Joseph Lorenzo Hall, PhD on Nostr: The clock's internal ferrite rod antenna is deaf to the loud 20 kHz audio but ...

The clock's internal ferrite rod antenna is deaf to the loud 20 kHz audio but perfectly resonates with the faint 60 kHz magnetic pulse. Because it relies on near-field magnetic induction, the phone must be very close the clock to overcome the rapid cubic signal drop-off. 3/4