Key Radio KME 80 / 150 / 450 Series
Amateur Conversion Information


by Tom Grady G6IGA keyradioatsuperiorsignals.co.uk copyright 1998-2012

All registered trademarks are acknowledged

Key KME Radio


Starting to convert Key KME Radios

Before anything can be set up the first thing that must be configured is the 2764 eprom which holds the frequency information located in the middle of the circuit board

Key KME80 Service Manual in pdf format

Link to Key KME80 Service Manual in pdf format size 45 Megs 63 pages

Programming the frequencies into the 2764 eprom

PLEASE NOTE: I am not able to supply parts, only answer questions about KEY KME series radios ! (I'm always hunting for Key bits myself though)
Hopefully readers of this article will be
familiar with how to actually program a 2764 eprom, the information below purely describes how to calculate the frequency information to go into the 2764. Please contact epromsatsuperiorsignals.co.uk for pre-programmed devices @ 10.90 UK pounds / 13.5 Euros each including 90p postage (Please note most devices I supply MAY be recycled ones). If you supply the blanks then its 5.90 UK pounds / 7.5 Euros each including 90p postage.

KME 80 / 150
The Maths !

In the KME the reference division ratio is defined at the start being either 12.5KHz or 10KHz and cannot be changed per frequency each of the 16 channels must be 12.5KHz or 10KHz steps.
A number of parameters need entered into the Eprom Starting at address 07C0;
The 12.8MHz TCXO is divided by either 1024 to provide a 12.5/25KHz Channel Spacing OR 1280 to provide 20/30KHz Channel Spacing.
12.8MHz/0.0125=1024 or 10000000000 in Binary (put into address 07C0-07CB see table below).
12.8MHz/0.0100=1280 or 10100000000 in Binary (put into address 07C0-07CB see table below).
07CC-07DF Fixed Data for CPU Programming (see table below)
07E0-07FF This area always set to Zero (see table below)
NT Division Ratio (either 1024 or 1280) 1024 = TX Frequency (example 70.4875MHz) / 0.0125 = 5639
To obtain N division ratio and A division ratio NT (5639) = 16 x N (352 x 16) + A (Remainder of 7)
N = Number of Complete Divisions of 16
A = Remainder of the Basic Division Rate
N = 352 or 1100000 in Binary added to channel 1 TX address 0807-0811
A = 7 or 0111 in Binary added to channel 1 TX address 0800-0803
0804-0806 always Zero
0812-081F Always Fixed Data as per table.
NT Division Ratio (either 1024 or 1280) 1024 = RX Frequency (example 70.4875MHz+20.8MHz IF (KME150-20.8MHz IF)) / 0.0125 = 7303
To Obtain N division ratio and A division ratio NT (7303) = 16 x N (456 x 16) + A (Remainder of 7)
N = Number of Complete Divisions of 16
A = Remainder of the Basic Division Rate
N = 456 or 111001000 in Binary added to channel 1 RX address 0827-0831
A = 7 or 0111 in Binary added to channel 1 RX address 0820-0823
0824-0826 Always Zero
0832-083F Always Fixed Data as per table.

