Visualizing standing waves along the two parallel conducting pipes using household electronic appliances

We describe an experiment designed to visualize an electromagnetic standing wave by using a video recorder as a source, two parallel conducting pipes as a transmitter, a small dipole antenna as a detector, and a computer with a TV card as a receiver. Students observe the periodic variation of the intensity on a computer or TV display while the dipole antenna scans along the two parallel conducting pipes. The measured wavelengths and computed phase velocities are plotted as a function of UHF carrier frequencies. Two contrasting patterns in short- and open-circuited terminations are consistent with predictions of field theory using appropriate boundary conditions.