# Forms of Magnetic Noise Coupling

I was watching a video of Bob Pease discuss magnetic coupling of noise into the ground lead of an oscilloscope probe. See video at 5:40 https://www.youtube.com/watch?v=2vzvWUqUtb8

I noticed another person at the table say "you really need to worry about that when you do switchers because the noise comes in through the leads." "it acts like an antenna."

I don't understand what he is describing. So I started thinking...

1. How exactly is noise magnetically coupled into a ground lead when the ground lead acts like an antenna?
2. Are magnetic loop coupling, mutual inductance coupling, and magnetic "antenna" coupling different?

For my second question, take for example two parallel wires: a ground lead of a probe and a wire containing a large di/dt or large magnetic field around it.

There seem to be three or more ways noise can magnetically couple into the ground lead.

1. Magnetic loop coupling. When a circuit is connected to an oscilloscope, a loop is formed. Any surrounding magnetic field can enter this loop and induce a current which affects the measurement. I believe I understand this alright.

2. Mutual Inductance in parallel wires. Calculating Mutual Inductance in Parallel Wires. I don't understand the physics behind this.

3. Magnetic "antenna" Coupling, discussed in the video. I don't understand the physics behind this.

Can someone explain these?

If the parallel wires are close together 1 and 2 seem to be valid. When the wires are separated or far apart, 3 seems valid. Are these forms of magnetic coupling the same or different?