How to Detect Bugs & Listening Devices

By Louie Doverspike ; Updated June 01, 2017
Hand holding red phone receiver

Just because you're paranoid, that doesn't mean they're not after you, right? In a society that has shown an increasing disdain for privacy, the threat of electronic surveillance is a rare but very real possibility. A few steps can help you determine whether your home is under surveillance.

Use a Police Scanner

Scour your home with a police scanner to detect radio transmitters. These scanners provide a portable method of refining your search. Carry the scanner around your house, carefully listening with headphones.

Carry a stud detector, too. A change in the frequency of the scanner could be evidence of a bug, although it's more likely to be interference from wiring behind the wall. If interference in the scanner's signal is detected simultaneously with a stud, then a bug is unlikely.

Try a Commercial Bug Detector

If improvised methods aren't working, purchase a commercial bug detector. These devices are designed to vibrate or light up, rather than beep, to prevent eavesdroppers from becoming aware of your search. This will allow you to pinpoint the bug's exact location. Listening devices can operate at any frequency. Most commercial detectors can search frequencies as low as 1 MHz to as high as 6 GHz.

Infrared Photography

Unfortunately, some of the more advanced bugs are designed to thwart the commercial bug detectors, mostly by rapid frequency changes. These more advanced bugs can still be detected through infrared photography, which can pick up the heat signature of a listening device, especially if the wall's surface is first cooled with liquid nitrogen or even a fire extinguisher.

Enlist Help From the Phone Company

If there seems to be no covert listening device inside your home but information continues to leak, it's likely that the device isn't located inside. Many phone providers will search the line outside your house for installed listening devices, either for free or a small fee. Of course, if phone surveillance is being conducted by the federal government, there would be no external device.

If You Still Own a Radio

Using headphones, go slowly through your radio dial and listen for uniform distortion. Bleeps or recurring patterns could indicate the presence of a covert listening device. Most amateur surveillance threats will come in the form of battery-powered radio transmitters that gather sound, then transmit to an outside receiver.

Some Other Tips

  • Shut your blinds to block vibrations from laser-activated passive resonance bugs.  
  • Outside security consultants can be used to guard against more technologically advanced methods of eavesdropping.  
  • Many benign home devices can convey the same microphonic signals as those found in bug sweeps. Sometimes only well-trained technicians can separate the bug from your toaster oven.
  • If the source of a bug is likely to be a law enforcement agency, then it may be illegal to tamper with it. Simply being aware of its presence must suffice.
  • Never use a cell phone for important data. It's easily intercepted.

The Bottom Line

Unfortunately, the spy game is one into which powerful parties have put decades of research and millions of dollars. This means there is no cure-all. There are countermeasures, and then there are countermeasures to the countermeasure. Any steps toward uncovering a listening device should begin with a caveat: If they are truly determined to hear you, you will probably never know, but that shouldn't stop you from trying.

About the Author

Based in Seattle, Louie Doverspike has been a professional writer since 2004. His work has appeared in various publications, including "AntiqueWeek" magazine, the "Prague Post" and "Seattle Represent!" Doverspike holds a Bachelor of Arts in English from Hamilton College.