Audio Bug         

Today, it is possible to intercept communications by means of a number of electronic devices that can be no larger than a box of matches and easily concealable in a number of places. The most classic device is the covert transmitter.

This piece of equipment transmits to a listening post (where appropriate recording devices will be installed) all sounds (in particular conversations) generated in one or more rooms.


Telephone transmitters instead intercept conversations (or fax-data transmissions) through telephone lines and frequently drain their operational power directly from the line. Due to absence of a battery (that needs to be periodically substituted), these types of transmitter are particularly dangerous as their "operational life" is practically unlimited.    Phone Bug
  Mini Video Camera       When audio interception is not sufficient,  covert video-cameras can be used to transmit live video via radio or wire.

Even a common tape-recorder can become a good interception system. Electrical or electronic cables that pass in a room can be used in order to connect a hidden microphone and modem equipped computers can transmit worldwide audio or video signals or can be "infected" with surveillance software or hardware systems. A room's windows can be "illuminated" from the outside by an Infrared or LASER beam that is "modulated" by the window's micro-vibrations caused by voice's sound energy. Even a common air-conditioning duct or water pipe that passes through a room can become a surveillance tool in the hands of an intruder.


Digital Spectrum Analyser Covert radio transmitters usually use traditional modulation (AM or FM) systems, however particularly advanced transmitters will use advanced digital systems (Infinity, Frequency Hopping, Burst, Agile, Spread Spectrum). In this case, only the use of dedicated instruments   (Digital Spectrum Analyzers and Non Linear Junction Detectors) by specialized technicians will reveal their presence as more common frequency counters or broadband receivers will not be sufficient. 
Running specialized software on a Computer controlled Digital Spectrum Analyzer gives us the possibility to document and memorize the radio spectrum conditions of the area to be swept.             Digital Spectrum Analyser Software
Non Linear Junction Detector  

Switched-off or no longer functioning surveillance devices can only be indicated by use of a Non Linear Junction Detector. This expensive instrument is not commonly found in Europe and for maximum effectiveness must be used by properly trained investigative technicians.


Bug sweeping of telephone, electrical and data lines, in particular when the analysed cable is of a length of hundreds if not thousands of metres, can only be conducted by means of a particular instrument called Time Domain Reflectometer (TDR). This piece of equipment can check any type of line (even under power) and indicates on a display screen the presence of abnormalities (short circuits, open circuits, series or parallel connections, inductances, capacities, etc.) and/or parasites.

Time Domain Reflectometer - TDR
Our digital Time Domain Reflectometer has a range of over 11.000 metres with a localization precision of about 20/30 centimetres. This instrument is indispensable when the examined line is very long (try to imagine the route that a cable follows from a telephone switchboard in the basement of a large building to a phone located at the top floor) and not easily accessible (passing through walls, third party property, roads, etc.). 




Non authorized persons are aware of personal or secret facts and documents. 


Confidential meetings, documents, projects and tenders are no longer secret. 


Strangers are aware of when or where you are.


You have noticed unusual sounds, noises or changes of volume on your telephone line.


Your telephone produces strange noises even when the receiver is "on-hook".


Your Hi-Fi or TV system is subjected to strange interferences.


An un-authorized person has entered your offices or home, but nothing has been stolen.


An unexpected gift or appliance has appeared in your office or home. 


You have noticed unexplained variations in the physical structure of your office or home (moved furniture, power supplies, fixtures, carpeting, tiling, etc.).


Suspect vehicles are frequently parked in the vicinity of your office or home.


Utility technicians (electricity, telephone, water, heating, etc.) appear for un-requested or non-programmed maintenance calls.  



If you recently have noticed one or more of these warning signs, you may be the object of covert surveillance. If you decide to contact us for a consultation or counter-surveillance sweep talk about your decision only with who must know and call us from a secure phone that is not situated in the suspect offices or home.





Upon arrival at the sweep site with our mobile counter-surveillance laboratory (designed for Europe-wide travel), our Investigative Technicians will conduct a number of inspections that for logistic and security reasons are preferably carried out during weekends or after normal office hours:  

Radio-spectrum analysis from VLF to SHF frequencies in order to identify covert audio or video transmitters using any  modulation system, either analog or digital.   
Electronic and physical examination of all telephone systems and switchboards in order to identify covert listening systems.
Electronic and physical exam of all rooms, furniture and fixtures with a Non Linear Junction Detector in order to identify covert electronic circuits, of any nature, even switched off or no longer functioning.

LASER and Infra-Red spectrum analysis in order to identify surveillance systems using these band spectrums.  

Electrical and Electronic cable examination.  
Acoustic leak examination.
Physical structure examination of the entire site in order to verify it's global degree of security.



Computer security examination in order to verify the presence of surveillance software or hardware applications, Virus check and hacker protection check. 


Application of propriety anti-tamper seals (both visible and invisible) to all inspected systems and areas. 


At the end of our inspection, we shall deliver a detailed technical report together with a list of suggestions and solutions for site security optimization.


 Photographs from GRUPPO S.I.T. and TSCM Technical Services, U.S.A. archives