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TUCoPS :: Radio :: ic22a.txt

Icom IC22S Packet Modification

                 Icom IC22S Packet Modification
      The Icom IC22S is a ten watt diode matrix PLL synthesized
     2 meter rig manufactured in the early 1970's. In it's stock
     condition it tunes 146-148 MHz in 15 KHz steps. Since I am
     sure there are a few of these sitting on shelves collecting
     dust due to the limited tuning range, why not modify them
     for the perfect packet rig.
      First replace the 7.68 MHz Oscillator/Divider crystal (X1)
     with a 5.12 MHz crystal. This will move the band to 145.00-
     146.94 MHz in 10 KHz increments. The repeater offset will
     now be 400 KHz which should not pose a problem in simplex
     packet operation. I will give the diode matrix settings for
     the most commonly used packet frequencies. You can formulate
     others as needed using the formula N=100*(f-145)+61 and the
     manual. The diode positions indicated ARE WHERE DIODES ARE
     PRESENT. The other positions are left empty.

             145.01= D5,D4,D3,D2,D1
             145.03= D6
             145.05= D6,D1
             145.07= D6,D2
             145.09= D6,D2,D1

      73's de Scott N5JLQ @ K6IYK 

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