I have a hunch it can't tolerate outside electromagnetic activity.

A probe would have detected any form of electromagnetic activity.

If there had been less electromagnetic activity in the atmosphere, it would have been easier.

"Well, sir, if what we've got is fierce electromagnetic activity, that could interfere with the signal."

You can therefore map in 3 dimensions electromagnetic activity inside the body by detecting the magnetic field.

The last faint arcing of electromagnetic activity stopped within the brain cells.

They pick up electromagnetic activity in your brain.

Except it was leaking a minute level of electromagnetic activity.

Within a further fraction of a second, all electromagnetic activity from the satellite ceased.