Automatic Band Antenna Switch for Icom (CI-v)


This for people like me forgetting to set a manual switch to the correct antenna.


There were a few designs to be found on the internet but none to what i had in mind, it simply needed to be simple. As the Icom IC7300 is a popular rig and does have some nice technical features i started to look into the band coding and came to the conclusion that the band voltages from the ACC. connector would not do the job for me because 50Mhz and 70 Mhz shared the same output voltage. Looking further at the connectors on the rig the idea of reading the QRG from the Icom was there and started browsing if someone already did this, yes ON7EQ already did most of the work for me, based on his idea and from DM2RM and Werner Rothschopf....... I started my project with the Arduino.


Using a break out board started to place  the arduino and connected the Display and Icom - 7300 using the CI-v remote jack. First had to change the code and make it work for standard I2c 20x4 LCD display so we can use the standard Includes. Werner did change this for what ever reason... but did like the way he did handle the code ( super job !).


As the code only did work for 160 to 6m bands changed some of it to get that work so now also it works for 4m 70 Mhz band. The QRG is now coming from the Icom in MM.KKK.H format ( at later time will work that we also can see the decimal behind the Hz)


The EEprom in Arduino is used to store the selected antenna with the up & down switches and can be reset by holding the 2 buttons and press Reset. When it stores the antenna it will dispay an "m" shortly.


Next did create the PCB in KiCad, you can use up to 8 antenna's but also less, this way you can build to your need. Boards are on order now so will have some available soon.


April 5-2021: Arduino code made available on this page and schematic updated ( relay diodes were wrongly placed)


next i will search or make the housing for it all would say for me that is the most difficult part...


April 29th-2021: Below some pictures of the first build. PCB's are available now ( € 5,- pp), just send an email to( PA2J at and ABASWITCH in the subject line. For those only buying boxes will prepare 4 antenna output completly build units. ( on hold untill new boards arrive in may 2023)


July 25th-2021: added Pictures in "More Pictures"

May 2023: SRD relais new boards ordered ( see picture below)

May 2023: new PCB's arrived


to be continued








Above picture is latest build of June 2021, more pictures will follow as well as setting for IC7300

New version with easier to find SRD relais and better 50 Ohm traces