K1TTT Technical Reference

One noted lack in the TS-870s is the missing beverage antenna input. There is a relatively simple fix for this using an external relay. (schematic) 

TS-870s Notes: 

This is extracted from my message posted to the YCCC and CQ-Contest mail reflectors. 

CQWWSSB comments:
Well, the first contest on the new TS-870 is history.  We used it on 
20m driving an Alpha 77 with the 6/4/4 150' high stack here.  While there
were some critical comments it didn't stop them from making over 2200
QSO's over the weekend.  Below are some of the operator's and my own 
first impressions.  We did not do a side by side comparison during 
the contest, nor did I have time to do much comparing before the 
contest.  The comments below are therefor all based on operator 
impressions rather than measured characteristics.
First impressions:
1. They still don't know how to do a bev antenna input.  But I bet that
the ant-2 input could be made to work as bev input with just a change in
the proms.  don't be fooled by that 'rx ant' rca jack on the back, it is
only an output for a second rx.
2. The menu items and agc interact quite a bit when playing with the
DSP noise reduction.  Some settings can cause extra noise if you don't
take care of what you are doing.  When set properly the noise reduction
is great though.  (This is from non-contest playing on 10, 20, and 160m.)
3. Vox delay is on front panel which is nice, but the gain setting is
on a menu selection.  It doesn't seem real critical though since it also
uses some dsp function for vox generation.  I don't think anyone had to
touch the vox gain menu item the whole contest, even with a couple
different ops using it.
4. The cw filter width and ssb high and low cuts don't track the vfo
selection.  That is, you can't have a different width or filter selection
on each vfo.  This is something that could probably be changed in a
prom update if there is enough call for it.  This was a comment from
a DXer who thought it would be nice to be able to have a real narrow
setting when listening to a dx station and a wide setting on your tx
vfo to hear more of the pileup when setting the split.
5. It seems to work just fine with CT-9.26, just tell CT that it is a
TS-850 and set baud rate.  The TS-870 defaults to 9600 baud instead of
4800, though this can be changed in a menu setting.
6. It was very easy to have a second radio on the same band.  The TX 
noise from the TS-870 seemed much lower than with a TS-940.  Also the
870 RX tolerated the strong signal from the second transmitter very well
as long as it was a reasonable distance up the band.
7. Two of the operators complained about what one of them described as
AGC 'overshoot' from nearby strong signals.  This may be correctable by
playing with some of the other menu settings.  This might also be an
effect caused by the extremly sharp cutoff of the filters.  You virtually
don't hear someone creeping up on your frequency until they come blasting
in.  It seems to me there is no middle ground, either you don't hear 
the nearby QRM or you are getting blown away by it.  I would like to 
hear from anyone that has tried to compare this close in interference to
other radios, particularly the TS-930 or TS-940.  And would like to hear
from other TS-870 owners if you found any particular setup that helped
prevent this problem.
8. The Auto-Notch does a super job of getting rid of QRM from someone 
tuning up on you.  They just virtually disappear.  The beat cancel seems
less effective, but does help in some situations.
9. Neither the noise reduction filter nor the noise blanker could handle
the rain static we had for a while.  More playing with settings on these
might help, but switching to a lower antenna was faster at the time.  I
will play with this more later to see if there is a setup that will get
rid of that random impulse noise.
10. It ran with an Astron 20A power supply just fine the whole weekend.
11. I played a bit with the mic equalization stuff.  You can indeed change
the audio around quite a few ways.  We did not play with this during the
contest since the audio from the HC-4 mic with just a bit of compression
seemed to do just fine.  The chart showing the various effects of 
combinations of settings for the equalizer is a bit confusing at first.
Maybe it would make more sense if you were an audiophile and wanted to 
sound like a broadcast station.
12. We have not done much playing on CW yet, probably more on that after
SS CW next weekend.  But in just playing around mostly on 160m the CW
filtering seems superb.  Even at 50hz bandwidth the filter doesn't ring.
It was described by one operator like listening to code tapes.
CQWW CW Comments:
The first CW contest has been run using the TS-870 here now.  Results
seem more favorable on CW than on SSB.  Specific comments follow:
1. Getting used to the filtering took a bit of practice, the skirts 
are so sharp that signals disappear or appear very quickly while 
dialing across them.  Going down to 50hz bandwidth is amazing when you 
want to separate close signals, but I wouldn't recommend it for running.
It might be nice to have a smaller step in bandwidth settings.  It seemed
some times that 400hz was too narrow, and 600hz was a bit wide, I don't
think we ever when to 1khz except when scanning to see if the band was 
open late at night.
2. The first time we really got on the band with lots of loud signals 
I thought something was wrong.. there was chopped up CW and odd stuff 
all over the place, turns out it was massive mixing products.  Turning 
on the AIP (advanced intercept point) made it all go away, of course 
this also reduces sensitivity to weak signals.  But when even the left 
coast QRP guys are loud it doesn't matter too much.  The pronounced 
appearence of the mixing products was very confusing at first.  I played
with the AIP settings a bit, turning on the AIPGAIN function in the menu
seems to restore some of the sensitivity without bringing back the 
mixing products.  The manual talks about the AIPGAIN function restoring
s-meter readings to normal, but it also seems to boost the RX gain.  I 
will have to play with that some more to see what the real effect is.
3. The TX is VERY clean.  I was able to copy moderately strong signals
within about 5kc of the 870 tx freq on a ts-930 with a tribander about 
300' from the 20m tower.  With the same radio I couldn't copy anything
on 15m where the tx is a ts-940 and the tower is about 200' from the 
CQ 160 CW Comments:
During the CQ 160m CW test we were attempting to use two radios so we
could listen on one and run on the other.  It was working fairly well
until at one point we must have gotten too much RF into the 870's
antenna jack.  The RX on the 870 lost most of it's sensitivity (read
this that we could only barely hear a couple stations on the band).
After several minutes of troubleshooting I determined that there was a
small bulb in series with the reciever that had opened.  It looked like
it was in a socket, but it turns out that it was just soldered into a
plastic carrier that is surface mounted to the board.  The investigation
also showed that the "RX ant" jack on the back has a similar bulb plus
resistor in series with it.... plugging the beverage cable into the rx
ant jack restored the 870's RX for the rest of the contest.
The location of the bulb is not very easy to get to without removing the
board (its under the back lip of the case) and i wanted to have the rest
of the rx checked out so i sent it to groton electronics for repair.
the technician there says the part is a new one and he didn't know when
he could get it, or even what the cost would be (it would be covered
under the warrenty anyway).  In order to get it back on the air by the
ARRL DX tests he swapped the bulbs so now the rx ant jack doesn't work,
but the regular tx ant does.  He is going to send me the bulb whenever
he gets it in.
I think it is interesting that they now build in protection like that, I
just wish the bulb was in a socket, or at least easier to get to.