Key KME80/150 2764 Eprom Coding
Starts at Address 07C007C007C107C207C307C4 07C507C607C707C807C907CA07CB07CC07CD07CE07CF
Use of AddressN0(1)N1(2)N2(4)N3(8)N4(16) N5(32)N6(64)N7(128)N8(256)N9(512)N10(1024)N11(2048) Fixed for CPUFixed for CPUFixed for CPU Fixed for CPU
1024 12.5/25KHz Channel Spacing (N0-N11)00000 00000100001
1280 20/30KHz Channel Spacing (N0-N11)00000 0001010 0001
Address07D007D107D207D307D4 07D507D607D707D807D907DA07DB07DC07DD07DE07DF
Use Fixed Data for CPU20100 21000200002
Address07E007E107E207E307E4 07E507E607E707E807E907EA07EB07EC07ED07EE07EF
This Area Set to Zero00000 00000000000
Address07F007F107F207F307F4 07F507F607F707F807F907FA07FB07FC07FD07FE07FF
This Area Set to Zero00000 00000000000
Address08000801080208030804 08050806080708080809080A080B080C080D080E080F
Use of AddressA(1)A(2)A(4)A(8)Always 0 Always 0Always 0N(1)N(2)N(4)N(8)N(16) N(32)N(64)N(128)N(256)
Channel 1 TX Data - example 70.4875MHz TX11100 00000001101
Address08100811081208130814 08150816081708180819081A081B081C081D081E081F
Use of AddressN(512)N(1024)Always 1Always 0Always 2 Always 0Always 0Always 0Always 0Always 0Always 0Always 0Always 0Always 0Always 0Always 0
Channel 1 TX Data - example 70.4875MHz TX00102 00000000000
Address08200821082208230824 08250826082708280829082A082B082C082D082E082F
Use of AddressA(1)A(2)A(4)A(8)Always 0 Always 0Always 0N(1)N(2)N(4)N(8)N(16)N(32)N(64)N(128)N(256)
Channel 1 RX Data - example 70.4875MHz (+20.8MHz IF) RX (minus 20.8MHz KME150)11100 00000100111
Address08300831083208330834 08350836083708380839083A083B083C083D083E083F
Use of AddressN(512)N(1024)Always 1Always 0Always 2 Always 0Always 0Always 0Always 0Always 0Always 0Always 0Always 0Always 0Always 0Always 0
Channel 1 RX Data - example 70.4875MHz (+20.8MHz IF) RX (minus 20.8MHz KME150)00102 00000000000
Address0840
Channel 2 TX Data Max 16 Ch



  • Once a programmed eprom has been fitted - alignment of set into a dummy load - should be able to get around 30-35W from the KME80



  • Key KME 80 / 150 Adjustment Points


    KME 450 (420-470MHz)
    The Maths !

    • In the KME the reference division ratio is defined at the start being either 12.5KHz or 10KHz and cannot be changed per frequency each of the 16 channels must be 12.5KHz or 10KHz steps.

    • A number of parameters need entered into the Eprom Starting at address 07C0;

    • The 12.8MHz TCXO is divided by either 1024 to provide a 12.5/25KHz Channel Spacing OR 1280 to provide 20/30KHz Channel Spacing.

    • 12.8MHz/0.0125=1024 or 10000000000 in Binary (put into address 07C0-07CB see table below).

    • 12.8MHz/0.0100=1280 or 10100000000 in Binary (put into address 07C0-07CB see table below).

    • 07CC-07DF Fixed Data for CPU Programming (see table below)

    • 07E0-07FF This area always set to Zero (see table below)

    • NT Division Ratio (either 1024 or 1280) 1024 = TX Frequency (example 434.600MHz) / 0.0125 = 34768

    • To obtain N division ratio and A division ratio NT (34768) = 64 x N (543 x 64) + A (Remainder of 16)

    • N = Number of Complete Divisions of 64

    • A = Remainder of the Basic Division Rate

    • N = 543 or 1000011111 in Binary added to channel 1 TX address 0807-0811

    • A = 16 or 10000 in Binary added to channel 1 TX address 0800-0805

    • 0806 always Zero

    • 0812-081F Always Fixed Data as per table.

    • NT Division Ratio (either 1024 or 1280) 1024 = RX Frequency (example 433.000MHz-45MHz IF) / 0.0125 = 31040

    • To Obtain N division ratio and A division ratio NT (31040) = 64 x N (485 x 64) + A (Remainder of 0)

    • N = Number of Complete Divisions of 64

    • A = Remainder of the Basic Division Rate

    • N = 485 or 111100101 in Binary added to channel 1 RX address 0827-0831

    • A = 0 or 000000 in Binary added to channel 1 RX address 0820-0823

    • 0826 Always Zero

    • 0832-083F Always Fixed Data as per table.


