“You just know Biden is going to have an ear piece.”
There are Software Defined Radio (SDR) modules that work with a smartphone or tablet. They can be used as a spectrum analyzer to see the radio signals in the room.
An earbug itself usually works off a magnetic induction loop, at a low frequency, with a loop antenna at the wearers shoulder. That keeps earbug size small. The loop antenna is driven from an RF receiver probably working from 400-600 MHz, depending.
A clever audience member could scan for unusual signals and record them from a smartphone or tablet.
A clever audience member could scan for unusual signals and record them from a smartphone or tablet.
Can hear it now... “Trump campaign announces they have sophisticated electronic eavesdropping devices employed and they will record and publish all communications going to Biden in real-time so the public can see for themselves how Democrats cheat...” :-)
Or, transmit back on the frequency with a stronger signal.
The overriding broadcast goes out at 445 MHz.
"Hey kids. what time is it?"
"It's Howdy Doody time!"
A look of confusion and panic sweeps across Biden's face. Then sudden recognition. He begins to sing, "It's Howdy Doody Time! It's Howdy Doody Time!".