K3BU modification:
TS870 external receive antenna switching 
Kenwood TS870 has two antenna jacks ANT1 and ANT2 and external receiver
antenna jack (RCA type) that can accommodate external receiver when activated
through the program menu. This adds some attenuation to TS870 receiver
signals. There is no provision for external receive antenna switching
(Beverages, preamp., etc.) When I inquired Kenwood about this option, they
sent me modification instructions that required cutting the traces and
rewiring the ext. RX connector. When I received my Service manual and had a
look at the circuit, I came up with this simple modification:
Parts needed: 1 diode (any type) I used rectifier diode, generic NTE125
Step by step instructions:
1.  (In the following references the front panel of the rig is facing you.)
Remove the top cover.
2.  Remove 7 screws holding the cover over the FILTER and RELAY unit (in the
middle) and remove the cover. (Where the ANT1 and ANT2 connectors go.) This
exposes two PC boards.
3.  Locate the connector CN301 on the RELAY unit (adjacent to ANT1 and ANT2).
It is about 1 inch back and 1 inch left from the ANT1 connector and has three
wires going to it - two gray, left and one black, right.
4.  Take the diode, clip the leads to about 0.5 inch length, bend them down
and form them so the are spaced about 1/8" and parallel (kinda forming letter
5.  Plug the diode into CN301 connector from the top, pushing the diode wires
between the plastic housing and the metal contact of the connector. Cathode
(the end with the band marking) of the diode should go to the middle contact
(gray wire), the other end to the left contact (gray wire). Make sure that
diode makes good contact with terminals of the connector. Black wire should
be free.
6.  That completes the modification. Replace the covers, do not pinch the
wires going to the antenna tuner!
Connect your transmit or main antenna to the ANT2 connector. Connect your
receive antenna or preamp output to ANT1 connector. Now you can transmit only
through ANT2 connector. 
Front panel button ANT now allows you to select ANT2 (receive/transmit on
ANT2) or ANT1 (receive on ANT1, transmit on ANT2). Antenna tuner would always
see the impedance on ANT2. The way the switching works, whenever you
transmit, you will switch ANT2 on transmit, regardless of ANT1 or ANT2
selection. Much better use of connectors than originally devised by
"knowitalls" at K...d.
Notes on TS870 usage: Normally there is enough gain on the receiver for
beverages. In case that you need to use the preamp or preselector, than turn
the AIP on TS870 on, and if needed add the attenuators. Try to keep the noise
level peaks close to low end of the Smeter scale. Helps with intermods. If
using DSP, play with different settings and different levels of AGC setting,
it has effect on overall behavior. 
I am still looking at ways to improve the filtering in TS870. Knowitalls at
Kenwood tell us that you have all the selectivity you need with revolutionary
DSP, but when you check 50 Hz bandwidth on CW, it is more like 200 Hz at the
bottom of the curve. They still don't get the shape factor importance!!! They
use cheap ceramic filter at 455 kHz IF. Not much room for additional filters.
But I will keep digging inside, see what I can come up with. Strong signals
within crystal filter bandpass and outside of DSP/selectivity still cause bad
TS870 looks like great contestpedition radio, it's light, fits in carry on
luggage. I got speech module for phone CQing and small switching PS for it
($160). I still miss the tunable audio peak filter and ability to go lower
than 400 Hz on CW note.
Good luck and I am not responsible for any goofups you make!
Yuri Blanarovich, 
K3BU, VE3BMV, P40A, one of N2EE

