I built an iOS app for myself: a set of RF calculators (inductance and reactance, toroids, air core inductors, parallel/series resistors and capacitors, pi networks, etc). Using Ionic framework and Codex, it took only a few hours to have something decent enough that I'll use it for myself. I previously had a web page I had collected calculators on, but this is on the phone all the time. We'll see how it goes, but pretty happy with it so far. #HamRadio #AmateurRadio