In retrospect this seems obvious, but after trying to pre-set FM stations on the clip, I realized that the use of FM Radio is possible ONLY with the headset plugged in. Most likely it’s the headset functions as antenna. If this helps even one person struggling with getting the FM Radio to work, it was worth posting. If everybody but me already figured this out, then smile and move on.
Yeah, it uses the headphones as the antennea.