Overload reduction mod:
Hi, John.
It took a little doing, but finally located the chip resistors and the 
information about the changes. The following is the Service Technical Report 
(wording as transcribed from the report):
MODEL TS-870S (~S/N 712xxxxx ONLY)
NOTE: the changes do not apply from S/N 801xxxxx because production has been 
If there is any large power input signal in the proximity in the CW mode in the 
low band (such as 3.5MHz and 7MHz band), it will cause mutual modulation to 
create a "ghost" signal.
It may occur in the contest operation or during the pile-up reception.
A larger power input signal causes the second mixer output, the NB amplifier 
input, and the third IF amplifier input, and the third IF amplifier output to be 
Change the gain allocaiton of the IF stage to raise the limit of saturation. 
This countermeasure will cause almost no deterioration of receiving sensitivity.
Antenna, amplifier, mixer, 73.05MHz filter
Amplifier, mixer, 8.83 MHz filter ----->noted gain is -10dB (minus 10)
Amplifier, mixer, 455kHz filter
Two Amplifiers------------------------->noted gain is +10dB (plus 10)
XX4-3210 (A/9) RF UNIT
        R1157          :  1.8k --->   560     (RK73FB2A561J)
        R160,R161:     :  2.2k --->   1k      (RK73FB2A102J)
        R164           :  1.5k --->   560     (RK73FB2A561J)
        L76,L79        :  3.3uH--->   0(zero) (R92-0670-05)
        R169           :  1k   --->    330     (RK73FB2A331J)
X57-4620  TX-RX UNIT
        R332           :  2.2k --->   6.8k    (RK73FB2A682J)
Do not forget to perform the re-adjustment of the S-meter after taking the 
countermeasures. Refer to "8. S-meter adj." on P.95 of the Service Manual for 
how to do it specifically.
If you cannot adjust the display to "05", even after you follow the steps 
described in "8. S-meter adj.", change the resistor as instructed below and make 
the re-adjustment.
X57-4620  TX-RX UNIT
        VR-1           :  470 --->    3.3k    (R12-6737-05)
There are then drawings showing the locations of the parts on the schematic and 
on the related PC boards.
Hope this helps! Maybe this plus the software changes will take care of the 
majority of the problem. Now to locate and acquire the software.....
               73, Tom, N6BT
               Force 12 Antennas and Systems

Tweaking the service menus



TS-870S Service Menu Setup Tweaking v1.1 (13 Oct 2000)


Hello. My name is John, my call is CT2HME and I live in Lisbon,

the capital of Portugal.

