"Pre-pre-compliance" Test Complete

As I mentioned in the last post, PaperMETAR needs FCC compliance testing before I can sell it. After researching what that means for me, I finally feel confident about what’s required.

I can skip full intentional radiator testing and only need unintentional radiator testing because PaperMETAR uses a pre-certified ESP32 module. The goal is to confirm the device won’t interfere with other equipment or radio frequencies. This testing has to be done by a certified compliance lab with the right equipment, and there are plenty to choose from.

I reached out to many labs, and the estimates ranged from $2,700 to $12,000. Part of this range came from differences in testing scope. Some labs even quoted full intentional radiator testing, despite my telling them about the pre-certified module! I’ve since shortlisted a few vendors and am working toward a final pick.

While talking with labs, I also looked into what pre-compliance testing I could do myself. This required a spectrum analyzer. I don’t have access to a full chamber either, so the next best option was to measure emissions in my own environment and look for obvious problems.

I didn’t own a spectrum analyzer, so that was step one. After some research, I settled on the tinySA. It’s a cool tool, and good enough at this stage to rule out glaring mistakes. I’m happy to report that my testing turned up no obvious issues.

Next up is the testing lab, which can run its own pre-compliance test before the final one. I hope to choose a lab this week and ship the prototype unit right after.