Modifications for the Kenwood TH-48

Secret function manual of the KENWOOD TH-28e/48e porto


TH-28e/48e RX EXPANSION (ON)

Press PTT + VFO, then POWER ON.
New RX ranges TH28e after this modification:
VHF Band 136 - 174 Mhz (FM)
UHF Band 400 - 520 Mhz (FM)

TH48e:
UHF Band 400 - 470 Mhz (FM)
VHF Band 136 - 174 Mhz (FM)

TH28e Air Band Expansion

Press F key for 1 sec. Then press LOW key.
New RX ranges
108 - 118 Mhz (FM)
118 - 136 Mhz (AM)
TH28e 340 - 400 Mhz Expansion
Remove the diode D8 from the control unit. (FM mode only) With Air Band and 340 Mhz expansion, operating band can be changed:
           _________      _________      __________
     ---->I AMATEUR I====I 340 Mhz I--->I AIR BAND I_____
     I    I_________I    I_________I    I__________I     I
     I___________________________________________________I
TH48e 340 MHZ & 900 MHZ EXPANSION

Remove the diode D8 from the control unit to cover 340 - 400 Mhz and 800 - 950 Mhz FM mode.
           _________      _________      _________
      --->I AMATEUR I--->I 340 Mhz I--->I 900 Mhz I_____
     I    I_________I    I_________I    I_________I     I
     I__________________________________________________I
TH-28e/48e TX EXPANSION

Remove the diode D10 from the control unit.
New TX ranges after this modification:

TH28e:
VHF Band 136.000 - 174.250 Mhz (FM)
TH48e:
UHF Band 400.000 - 470.000 Mhz (FM)

Note:
Manufacturer guarantees TX/RX specification only in amateur band. The above frequency range is for the microprocessor's range so that the receiver sensitivity or TX output power of expanded band may be reduced.

TH-48E TX/RX 432-438 Mhz LIMITED RANGE

Remove the diode D14 from the control unit.

TH28e/48e CROSS BAND REPEATER

Remove the diode D4 then press F key for 1 sec. and press 0 key.

TH-28a/e-48a/e FREQUENCY EXTENSION

Open the case and remove or add the destination chip diode D10, D11, D14 and D15 on the component side of the control unit.
(X53-340X-XX, X53-341X-XX)
The frequncy can then be extended as shown in the table 1 an 2 on page 3 and 4.(See the destination chip diode position drawing on the attached sheet.)

Notes:
The frequency display range may differ from the PLL lock range.

  ___________________________________________________________________
 I                   I       360-Mhz band    I        Air band       I
 I===================I=======================I=======================I
 I        Step       I5,10,15,20,12.5,25 Khz I5,10,15,20,12.5,25 Khz I
 I-------------------I-----------------------I-----------------------I
 I  Frequency range  I340.000-399.987.5 Mhz  I 100.000 - 117.975 Mhz I
 I                   I          FM           I          FM           I
 I                   I                       I 118.000 - 135.995 Mhz I
 I                   I                       I          AM           I
 I-------------------I-----------------------I-----------------------I
 I Initial frequency I       340.000 Mhz     I      118.000 Mhz      I
 I___________________I_______________________I_______________________I

Initial step value is 12.5 Khz for 360-Mhz band and 25 Khz for Air band.
TH-48a/e BAND EXTENSION

The 360 Mhz band and the 800 Mhz band can be received. To expand the 360-Mhz band and the 800-Mhz band remove chip diode D8 of the control unit as shown in table 2.
You can switch between the UHF amateur band the 360-Mhz band and the 800-Mhz band by pressing the [ F ] key for 1 sec. and then the [ LOW ] key.
  ___________________________________________________________________
 I                   I      360-Mhz band     I     800-Mhz band      I
 I===================I=======================I=======================I
 I        Step       I5,10,15,20,12.5,25 Khz I      12.5,25 Khz      I
 I-------------------I-----------------------I-----------------------I
 I  Frequency range  I 340.000-399.987.5 Mhz I 800.000-949.987.5 Mhz I
 I                   I          FM           I          FM           I
 I-------------------I-----------------------I-----------------------I
 I Initial frequency I       340.000 Mhz     I      850.000 Mhz      I
 I___________________I_______________________I_______________________I
Note:
Program scan is not possible over several bands, but is possible within each band.
Initial step value is 12.5 Khz.