For some time now I own a Kenwood TS-870S.

I have been playing around with the service menu on this rig for a

while. The information on this menu is scarce and people are usually

afraid to tweak this menu.

What you are about to read is pratical information on the TS-870S

service menu that may help you to take better advantage of this rig.

Before start reading this information please note the following:


1. I don't work for Kenwood and they didn't gave me any information.

2. The information on this article *can* cause damage to your radio.

3. The information on this article *will* void the warranty of your


4. Before your TS-870S leaves the factory, Kenwood has aligned your

rig (I hope they also did that to mine!). If it's working properly

*do not* tweak the service menu.

5. I will not be held responsible *in any way* for damage that you

do to your TS-870S. Use this information *at your own risk*.


I'm sorry, but I had to say this.

Now, let's start.


The TS-870S service menu has 28 items. Each of this items has a

function and each function will allow you to control different parts

of your rig.


Each menu has a hexadecimal identification (from A0 to BB).


All this items are stored in a EEPROM that is read each time you turn

on your TS-870S.


The service menu allows you to change the settings of this EEPROM by

writing data on it.


The 28 items are the following:


A0 - System

A1 - ALC

A2, A3 and A4 - S-meter (SSB)

A5 and A6 - Filter

A7, A8, A9 and AA - Power Adjustment

AB, AC, AD, AE, AF, B0, B1, B2 and B3 - Tx Gain

B4, B5 and B6 - ALC meter

B7 - SWR Protection

B8 - SWR meter

BA - System

BB - Display


You can acess the service menu on your TS-870S by doing this:

Turn off the radio (using the [POWER] buttom).

Press, *at the same time* the [N.R.] and the [LSB/USB] buttons.

*While pressing* [N.R] and [LSB/USB] turn on your rig by pressing the

[POWER] button.

The "Hello" message will appear on the display.

You can realease the [N.R.] and the [LSB/USB] button when you see the

"Hello" message.

You should enter the service menu.


To leave the service menu and to return your rig to the "normal"

operating condition, you can do this:

press the [CLR] button *or* turn off your rig by pressing the [POWER]

button, and then turn it back on by pressing *only* the [POWER] button



If you are unable to enter the service menu of your rig read the

instructions above again and do each step slowly.



Before tweaking *any menu* make a clean register of *all* the values

on each menu. This way, if you mess up something, you can allways go

back by using the original value.

To do this, grab a piece of paper and once inside the service menu use

the [M.CH/VFO.CH] button to go through the menus one by one.

*Do not touch any other button!*.

Start with A0 and make a note of what you see. Turn [M.CH/VFO.CH]

clockwise and you will go to A1. Make a not of A1. Repeat this

procedure for all the items until you reach item BA. Item BB is

impossible to copy (you will see why when you are there).

WARNING: *Do not* skip this procedure.

Another thing: I have found that different radios use different values,

and this makes sence since there are *allways* slight differences in

similar equipments.


Now, let's see what each item is for.


A0 - System


This menu will give you the EEPROM checksum. The TS-870S service manual

says that it's the "Program Version Confirmation".

On my TS-870S, it reads:




This menu can not be changed using any key on the front panel of your

TS-870S and it will not affect the performance of your equipment.

Older rigs may have different values for the EEPROM checksum. To my

Knowledge this is the lastest firmware version available to the 870S.

Some hams have reported that major DSP upgrade was made to the 870S

before the release of this EEPROM version. Any comments?


A1 - ALC


This is a sensitive item and it will adjust the reference voltage the

microphone ALC.

If you take a look at the service manual, the correct procedure for

adjusting this menu is to connect a well calibrated digital volt meter

to test point 2 (TP2) on the RF board (X44-3210-00) (A/9).