    • Key KME450 2764 Eprom Coding
      Starts at Address 07C007C007C107C207C307C4 07C507C607C707C807C907CA07CB07CC07CD07CE07CF
      Use of AddressN0(1)N1(2)N2(4)N3(8)N4(16) N5(32)N6(64)N7(128)N8(256)N9(512)N10(1024)N11(2048) Fixed for CPUFixed for CPUFixed for CPU Fixed for CPU
      1024 12.5/25KHz Channel Spacing (N0-N11)00000 00000100001
      1280 20/30KHz Channel Spacing (N0-N11)00000 0001010 0001
      Address07D007D107D207D307D4 07D507D607D707D807D907DA07DB07DC07DD07DE07DF
      Use Fixed Data for CPU20100 21000200002
      Address07E007E107E207E307E4 07E507E607E707E807E907EA07EB07EC07ED07EE07EF
      This Area Set to Zero00000 00000000000
      Address07F007F107F207F307F4 07F507F607F707F807F907FA07FB07FC07FD07FE07FF
      This Area Set to Zero00000 00000000000
      Address08000801080208030804 08050806080708080809080A080B080C080D080E080F
      Use of AddressA(1)A(2)A(4)A(8)A(16) A(32)Always 0N(1)N(2)N(4)N(8)N(16) N(32)N(64)N(128)N(256)
      Channel 1 TX Data - example 434.600MHz TX00001 00111110000
      Address08100811081208130814 08150816081708180819081A081B081C081D081E081F
      Use of AddressN(512)N(1024)Always 1Always 0Always 2 Always 0Always 0Always 0Always 0Always 0Always 0Always 0Always 0Always 0Always 0Always 0
      Channel 1 TX Data - example 434.6000MHz TX10102 00000000000
      Address08200821082208230824 08250826082708280829082A082B082C082D082E082F
      Use of AddressA(1)A(2)A(4)A(8)A(16) A(32)Always 0N(1)N(2)N(4)N(8)N(16)N(32)N(64)N(128)N(256)
      Channel 1 RX Data - example 433.000MHz (-45MHz IF) RX11100 00101001111
      Address08300831083208330834 08350836083708380839083A083B083C083D083E083F
      Use of AddressN(512)N(1024)Always 1Always 0Always 2 Always 0Always 0Always 0Always 0Always 0Always 0Always 0Always 0Always 0Always 0Always 0
      Channel 1 RX Data - example 433.000MHz (-45MHz IF) RX00102 00000000000
      Address0840
      Channel 2 TX Data Max 16 Ch


    • Once a programmed eprom has been fitted - alignment of set into a dummy load - should be able to get around 20W from the KME 450 (30W if you change the SO239 Socket for a N-Type Socket !)


    • Key KME 450 Adjustment Points

      Key KME Microphone Wiring

      Key KME Microphone Wiring

      Key KME 32ch Modifications

      • By programming the Eprom so there are two sets of data (or banks) you can switch between the two giving two sets of 16 channels or 32 in total

      • Bank 1 starts at 07C0 and ends at 0BFF (as per instructions shown above)

      • Bank 2 starts at 17C0 and ends at 1BFF (identical format with 2nd set of frequencies)

      • By applying 5v to Pin 2 of the 2764 Eprom (Address Line A12) it switches to Bank 2 (i.e. from lower 4K to upper 4K)

      • 0v at Pin 2 returns it to the original Bank 1

      • By including a 4k7 resistor from Pin 2 to Ground, the set switches the banks cleanly over, without stray voltages holding the set in one or other bank.

      • A simple switch (0v or 5V) on the front panel will alternate between the two banks

      • A convenient 5v supply can be picked up from the rear of the channel switch on the front panel

      • When the banks are switched either power down and up again or transmit for the change over to happen, the switch alone will not change the banks (i.e. refresh from the eprom occurs).

      Key KME 32ch Modifications


      Key KME 32ch Front Panel





      Below is the chart to select the correct CTCSS tone on the CT5 tone board

    CTCSS Tone Chart
    Switch123456
    67.0111111
    71.9011111
    74.4111110
    77.0001111
    79.7111101
    82.5011110
    85.4111100
    88.5001110
    91.5111011
    94.8011101
    97.4111010
    100.0001101
    103.5011100
    107.2001100
    110.9011011
    114.8001011
    118.8011010
    123.0001010
    127.3011001
    131.8001001
    136.5011000
    141.3001000
    146.2010111
    151.4000111
    156.7010110
    162.2000110
    167.9010101
    173.8000101
    179.9010100
    186.2000100
    192.8010011
    203.5000011
    210.7010010
    218.1000010
    225.7010001
    233.6000001
    241.8010000
    250.3000000




    by Tom Grady G6IGA keyradioatsuperiorsignals.co.uk copyright 1998-2012




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