"You will notice that the calculator beeps whenever you get close to metal. It beeps even faster the closer you get to the metal. "

This was my first clue that this makes no sense at all. What would possibly induce the calculator to beep in the presence of a metal. Surely it would do so whether it had a radio strapped to its back or not. Never seen one do that yet.

If it worked at all it would have to relate to signal strength received by the radio due to reflection or eddy current losses as the radiated noise approaches the metal. Then maybe there would be a barely audible change. It would be nice if there was some Beat Frequency or Heterodyne effect, but since the radio is not "Tuned" to the calculator's oscillator or any thing like that this is unlikely. This does appear to happen when buttons are pressed as has been mentioned by others, and that is not a surprise.

B.S? I think so.