When measuring TP2 on the RF board the correct value will be 2.70V.

To adjust this value use the [RIT/XIT] button.

In my case, measuring TP2 for 2.70V lead me to a value of 89.

Your rig may lead you to other value. By the way, to measure TP2 you

will have to remove the bottom cover of you rig. I advise you not to.

So the original reading on my 870S was:


A1 89 89 ALC REF


But, I am not using 89. After trying out different values for the ALC

I felt confortable with FF.

To change to FF do this: turn [RIT/XIT] clockwise until you get this:




A1 is the menu number; FF is what you want; 89 is the original value;

ALC REF is the description of the A1 menu.

Now, we want to keep the FF value. By pressing the [UP] key you will

get this:




So you transfered the value you want (FF) and placed it over (89).

89 is no longer valid but it's not saved yet.

If you want to save this value for good, you will have to go into menu

BA (use the [M.CH/VFO.CH] key) and press the [UP] key to save *all* the

new information into the EEPROM.

After saving the info on the EEPROM turn your rig off using the [POWER]

button. Turn it on again (use the [POWER] button) so the new settings

can be read from the EEPROM.


When I said "*all* the new information" I mean that each and every menu

that you have changed will be saved.

My advice is: change one item at a time and try out that item in

particular. If not happy, go back to the original value.


In my case FF led me to a louder audio an to less shack noise into the

microphone. Something that might be to worry is that fact that for the

FF value, the reference voltage will be higher than 2.70V. I don't know

how much higher because I haven't measured it but I have been working

with this value for quite some time and *my* rig works fine.


Ayway, let's supose that you are unhappy with FF an you want to go back

to the original 89 value.


Just do this: go into menu A1 and turn [RIT/XIT] conterclockwise until

you get this:




Press the [UP] key and you will get:


A1 89 89 ALC REF


Now go to menu BA and press the [UP] key to record changes into the

EEPROM. Now turn off the rig and turn it on again and you're back to

the original setup. Easy, right?


A2, A3 and A4 - S-meter (SSB)


The S-meter was the reason that made me tweak the service menus in the

first place.

On it's factory configuration my rig's s-meter was (most of the time)

way bellow signal 9. Even with AM broadcast stations running several

kilowatts I was unhappy with it because it was very difficult to go

over 9, into the red area where 9+20, 9+40 and 9+60 dBs signals are


To adjust *properly* the s-meter you will need to generate some

voltages. They are: -107dBm (yes, this is a voltage! It's just

expressed in different units) for signal strenght 1. Then you'll

need -81dBm for a 9 signal. Finally -23dBm for a full scale signal.

This voltages are in the range of a few microvolts. After all that is

what we get from our HF antennas.

This voltages will have to enter the rig trough the antenna connector.

Keep in mind that if you try higher voltages in this input you will

damage your rig.

Some hams out there have bench equipment capable of generating this

voltages. Most of us can't do this, so here is what I did to adjust

my s-meter:

The original values on my 870S were:


A2 xx 05 S.SSB.S1

A3 xx 60 S.SSB.S9

A4 xx 80 S.SSB.FUL


You can take a look at this values by going into menu number A2, A3 and

A4. If you leave the antenna on and you have your rig on a SSB signal

(any band is ok) you will see that the left numbers (above marked xx)

will allways vary. This is normal and it's just your s-meter varying.

Since we want to get stable numbers on the left xx so we can copy this

numbers into the right side (on top off 05, 60 and 80) we would need to

disconnect the antenna and inject the user controled microvolt voltages

until we have what we want.

The problem is the lacking voltage generator.

Here is a work around: connect a 50 ohm dummy load into the antenna

connector. Turn the [RF] button fully clockwise.

If you are away from strong RF fields, now your readings must be:


A2 00 05 S.SSB.S1

A3 00 60 S.SSB.S9

A4 00 80 S.SSB.FUL


In my rig weak signals were fine, so I left A2 alone and I changed only

A3 and A4.

