icom decoder board image


Contact me if you are interested

The board includes two band decoders using 4 bit BCD from your radio or logging program. The board can be power directly with 12V DC or 18V P-P AC fed to the rectifier section. I laid the board out such that you can just add the components for the simple version of the controller, if you don’t need the band decoders for example. The band decode segment includes an option to lockout antenna switching while transmitting. If you do not need the PTT controlled lockout you can leave that segment out as well. These sections are clearly marked on the PC board and in the assembly documentation.

  • Dimensions: 1.8″ x 1.3″
  • NTE1508 Dot/Bar Driver is difficult to find – required part
  • High quality FR4 double sided 1oz copper, masked, and silk screened both sides.
  • A fully opto-isolated interface between an Icom radios analog voltage band data output and the Antenna Switch Controller
  • Designed as a “daughter card” which plugs into the CD4028 socket of one or the other port of the controller
  • Takes the place of all the components of one of the two decoders
  • Can be used as a stand-alone decoder as well!
  • Discrete pin in hole component design – you might have many of the components in your junk box!

Construction Details

Illustrated assembly details and parts list

Mouser Parts List

Brings you to Mouser.com with a full parts list to edit

Schematic Diagram

Circuit details

Please note: All electronic parts are included in the project file. Any unneeded part can easily be removed from the Mouser order. There are “optional” parts included in the list PLEASE PAY ATTENTION FOR THESE. If you have questions please reach out to me.

Looking for more info or ideas…

Check out the FAQ link in the header or the twisties below

Icom Decoder Daughter Card Parts List

These parts are available in the Mouser Project File link, and are easily available to edit and put into your Mouser shopping cart. I have no affiliation with Mouser, but just that it is super easy and convenient. Get the parts however you would like!

Relay Control Section – This is all you need to build if you are going fully manual:

  • 1 – Diode 1N4148
  • 3 – 0.01uF ceramic capacitor
  • 3 – 220uH radial inductor
  • 2 – 1kΩ 1/8W 1% Resistor
  • 1 – 8.2kΩ 1/8W 1% Resistor
  • 1 – 10kΩ 1/8W Resistor
  • 1 – LM3415 or NTE1508 Dot/Bar Driver DIFFICULT TO FIND
  • 1 – 2N3906 PNP transistor
  • 2 – PS2501-4 4Ch opto-isolator
    (if you already build the decoder on the controller board you don’t need these)
  • 3 – 16pin DIP socket
  • 1 – 18pin DIP socket
  • 2 – 9 position header 100mil pitch
  • 1 – each optional pad resistors 604Ω, 806Ω, 1.2kΩ, 1.4kΩ
Lots of band pass filtering ideas and options
KK1L station configuration in the 2010’s