ICOM Transceivers

Some details are on this page on what was done to change an IC-22A and IC-22S and IC-30A to operate with a DDS. The DDS provides frequency selection by rotary encoder, repeater offset, memory storage and scanning. Downloads are provided for the circuit diagram and the code for the Arduino Micro used.

IC-22A before and after - uses an AD9850

IC-22S before and after - uses a Si5351

Front Panel

The front panel was made from the top of a HB6015 Jiffy Box available from Jaycar. The layout plan is a sketch and not to scale - dimensions need to be checked with the transceiver. I used a small router from AliExpress to cut the slot for the display but there are other ways to do that. Care is needed to drill the hole to mount the rotary switch on the transceiver. The rotary encoder is mounted on the plastic panel.

Download circuit and code as zip folder

Do note that the solution is not perfect. The Arduino does have some spurious signals - 147600 and 146400 are particularly impacted on receive. Not likely to be much bother for most and it is still a heap better to be able to select operation anywhere on the band.  
Note also to remove any capacitor between the base and emitter of the existing XTAL oscillator in the IC-22A and the IC-30A - we want that to now serve as an amplifier.  

Download circuit and code for the IC-30A

Like the IC-22 note that the solution is not perfect and has some spurious signals on receive. The physical layout and construction is the same as shown for the IC-22 transceivers but the circuit and code is different which is available in the download below.