I placed 30 in A3. You can do this by going into menu A3 and turning

the [RF] button *slowly* conterclockwise until you have this:


A3 30 60 S.SSB.S9


Now, just press [UP] and you will get this:


A3 30 30 S.SSB.S9


For A4 I used a value of 60. So, using the same procedure, just get



A4 60 80 S.SSB.FUL


then press up and you have


A4 60 60 S.SSB.FUL


To save your changes go into menu BA and press [UP].

Now your s-meter will be much more sensitive and you will give better

signal reports. :-)

Please notice what I said before. This is not a scientific way of

calibrating the s-meter. The right way to do it is to generate the

right voltages and place them into the antenna connector on the radio.

This is just a rough aproach that worked well in *my* case.


A5 and A6 - Filter


I haven't messed up with this so I can't help you here.

Anyway if you want to change this on your own (and tell me about it

latter on) here are the original values on *my* rig and the keys for

changing this values:


A5 00 00 8.83 FIL

A6 00 00 455 FIL


The [RIT/XIT] button will change the 00 left values between -99 and 99.

The [UP] key will place the left number into the right number.

Pressing [UP] on the BA menu will save your changes.


I have spoke to a great deal of TS-870S owners and just a few had made

changes into the filters on this rig by placing in good quality filters

(INRAD filters for example) instead of the stock filters. While the

reports on the increase selectivity of rig seem to be true, I have been

advised that the transmisson audio will loose quality because the TX

bandwith will decrease.

Any info or comment on this subject is welcome.


A7 to AA - Power adjustment


Rumours say that this rig can go up to 150W.

My first comment on this: *if* it is capable of that and if you care

about you radio *do not* increase the power to 150W. I think that you

can damage the finals.

In it's factory configuration my TS-870S maximum SSB power was 95W.

I pushed the power a little higher into 110W (for driving my 2x3-500Z

HF amp).

You will need a *calibrated* HF watt meter to do this. A Bird 43 will

do just fine. Other calibrated HF meters will do.

Connect the power meter to the antenna connection of your rig. Then

connect a 50 ohm dummy load *capable of handling more than 150W* to the

power meter.

Go into A7. Press [SEND] and using [RIT/XIT] calibrate for 100W or your

meter. When you're done press [SEND] again to stop transmitting.

The usual [UP] key will upgrade your value into the left number.

Going into BA and pressing [UP] will save your settings.


Before saving A7 I would advise you to ajust A8, A9 and AA. The

procedure is identical. Make sure that you adjust A8 for 50W; A9 for

25W and AA for 11W (no, it's not a bug. I read "11W" on the service

menu. If it's 10W and not 11W then the service manual has a bug!).


Then go to BA and save your changes.


AB to B3 - TX gain


If you adjusted the power off your rig you should also adjust this


AB to B3 will adjust the TX gain on each band:


AB - 1.9MHz band

AC - 3.5MHz band

AD - 7MHz band

AE - 10MHz band

AF - 14MHz band

B0 - 18MHz band

B1 - 21MHz band

B2 - 24.5MHz band

B3 - 29MHz band


*WARNING*: I haven't found a way to return the settings on this menus

to their original factory values. Actually I don't think there is a

procedure for that. If you know how to this please contact me.

So, be carefull tweaking this menus. Once they are changed, *there is

no turning back*.

Here's how to adjust the TX gain for menu AB. The procedure is the same

for all the other menus (AB to B3).

Go into menu AB. You should see something like this:


AB 61 61 TxG 1.9M


Make sure you have a 50 ohm dummy load connected to your rig's antenna


Now, press [SEND]. You will see the left number changing. When the

adjustment is complete you will ear a beep. Press the [SEND] key to

stop transmitting into the dummy load. The left number must have

changed. Supose that now you have:


AB 72 61 TxG 1.9M


Now press the [UP] key to get the number into the right side. This is

what you get:


AB 72 72 TxG 1.9M


Go to BA and save the data by pressing the [UP] key, but do this after

ou have adjusted the TX gain for all the bands.

If you try this I would like to know about your results. I tried it on

mine and it's working fine on all bands.


B4 to B6 - ALC meter


The ALC meter seems to be very sensitive and with my MC-60A microphone,

in SSB, with volume at number 6 it saturates very easly.

