Speaker

October 22, 2013: Walter Clark: Two demonstrations that help visualize radio waves, in this case mirowaves

One:
The structure of a radio wave in angle around the direction of travel.
This is called polarization. A spinning bargraph that has a receiving antenna that also spins, will reveal the way radio waves look to a receiving antenna. There is also a demonstration of polarization and ground effect.

Two:
The structure of radio along the direction of travel.
When a receiver is arranged to look exactly in the direction the radio waves are going out, reflections can be measured; just like in radar. The reflection off of the hand or the chest of a child causes the speaker to be loud or quiet depending on the exact position; exact phase relationship. It cycles from loud to quiet every 1.5 cm whether inches away or 20 feet away.