A Bug Detector Circuit from H. Adams, a master designer of simple electronic circuits. This circuit uses a MC 34002 chip and a 9V DC battery for its supply.
Once RF is encountered the piezo alert gos off. It will lead you straight to the source of the RF.
Two different LEDs are included, a red and a green. The green is for on and the red alerts with the piezo. D1 is a standard In34A Germanium Diode.