But, I have found the factory values to work well. In my case, the

values are:


B4 10 10 ALC MIN

B5 20 20 ALC MAX

B6 30 30 ALC.FULL


I have changed this, but I ended up by returning to the same values.

I haven't spent much time tweaking this and I will try it again in the

near future because I am not happy yet with the ALC bar graph



The service manual says that to adjust these values you do this

(supose that we are adjusting B4): connect a 50 ohm dummy load into

your antenna connection. Press [SEND] and the left number will vary

and adjust itseld until it stops varying. Then you can press [UP] and

move the result into the right side. Menu BA will save things.


Now, please notice the following. This 3 menus are hard to tweak and

if you remove the microphone you will get different values.

When, at first, I changed this I tought that this was a "no way back"

setup. After disliking my changes I wanted to go back to the original

values and I strugled to find a way. Here it is: leave the 50 ohm

dummy load on the antenna connection. Remove you microphone. Go to B4.

For this one you want:


B4 10 10 ALC MIN.


Press [SEND] and slowly turn [MIC] until you have 10 on the left side.

This is a tricky adjustment because the number will keep on changing

very quickly. When close to 10 try pressing [SEND] to stop TX and also

to stop the number from changing. You may get a 10 on the left side.

If you went close to 10, try again.

After having 10, just press [UP] and it will go into the right side.


Now, you need 20 for B5:


B5 20 20 ALC MAX


I tryed to get 20 on B5 and I *allways* failed. So I went into B4 and

I got 20 on the left side (same procedure has above). I *did not* press

[UP] because I didn't want to mess up the B4 value.

I used [M.CH/VFO.CH] to change from B4 into B5. Guess what? The 20

value I had on B4 stayed there (on the left side) and went into B5. By

pressing [UP] I updated [B5].


Now, try the same for [B6].


Also, on this menus, I am interested in your results.


B7 - SWR Protection


This item is very important because the value you choose here will

trigger the SWR protection of the rig.

Changing this to a wrong value may cause the SWR protection to work to

late (or not to work at all) and your rig will be transmiting into a

high SWR. The consequences will be serious and you will ruin your

finals (and who knows what else).

So *please* be carefull playing around with this.

Anyway, for the brave of heart, here is the info on how to change this.

>From the factory, mine had this:




Go into B7 and by using [RIT/XIT] you can vary the left number from

00 to FF (256 different levels).

Pressing [UP] will update the right number.

BA menu sabes your changes.


B8 - SWR meter


This will adjust your SWR meter. All 870s that I saw what swr meters

that worked really well, so if your's is working fine leave this menu


If not, try this: you will need a 150 ohm dummy load (yes, not 50 ohm,

but 150 ohm). Hook up the dummy load to the rig. Go to B8 and press

[SEND]. The left number will change. Pressing [UP] updates the right

number and menu BA will save your changes.

*WARNING*: doing this with a 50 ohm dummy load will ruin you swr meter

and will lead you to wrong swr readings (if you use this meter).


B9 - FM Deviation


Factory settings on several 870s seem to be:


B9 80 80 Fm DEV


Going into menu B9 and using the usual [RIT/XIT] button will change

the left number. [UP] will update the right number. BA menu will save

your changes.

To adjust this menu properly you need special test equipment, so I

would advise you to stay away from this one.


BA - System


Refered many times before.





"Ready" means that you can record on the EEPROM.

Pressing [UP] will record *any* and *all* changed menus.

Reply after recording must be:




BB - Display


This will light up all the LCDs and all the leds on the rig.

You can check for a bad LCD or for not working leds.


So, this is it.

You can find more information on this menus on the TS-870S service

manual. Look on page 92 and the following pages.

*I am allways* interested in learning more about this menus (and also

other menus) on the 870.

If you are an Kenwood TS-870S owner and want to change toughts about

your rig fell free to e-mail me at:




I am interested in getting the factory settings of these menus for

different Kenwood TS-870S. If you send your data in, please send also

the serial number of your rig.

Remember that this article may contain incorrect informations (I've

done my best to avoid that from happening). Also the info contained

here can easly get you in trouble.

So remember the golden rule: "if my new setup is wrong I must be able

to go back to the original factory value".

Keeping that in mind myself, I wish you



John, CT2HME