What Does a Bug Device Look Like?

A bug device is a covert listening apparatus that is a combination of a miniature radio transmitter and microphone. It is used to eavesdrop on a room or an individual in order to obtain information. The CIA, the FBI, and private companies employ bugs to spy on their competitors and gain access to sensitive information.

BUGS OF ALL KINDS (and there are many)

Microwave dishes, which telecommunication firms use to relay voice and computer signals to communications satellites, can be a problem for spies. They concentrate the microwave beams into narrow paths, making it easy for a hacker to intercept the signal and read the messages.


The Soviets used microwaves to bug the new American embassy building in Moscow, and they also hid a lot of other devices that beamed low-level signals into the building. These included reinforcing rods, wire mesh, empty metal cones, and cavities.


They are a little harder to detect than microwaves, but they still can be found. They are usually small, and they can transmit at a variety of frequencies, so they may go undetected even when the target is using an ordinary television.

Several ingenious schemes have been developed to avoid detection by scanners. One is to have the device transmit in short bursts of practically invisible signal. Others have been designed to change frequency in a few thousandths of a second.

Another scheme is to have the device “snuggle” its signal, so it doesn’t interfere with the much stronger TV signal. It is then difficult to find with a scanner, but it can still be detected by an FM-radio or an antenna.

Some bugs, such as those used by the CIA and FBI, are extremely sophisticated. They are built by technicians with extensive electronics knowledge. But a simple homemade device can do the job, too, if you know how to work with electronics and can conceal it from the target.


Some amateur and spy-shop bugging devices are made from inexpensive components, such as microphones. Some of these are even available commercially.

The most common are drop-in transmitters that replace the microphone in a telephone receiver and get their power from the phone line. Other devices, such as those slung into the space above a dropped ceiling, may be powered by AC lines.

Tiny microphones are also easy to make from cheap, everyday objects. For example, a hearing aid microphone is converted into a tiny transmitter by plugging it into the wall. A light switch can also be stuffed with a small transmitter that uses the same source as the phone.

In addition to these more elaborate, high-tech bugs, there are a number of very inexpensive, very small ones that can transmit at ranges of a quarter mile. They are a type of “ghost transmitter” that can record conversations and transmit them for archival or review purposes.


Several companies manufacture middle-range, radio-frequency (RF) signal detectors that can easily sweep a room for hidden bugs and transmitters. These detectors are more expensive than the lower-range devices, but they offer a few additional features that the cheaper units don’t. Some detectors have additional bells and whistles, including signal blockers that help to maintain privacy during the process of detecting a bug.