Uses a plate antenna which gives high sensitivity over a broad area. Output is to an internal loudspeaker and power is derived from a mains plug-top unit (supplied).

Utilizes a Schottky diode oscillator module feeding a tuned waveguide and horn to give a directional microwave beam. The beam is modulated with a variable frequency audio signal which can be adjusted by the control on the top panel.

Instead of a one-off demonstration use the mini-sonometer to give your students hands-on experience of sound production.
The apparatus is constructed on an acrylic base with hardwood sides measuring 650 × 100mm overall. It has an integral pulley, wire clamp and half metre scale.