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