Table 1 TH28a/e
 __________________________________________________________________
I    Destination bit     I    IGuaranteed I  TX (Mhz) I  RX (Mhz) I 
I________________________IDestI___________I___________I___________I
I B4 I B3 I B2 I B1 I B0 I    I Min I Max I Min I Max I Min I Max I
I----I----I----I----I----I----I-----I-----I-----I-----I-----I-----I
I  O I  O I  O I  X I  O I E2 I 144 I 146 I 136 I 174 I 136 I 174 I
I----I----I----I----I----I----I-----I-----I-----I-----I-----I-----I
I  O I  O I  O I  X I  X I E2 I 144 I 146 I 136 I 174 I 136 I 174 I 
I----I----I----I----I----I----I-----I-----I-----I-----I-----I-----I
I  O I  X I  O I  X I  O I M2 I 144 I 148 I 136 I 174 I 136 I 174 I
I----I----I----I----I----I----I-----I-----I-----I-----I-----I-----I
I  O I  X I  O I  X I  X I M2 I 144 I 148 I 136 I 174 I 136 I 174 I
I----I----I----I----I----I----I-----I-----I-----I-----I-----I-----I
I  X I  O I  O I  X I  O I X2 I 144 I 148 I 136 I 174 I 136 I 174 I
I----I----I----I----I----I----I-----I-----I-----I-----I-----I-----I
I  X I  O I  O I  X I  X I X2 I 144 I 148 I 136 I 174 I 136 I 174 I
I----I----I----I----I----I----I-----I-----I-----I-----I-----I-----I
I  X I  O I  X I  X I  O I K2 I 144 I 148 I 142 I 152 I 136 I 174 I
I----I----I----I----I----I----I-----I-----I-----I-----I-----I-----I
I  X I  O I  X I  X I  X I K2 I 144 I 148 I 142 I 152 I 136 I 174 I
I____I____I____I____I____I____I_____I_____I_____I_____I_____I_____I
 D15  D11  D14  D10  D8                                           :
   O = Jumpered   X = No jumper                                   :
......<............<.............<.............<.............<....:

:                                                       ____________
:                                                      I  Sub-UHF
:______________________________________________________I____________
I Reset I Offset I Shift I Auto I 1750 I  Air  I  360  I RX (Mhz)  I
I freq- I  freq- I freq- I shiftI tone I band  I band  I-----------I
I       I        I       I      I      I       I       I Min I Max I
I-------I--------I-------I------I------I-------I-------I-----I-----I
I  144  I  0.6   I  12.5 I  O   I   O  I   O   I       I 400 I 520 I
I-------I--------I-------I------I------I-------I-------I-----I-----I
I  144  I  0.6   I  12.5 I  O   I   O  I   O   I   O   I 400 I 520 I
I-------I--------I-------I------I------I-------I-------I-----I-----I
I  144  I  0.6   I  12.5 I      I      I   O   I       I 400 I 520 I
I-------I--------I-------I------I------I-------I-------I-----I-----I
I  144  I  0.6   I  12.5 I      I      I   O   I   O   I 400 I 520 I
I-------I--------I-------I------I------I-------I-------I-----I-----I
I  144  I  0.6   I   5   I  O   I      I   O   I       I 400 I 520 I
I-------I--------I-------I------I------I-------I-------I-----I-----I
I  144  I  0.6   I   5   I  O   I      I   O   I   O   I 400 I 520 I
I-------I--------I-------I------I------I-------I-------I-----I-----I
I  144  I  0.6   I   5   I  O   I      I   O   I       I 438 I 450 I
I-------I--------I-------I------I------I-------I-------I-----I-----I
I  144  I  0.6   I   5   I  O   I      I   O   I   O   I 400 I 520 I
I_______I________I_______I______I______I_______I_______I_____I_____I
                                                                   :
                                                                   :
......<............<.............<.............<.............<.....:
:
:______________
    Sub-UHF    I
 ______________I
I Reset I Step I      .......>.....I-------I------I
I freq. I freq.I      :            I  430  I  25  I 
I       I      I      :            I-------I------I 
I-------I------I      :            I  430  I  25  I 
I  430  I  25  I      :            I-------I------I 
I-------I------I      :            I  440  I  25  I
I  430  I  25  I      :            I-------I------I 
I-------I------I      :            I  440  I  25  I
I  400  I  25  I      :            I_______I______I
I-------I------I      :
I  400  I  25  I      :               
I-------I------I....>.:
Table 2 TH48a/e
 __________________________________________________________________
I    Destination bit     I    IGuaranteed I  TX (Mhz) I  RX (Mhz) I 
I________________________IDestI___________I___________I___________I
I B4 I B3 I B2 I B1 I B0 I    I Min I Max I Min I Max I Min I Max I
I----I----I----I----I----I----I-----I-----I-----I-----I-----I-----I
I  O I  O I  X I  O I  O I E3 I 430 I 440 I 400 I 470 I 400 I 470 I
I----I----I----I----I----I----I-----I-----I-----I-----I-----I-----I
I  O I  O I  X I  O I  X I E3 I 430 I 440 I 400 I 470 I 400 I 470 I 
I----I----I----I----I----I----I-----I-----I-----I-----I-----I-----I
I  O I  X I  O I  X I  O I M2 I 430 I 440 I 400 I 470 I 400 I 470 I
I----I----I----I----I----I----I-----I-----I-----I-----I-----I-----I
I  O I  X I  O I  X I  X I M2 I 430 I 440 I 400 I 470 I 400 I 470 I
I----I----I----I----I----I----I-----I-----I-----I-----I-----I-----I
I  X I  O I  O I  X I  O I X2 I 430 I 440 I 400 I 470 I 400 I 470 I
I----I----I----I----I----I----I-----I-----I-----I-----I-----I-----I
I  X I  O I  O I  X I  X I X2 I 430 I 440 I 400 I 470 I 400 I 470 I
I----I----I----I----I----I----I-----I-----I-----I-----I-----I-----I
I  X I  O I  X I  X I  O I K2 I 438 I 450 I 400 I 470 I 400 I 470 I
I----I----I----I----I----I----I-----I-----I-----I-----I-----I-----I
I  X I  O I  X I  X I  X I K2 I 438 I 450 I 400 I 470 I 400 I 470 I
I____I____I____I____I____I____I_____I_____I_____I_____I_____I_____I
 D15  D11  D14  D10  D8                                           :
   O = Jumpered   X = No jumper                                   :
......<............<.............<.............<.............<....:

