Somebody mentioned that, if it was working as presented, it was probably acting like an antennae and picking up energy from other sources, like a nearby lamp
Lamps don’t emit rf. Rf is the full spectrum of radio signals such as for tv, radio, cb, shortwave, etc. low power but ever present, ready to be amplified.
Radio shack used to sell a simple kit for a radio that was powered in the same fashion. Just used a solenoid with thousands of turns around a ferromagnet.
Tvs and radios generally plug into the wall so don’t require as strong a solenoid to amplify the signal by induction.