

                       
                        KENWOOD TH-79
                     ~~~~~~~~~~~~~~~~~~
                          INFO FILE

CHANGING THE BANDS:
===================
Press the F-key andthen press the LOW-button to toggle between Air-Band
(340Mhz on the VHF Band) or the Phone-Band (850Mhz on the UHF band) and
the amateur radio band.

CROSBAND-REPEATER:
==================
  The TH-79 does go into X-Band repeat.  Press the "F" key then the "MONI"
key to enter repeat mode.  Use the same to return to normal.  There is a 
10 min transmit limit so it's not useable for long duration monitoring of
a continuous transmission.  That's understandable in light of the number 
of horror stories I've heard of people frying their HT's in repeat mode.

CLONING THE TH79E
=================
To clone the memory contense of two radios on the air. The clone procedure
is same with all others. ( use of DTMF tones, do not disturb transmission
etc.) You must take care that both radios are really same: both have
extended range or not, both are E-version or not etc.
It will cause some problems if you try to clone i.e. an E version
without expansion into a A- or J version.
If you have both radios please hold down the -0- key / PAG L Key when
you switch on the radio. So you see the letters CLONE on the display.
Please push the ptt on the radio which has to be the master.
It takes a time to transmit all memory with maybe names, call sign etc.
After Clone is finished you see END written in Display. Best is to switch
of both radios. After switching on again you will have two same radios !

EXTENDED RX/TX
===============
Thats all...Don't  cut the green wire, or install any jumpers as before.
This mod is the official one from Kenwood, taken from a data sheet put out by
them.
1. Open the unit by removing three screws from the back and one under the
   DC power input cover.  Carefully separate the front and back pieces.
   The two case halves may be disconnected by pulling the wired plug and by
   prying the brown latch on the ribbon cable connector up enough to
   release it.
2. On the front PC board in the lower right corner as viewed from the rear
   with the knobs pointing up there are seven spots for diodes in a row,
   with one diode missing.
                          | o o o o x o o  |
                           ________________|
                            2 3 4 5 6 7 8
   The numbers are D302-D308, left to right, with D306 missing.
3. Remove diodes D304 and D307.
   Now you must have this:
                          | o o x o x x o  |
                           ________________|
                            2 3 4 5 6 7 8
5. Reassemble and apply power.  Mod complete.
Now the ranges:
   67-174.995 and 400-511.995 RX
  136-174.995 and 400-511.995 TX.

PS:  Just cutting the green wire by the recharging jack is the 
MARS mod.. Don't cut if you intend to do the above mod..

Discription of the diodes:
==========================
In my HT diode D303 are not installed, green wire cut. RX as wide as
possible (69-179Mhz) and TX from about 130 to 179 MHZ. No crossband repeater.
Now I tried to modify the handy, but i was not carefuly.
I removed D305 and the Bander goes in the Lock-key modus:
  All keys are locked in cases of the Lock-switch.
  QRG disapeared and the channel nummbers shine on the display.
Then I put D307 to the place I removed D305:
  Now I had the TH79A version with no light, but a call channel installed.
  All functions are the same as before, but TX was only possible on the
  amateur radio bands. Automatic shift keying as discriped in the manual
  for the american version. (Not to usefull in Europe :-), but you can
  change the QRG's now....)
Not the situation on the TH79A I wand, I remount diode D306 to the location
of diode D307 to change to TH79E back. And now the work was finished:
  Transmitting as descriped above, no lock function activ, crossband repeater
  enabled. THE MENU-SETTING 18 are activ: "Answer back function" for the
  paging mode: transmitts an code back to show tha the call received.
  But the continues TRX showing up later in this doc has not been verifyed.
The purpose of diode D302 was not to be able to find out because the first
diode I wand to unmount had been damaged ;-(

Here is the MARS/CAP modification
=================================
1. Remove battery.
2. Open case by first removing 3 screws (#00 Phillips) on back and 1 screw 
   on side hidden underneath the rubber flap covering the DC power jack. 
   Gently pry apart starting at top; BNC connector will move with back, 
   knobs with front.
3. Spread unit out. Wires will "hinge" on the side with the PTT button.
4. Looking on the back of the keypad (front) half, locate green wire on 
   upper left, just below the CTCSS decoder module.
5. Neatly cut this green wire, and tuck back in so ends won't touch each 
   other or other components.
6. Reassemble.
   Programmed memory will be lost since the CPU will notice the strap change 
   and reset itself.
  