:                                                       ____________
:                                                      I  Sub-VHF
:______________________________________________________I____________
I Reset I Offset I Shift I Auto I 1750 I  360  I  800  I RX (Mhz)  I
I freq- I  freq- I freq- I shiftI tone I band  I band  I-----------I
I       I        I       I      I      I       I       I Min I Max I
I-------I--------I-------I------I------I-------I-------I-----I-----I
I  430  I   *    I   25  I      I   O  I       I       I 136 I 174 I
I-------I--------I-------I------I------I-------I-------I-----I-----I
I  430  I   *    I   25  I      I   O  I   O   I   O   I 136 I 174 I
I-------I--------I-------I------I------I-------I-------I-----I-----I
I  430  I   5    I   25  I      I      I       I       I 136 I 174 I
I-------I--------I-------I------I------I-------I-------I-----I-----I
I  430  I   5    I   25  I      I      I   O   I   O   I 136 I 174 I
I-------I--------I-------I------I------I-------I-------I-----I-----I
I  430  I   5    I   25  I      I      I       I       I 136 I 174 I
I-------I--------I-------I------I------I-------I-------I-----I-----I
I  430  I   5    I   25  I      I      I   O   I   O   I 136 I 174 I
I-------I--------I-------I------I------I-------I-------I-----I-----I
I  440  I   5    I   25  I      I      I       I       I 136 I 174 I
I-------I--------I-------I------I------I-------I-------I-----I-----I
I  440  I   5    I   25  I      I      I   O   I   O   I 136 I 174 I
I_______I________I_______I______I______I_______I_______I_____I_____I
         * = 1.6M, -7.6M                                           :
                                                                   :
......<............<.............<.............<.............<.....:
:
:______________
    Sub-UHF    I
 ______________I
I Reset I Step I      .......>.....I-------I------I
I freq. I freq.I      :            I  144  I   5  I 
I       I      I      :            I-------I------I 
I-------I------I      :            I  144  I   5  I 
I  144  I 12.5 I      :            I-------I------I 
I-------I------I      :            I  144  I   5  I
I  144  I 12.5 I      :            I-------I------I 
I-------I------I      :            I  144  I   5  I
I  136  I 12.5 I      :            I_______I______I
I-------I------I      :
I  136  I 12.5 I      :               
I-------I------I....>.:
CLONING THE RADIO

  1. Overview of the clone function. (The function does not require frequency expansion.)
    Since 240 channels are available if an option is installed, it is laborious to write the same memory channel frequency data into several transceivers. Once you write data into one transceiver, you can duplicate it in several others in a single operation with the clone function. (You can write data without installing an option.)
  2. How to use the clone function.

    Transmitter setup:
    1. Write the required memory channel frequency data into the transceiver.
    2. Set the transmit frequency.
    3. Switch the power off, hold down the 7 key on an F series tranceiver or the MR and PTT keys on a K series, and switch the power on again.
    "CLONE" appears on the display.
    (The transmit output is automatically set to "economic low".)

    Receiver setup:
    1. Set the frequency of the transceiver to the transmit frequency of the transmitter.
    2. Switch the power off, hold down the 7 key on an F series transceiver or the MR and PTT keys on a K series one, and switch the power on again.
    "CLONE" appears on the display.
    Press the PTT key on the transmitter. The clone function works automatically. When cloning ends, the frequency is displayed again.
    It takes about four minutes to transfer frequency data for 40 channels, and about nine minutes to transfer frequency data for 240 channels.
    If the receiver is an F series one and the frequency is displayed again, switch the power off, hold down the F key, and switch the power on again (VFO reset). If the receiver is a K series one and the frequency is displayed again, switch the power off and on again.
    Thus, cloning lets you copy the channel data stored in the transmitter to other transceivers in a single operation. To stop cloning, switch the power off and on again. 
 __________________________________
I                                  I
I          Control Unit            I        Bit 0.....D8   (MA110)
I                                  I        Bit 1.....D10  (MA110)
I     TH28a/e : X53-340X-XX        I        Bit 2.....D14  (MA110)
I     TH48a/e : X53-341X-XX        I        Bit 3.....D11  (MA110)
I                                  I        Bit 4.....D15  (MA110)
I                                  I
I                                  I
I                                  I
I                                  I
I                                  I
I   D15     D14                    I
I      \_ _/                       I
I      I I I                       I
I      I_I_I       D10 D8          I
I              _ _/  _/            I
I         D11-I I I I I            I
I             I_I_I I_I            I
I__________________________________I

I                                  I
I          Control Unit            I
I          X53-3420-00 A/5         I
I                                  I
I      .............               I
I      :           :               I
I      :    CPU    :  ___          I
I      :           : I___I D1      I
I      :           : I___I D2      I
I      :...........: I___I D3      I
I                    I___I D4      I
I                    I___I D5      I
I                    I___I D6      I
I                                  I
I__________________________________I

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