I would think a jammer would not work. I would think that it would most likely have an effect on some of the electronic that would be there to broadcast this live. The better option is for Trump to demand someone check his ear at the start of the debate.
All President Trump has to do, open the debate like this:
Trump - "Hi, I am Donald Trump. What is your name?"
Biden - "I don't know what my name is. Where am I? Who am I?"
.
As others have pointed out, an electronic jammer to stop Joe's handlers talking to the devices they have in Joe's ears, or nose, would be helpful too.
I would think a jammer would not work. I would think that it would most likely have an effect on some of the electronic that would be there to broadcast this live. The better option is for Trump to demand someone check his ear at the start of the debate.