   Before: VHF RX - 118.000-173.995  TX - 144.000-147.995         
           UHF RX - 438.000-449.995  TX - 438.000-449.995
   After:  VHF RX - 118.000-173.995  TX - 142.000-151.995
           UHF RX - 420.000-449.995  TX - 420.000-449.995

If I read the schematic right, the green wire corresponds to "W301", which
also serves the same purpose as removing "D308". More research needs to be
done on other mods; I'm especially interested in extending UHF receive beyond
450. There is a row of diodes right below the uC which appear to be D302 

Remote Base Operation with Kenwood 732/733
==========================================
Kenwood has now simplified remote base operation of their mobile rigs
with the TH79.

I will not give a step by step on how to control the mobile rigs, since
they are different. Hoewever, to really understand this feature, I would
first get to know the remote control feature on the mobile very well. This
makes the following explanation a little clearer!

To access this feature, hold [PTT] and [MR] while [POWER ON].

The display will indicate -RC-, which I presume means 'Remote Control'.

If you have correctly matched your DTSS codes, frequencies, etc, the
dual bander's keypad now becomes a function pad. Pressing certain keys
enables or disables functions on the mobile rig by sending the DTMF
sequences for you.

Please note that all this fuction does is send the DTMF tones over the air
to control your mobile rig. I have not made a list of what each key does,
but as the 79 sends the DTMF tones, the display will indicate the function.
(i.e. - RPT ON, RPT OFF, TONE ON, TONE OFF, etc.)

"The "RC" function is configured to directly control radios such as
the TM-732.  In fact, if you look at the layout of the microphone remote
commands for the 732 it very closely matches the key assignments for of
the "RC" mode.  Since I have a TM-732 installed in my car, I had a chance
to try this out and it's VERY convenient.  Everything from direct frequency
entry with the "F" key to enabling X-Band repeat.  I'm really surprised 
they aren't marketing this feature of the radio."


Measured specifictions of TH79
==============================

Band - VHF -----------------------------------------------------
Frequency       Sens (uV)       Power           Mode
---------       ---------       -----           ----
108             4               -               A3
110             2               -               "
115             .75             -               "
120             .40             -               "
125             .30             -               "
130             .30             -               "
135             .30             -               "
140             .12             2.9             F3
145             .12             2.9             "
150             .13             2.8             "
155             .15             2.4             "
160             .18             1.9             "
165             .20             1.45            "
170             .21             1.10            "
175             .30             0.85            "
179.995         .35             0.70            "

 
Band - VHF (2) (set to 300Mhz) --------------------------------
Frequency       Sens (uV)       Power           Mode
---------       ---------       -----           ----
300             50/75           -               A3/F3
320             4/20            -                 "
340             .3/.6           -                 "
360             .2/.5           -                 "
380             .2/.6           -                 "
400             .2/.75          -                 "


Band - UHF -----------------------------------------------------
Frequency       Sens (uV)       Power           Mode
---------       ---------       -----           ----
400             11              1.0             F3
410             4               1.5             "
420             1               1.85            "
430             .2              2.2             "
435             .12             2.3             "
440             .10             2.5             "
445             .10             2.5             "
450             .10             2.5             "
455             .15             2.3             "
460             .16             2.3             "
465             .20             2.0             "
470             .45             1.8             "
480             1               1.6             "
490             2               1.3             "
500             6               1.1             "
510             no RX over 509  0.8             "

  BTW, close inspection of the RF deck in my radio shows no obvious
missing parts.  I didn't remove the board to check the other side, but
my suspicion is that the 800 MHz parts are installed.  I'd be interested
in input from others on that.  So far I've not discovered how to make it
display any 800 MHz frequencies though."

CONTINOUS TRX
=============
Pressing the VFO-key and the PTT key after a short beep and waiting a few
seconds with these two keys pressed will bring the th-79e into continous
transmit mode for about 10 minutes until TOT ends.
This will also work with the MR key.

Near the allodgment of TSU8 there is a green wire: cut it.
1 centimeter up there is a resistance of 0 ohm!!:remove it.
So you can receive the 300 mhz band and the 900 mhz band
(you can find now this function in the menu 20 and 21).
To receive these frequences go in vfo mode and press F and
then key "low/hi/lo/el";if you are in vhf vfo you receive 
from 300 to 399;if you are in uhf mode you receive from 800 to 999 
You have the function of transponder too.
To active this function go in dual mode(uhf-vhf)and press F
and then the "moni" key.
That's all for the moment,i hope you enjoy it.
I'll send you other modifies if i'll receive something.


end of TXT file

ͻ
  KB2LJJ BBS  RADIO MODS BATABASE     All the MODS are captured by packet.
ͻ       ͼ   This BBS takes no responsability or
ͼ       ͻ   liability for any damege resulting
     KB2LJJ @ KB2LJJ.NJ.USA.NA        from this modification.
ͼ   73s John kb2ljj SySoP
