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.
