so ive been messing around with this idea for a while and finally started actually building it. basically i want to use an arduino mega to handle all my antenna switching automatically based on what band the radio is on. i have an IC-7300 and it puts out band data on the USB port so im thinking i can just read that and use relays to switch between my dipole, the vertical, and the 6m yagi.

started prototyping on a breadboard last night and the relay logic seems to work fine but im not sure the best way to handle the reed relays vs just regular 5v relays for RF. the RF path itself wont go through the arduino obviously, just the control lines, but still want to make sure im not doing something dumb with the grounding. anyone done something similar? also wondering if a raspberry pi zero would be overkill for this or if theres an advantage to having linux on there instead of bare metal arduino.

the IC-7300 CI-V stuff over USB is pretty well documented so thats not the concern, more the hardware side of things honestly

yeah done almost exactly this with a 7300 and an uno a couple years back. the CI-V decoding is pretty straightforward once you get the baud rate sorted, there's libraries that handle most of the heavy lifting. for the relays i just used a cheap 8-channel 5v relay board from amazon, nothing fancy, and it's been rock solid. the RF doesnt go anywhere near the arduino like you said so interference hasnt been a problem. one thing i did learn the hard way — put a flyback diode across each relay coil if you're driving them directly from arduino pins, found that out after i fried a pin on my first uno. the relay boards usually have them built in but worth checking.

as for pi zero vs arduino, honestly for just switching i think the arduino is the right call. simpler, boots instantly, doesnt need an OS to babysit. i use a pi 4 for logging and rig control software but the switching is all arduino. keeps things modular too if something breaks

pi zero is probably overkill for relay switching yeah but if you ever want to add a web interface to control things remotely or log switch events it starts making more sense. i run a pi zero W for my rotor controller and being able to just pull up a webpage on my phone is pretty handy. that said the latency when it boots is annoying and if power goes out you gotta be careful with the SD card corruption thing — learned that one the hard way a few times.