Icom Ic-22s question/problem

[KF5PGT]

I recently picked up an Icom Ic-22s mobile rig in a package deal. I have the manual, but I can't seem to figure out how the channels work on this thing! I cracked it open and see where the diode matrix is, and it seems like the previous owner added afew channels. I've figured out what channels those are on, as well as a few other frequencies.

Here's where I get lost. It seems like the previous owner changed the dial, or at least the channel indicator. The channel indicator goes from 601 to 796 in six step intervals when the orginal dial went to 22 or 23. The dial and the manual don't sync up. The channels seem to jump around. For instance, 700-724 is 146.160-146.435 but 670 is 146.520.

Anyone know anything about this mod? Anyone have any ideas on how to figure out what channel is what?

[W9GB]

Marx -

I owned the Icom IC-22S, when they were new in mid-1970s.
It shares many case parts with the IC-22A, which was a 22 channel crystal controlled radio.

The factory version of the IC-22S used a 23 position knob, which was numbered 1-22 with the 23rd blank, as I remember. The frequencies for each of these channel positions was programmed (diode matrix) with 1N914/1N4148 silicon high-speed diodes.

Now, digital technology was progressing rapidly in this time period -- and a number of third-party modification kits (in USA) were offered to expand upon or change how this diode matrix scheme worked.

Some of these kits changed the channel switch and indicator to more than 23 positions.
These switches, 23 and 40 position, were very cheap in late 1970s -- due to end of 1970s CB craze and large parts surplus.
http://www.k9ya.org/w9bb/ic-22s_mods.htm

There were several -- you would have to read the magazines advertisements of that period -- to see all the different versions or try to find out what you have, IF no documentation was provided by former owner.

[KF5PGT]

Unfortunately, this rig's previous owner is a SK and I have no donumentation. The 60 channel synth mod in that link seems to be what mine has. If I count a full rotation of the dial, it's 60 steps.

Now I'm getting somewhere! Thanks for the help!

[K0RGR]

My ham family all had 22Ss at one time - four of them. I put some of those modes in myself. I vaguely recall adding thumbwheel hex switches that could be used to dial up all of the possible diode combinations for the different frequencies. It was awkward, but you could work all of the 2 meter repeaters in at least part of the band (not sure if it worked below 146 or below 145). You had to have a list so you could convert the hex number to the frequency. I also think there was a +5 kHz switch involved somewhere.

[WA7KKP]

Sounds like it has the VIP switch, but it should read out correctly if it did. Maybe someone hacked in a switch with some sort of dial.

Keep in mind that Dup A is transmitter down 600 kHz -- Dup B moves the RECEIVER down 600 kHz. "Upside down" repeater users have to keep that in mind when programming the radio.

You best get the book and go from there.

Gary WA7KKP