW filter in 
the 8.8 IF, and it is more important to have selectivity in the first 
possible stage (2nd IF) rather than in the next stage (3rd IF).  
Obviously, it does not have the DSP available in the TS570!
I may send Doug an SASE and note and see what happens.  He now lives 
maybe 175 miles NNW of me.
     73         GL              George          K8GG
(Another comment from K8GG George Guerin)
As I saw the TS-870 show at the W9DXCC a couple of years ago, there 
are NO IF filters.  That model uses digital filtering at about 17 Khz 
to shape the passband.  Problem is the images 34 khz away!
There is no plan to put in filters, although a couple of California 
hams have done it.  (WONDER WHO?) With out a 2.7 Khz filter at the 8.8 or 455 
IF, it has troubles from what I know.
Kenwood is NOT planning to make filters optional.  I do understand 
using the SSB filter and digitally making the CW filter in the 4th IF 
works fine.
On the TS-570:  Is there an accessory socket like the TS-940 and 
TS-930 that has the ability to pull out and put back in the RX antenna 
That is my fear!    The Icom radios like the '740, '751A, '765 and 
'775 all have a coax jumper for the RX antenna line.  The '728 and 
'726 do not!!  I complained to the Icom rep's at Dayton.
The TS-950SDX has a jumper like most of the Icom radios.
There is a guy in Ft. Wayne who makes FEP's - front end protectors. If you 
can figure a way to bring out the RX antenna line, it is a neat 
way to make sure the RX input is grounded on transmit.  It is written  up, 
but not in enough detail, in one of the recent CQ Mag's as well.
That might help, but toggling the front end on each "over" is a true 
Have fun,  73   George

MY OWN TESTS, Side by side with TS-940... KJ9C

>From what I saw of my friend's 570, and from his comments, the CQ article is 
on the money
To switch antennas one must MANUALLY hit the ANT switch... so that's one 
hit for transmit, one to receive when using a beverage... I have not yet 
looked for a transverter input on his rig, as that is how my TS-940's 
external RX antennas are wired,... when I get the rig at my place I will 
check for features... but I know there is NO dedicated RX antenna 
input... this would keep me from buying a 570, but I guess I could build 
an external TR switch like we built back in 1968 for club's S-Line.
There is room for only ONE filter... so decide whether it's SSB or CW, 
500 or 270... that's a big drawback but would not keep me from buying a 
570, as I would likely go for the single 270 for IF protection... but one in 
each IF would be nice... I guess the TS870 has room for NO IF filters

Written later:
I borrowed the 570 for a few hours and installed it with antenna switching 
next to the TS940 at my NOISY QTH (line noise on some antennas as high as 20 
dB over S9). In every case the 570's noise REDUCTION unit did a better job 
of reducing noise and bringing up weak signals (most tests on 160 and 80 
meters where my noise is worst). The noise blanker also worked, but the digital 
reduction was better. On the contrary, the noise blanker on the 940 seems to 
be a little better than the 570's. 
However, as you know, strong signals tend to swamp receivers with noise 
blankers ON. The 570 noise REDUCTION beat the DSP59+ NR feature.

The 570 was tested without an IF filter installed, and it did exhibit some 
overload from adjacent signals... since then, Eric has installed a 500 Hz 
IF filter and reports that adjacent signal swamping is negligible, and he can 
crank the DSP down to 100 Hz without ringing.

The DSP is the selling point of this receiver... better signal to noise 
than the 940 (with STRONG noise) and therefore can dig out the weaker ones. 
However, in the absence of strong line noise (say S3 or lower) the TS940 
with outboard DSP seems to work pretty well. See below.

The CW autotune works with relatively weak signals, but not down in the 
mud. This makes tuning with tight bandpass a lot easier.

Very little SSB testing, but the heterodyne filter works as good (or 
better) than the one on the 59+ DSP. Did not have multiple heterodynes to 
see how it works, but would guess OK.

Forgot to check for transverter input!!! Dope! Suppose that auxiliary 
receive antenna is possible somehow. 

I borrowed K9IG's 1000MP for similar testing. I felt like I should sign 
away rights to my firstborn grandchild if I damaged it, so better believe I 
was REAL careful with it and read the manual first!! But Greg seemed 
unconcerned that I was driving away with HIS 2500 dollar radio in my truck.

I set up similar to the TS570 test, and as luck would have it the power 
company chose to temporarily fix the line noise (after five months!!!) that 
day. With all the mechanical and DSP features kicked in (including a DSP59+ on 
the 940), the TS940 and the FT1000MP performed about the same on 160 through 
the other bands (CW only tests). Some of the controls WERE tricky, and the 
preset filters on the 1000MP took some getting used to. There must be about two 
million bells and whistles on the 1000MP, and my fat fingers found a few by 
accident. It is an impressive rig... but without line noise, not enough to 
make me dump the old 940. Without the noise reduction, the 940 is OK.

One thing I noted... small point... S meter readings were comparable for both 
rigs at low signals and noise levels... but S meter readings were higher 
on the 940 for stronger signals... of course, that does not mean much, as an 
S meter ain't that accurate... just needed more attenuation with 940.

I packed up the 1000MP and got it ready to take back to Greg (about 8 miles 
from me)... then Indianapolis Power and Light came through just in time!!! 
Line noise returned, but only at S9 levels. I quickly patched the 1000MP 
back into the setup and compared reception. In this case (with strong line 
noise), the 1000MP was better at pulling weaker signals up out of the crud. 
Even with noise blanker on, the 940 lost some of its ears. Noise blankers on 
both rigs eliminated the noise HEARD, but the 1000MP was better at finding 
signals and bringing them up than the 940 with DSP59+ was.

4/15: Bill Tippett reports that his 1000MP is extremely clean (no 
intermod products observed) compared to the TS930 he retired.

I wanted to test an Omni VI+, but none to be borrowed locally, so I asked 
NE3H for his opinion (see above). In the meantime, power company has repaired 
a number of defective lightning arresters, a bad transformer, and God knows 
what else to the point where my line noise is now S3 or less most of the time..
so the 940 gets a reprieve.
I fact, even though it's almost too late in the season, am working DX on 160 
most evenings now when I could not hear it in winter!!! With a little 
luck I might hit 50 countries for the 96-97 season.

I wish I could find the mail messages I sent to George because there was more 
specific info in them... but this report is the bottom line. From my 
own observation, the 1000MP and the TS570 outperform the TS940 receiver with 
high line noise levels. Mechanical filters are needed on both rigs. But with 
little line noise the 940 is still pretty dang good.

Thanks to K9IG (formerly KO9Y) and N9QCT for the loan of their rigs.

Mel KJ9C

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