Warning Signs of
Covert Eavesdropping or Bugging
If any of the following
warning signs apply and you are concerned about covert
eavesdropping or wiretapping then it would be wise to contact
a TSCM SPECIALIST (Technical Surveillance Counter Measure) and
schedule a "Bug Sweep". However, do not call from a suspect
telephone, cellular telephone, or cordless phone and
understand that it is critical that you should get someone out
to your location as quietly, and as quickly as possible. You
may choose to do the sweep yourself with some of our
Counter Surveillance Products.
Are you a potential target? If
eavesdropping on anything you say, write, or do could increase
someone else's wealth or influence, then the answer must be
yes, you are a potential target.
- Others know your confidential business or
professional trade secrets.
This is the most obvious indicator of covert eavesdropping
activities. Theft of confidential information is a
multi-billion dollar underground industry in the United
States. Often the loss of your secrets will show up in very
subtle ways so you should always trust your instincts in
this matter. When your competitors know things that are
obviously private, or the media finds out about things they
should not know, then it is reasonable to suspect technical
eavesdropping or bugging.
- Secret meetings and bids seem to be less than secret.
Confidential meetings and bids are very popular targets for
corporate spies. How would you like the plans for the
corporate takeovers you're planning to become public
knowledge? Would copies of your product designs be of any
use to your competitors? Would it be beneficial for your
competitors to know how much you're quoting for the same
- People seem to know your activities when they
- You have noticed strange sounds or volume changes on
your phone lines.
This is commonly caused by an amateur eavesdropper when they
attach a wiretap, or activate a similar listening device.
Surveillance devices often cause slight anomalies on the
telephone line such a volume shift or drop-out. Professional
eavesdroppers and their equipment usually do not make such
noises; so if this is going on it could indicate that an
amateur eavesdropper is listening in.
- You have noticed static, popping, or scratching on
your phone lines.
This is caused by the capacitive discharge which occurs when
two conductors are connected together (such as a bug or
wiretap on a phone line). This is also a sign that an
amateur eavesdropper or poorly trained spy is playing with
your phone lines. It could be nothing more then a problem
with your phone line or instrument, but a TSCM person should
evaluate the situation to make sure.
- Sounds are coming from your phones handset when it's
This is often caused by a hook switch bypass, which turns
the telephone receiver into a eavesdropping microphone (and
also a speaker). There is probably somebody listening to
everything you say or do within twenty feet of the telephone
(if this is happening).
- Your phone often rings and nobody is there, or a very
faint tone, or high pitched squeal/beep is heard for a
fraction of a second.
This is an indicator of a slave device, or line extender
being used on your phone line. This is also a key indicator
of a harmonica bug, or infinity transmitter being used. Of
course it may also be nothing more then a fax machine or
modem calling the wrong number (but a TSCM person should
evaluate the situation to make sure).
- You can hear a tone on your line when your phone is
on the hook (by using an external amplifier).
To check for something like this you would have to obtain a
"recorder starter" interface (with a VOX option), or some
kind of a high gain audio amplifier such as a uAmp or Kaiser
1059. Then with the phone hung-up listen to your telephone
wiring. If you hear a faint solid dual tone it is a dead
giveaway of someone using a "slave" eavesdropping device on
your (or one of your neighbors) telephone lines. Such
devices create a "command tone" when the subject hangs up
the phone (so you must ensure that all of your phones are
hung-up). On an added note: the most common command tones
for illicit eavesdropping devices are 2100 Hz and DTMF-C,
but any tone combination may be used.
- Your AM/FM radio has suddenly developed strange
Many amateur and spy shop eavesdropping devices use
frequencies within or just outside the FM radio band, these
signals tend to drift and will "quiet" an FM radio in the
vicinity of the bug. Look for the transmissions at far ends
of the FM radio band, and at any quiet area within the FM
band. If the radio begins to squeal then slowly move it
around the room until the sound become very high pitched.
This is referred to as feedback detection or loop detection
and will often locate the bug. The "stereo" function should
be turned off so the radio is operating in "mono" as this
will provide a serious increase in sensitivity. If you find
a "squealer" in this manner then immediately contact a TSCM
and get them to your location FAST.
- You car radio suddenly starts "getting weird"
Keep in mind that the antenna your car radio uses may be
(and often is) exploited by an eavesdropper, and that such
usage may interfere with radio reception (so be concerned if
you automobile radio suddenly starts getting weird).
- Your television has suddenly developed strange
Television broadcast frequencies are often used to cloak a
eavesdropping signal, but such a devices also tends to
interfere with television reception (usually a UHF channel).
Televisions also "suck in" a lot of RF energy and because of
this are very sensitive to any nearby transmitters (this is
technically called "Bandwidth, and TV signals use a lot of
it). A small handheld television with a collapsible antenna
may be used to sweep a room. Carefully watch for
interference around channel numbers 2, 7, 13, 14, 50-60, and
66-68 as these frequencies are very popular with
- You have been the victim of a burglary, but nothing
Professional eavesdroppers often break into a targets home
or office, and very rarely leave direct evidence of the
break-in; however, occupants of the premises will often
"pickup on something not being right" such as the furniture
being moved slightly.
- Electrical wall plates appear to have been moved
slightly or "jarred".
One of the most popular locations to hide eavesdropping
devices is inside, or behind electrical outlets, switches,
smoke alarms, and lighting fixtures. This requires that the
wall plates be removed. Look for small amounts of debris
located on the floor directly below the electrical outlet.
Also, watch for slight variations in the color or appearance
of the power outlets and/or light switches as these are
often swapped out by an eavesdropper. Also note if any of
the screws which hold the wallplate against the wall have
been moved from their previous position.
- A dime-sized discoloration has suddenly appeared on
the wall or ceiling.
This is a tell tale sign that a pinhole microphone or small
covert video camera has been recently installed.
- One of your vendors just gave you any type of
electronic device such as a desk radio, alarm clock, lamp,
small TV, boom box, CD player, and so on.
Many of these "gifts" are actually trojan horses which
contain eavesdropping devices. Be very suspicious of any
kind of pen, marker, briefcase, calculator, "post-it"
dispenser, power adapter, pager, cell phone, cordless phone,
clock, radio, lamp, and so on that is given as a gift. That
little gift the salesman left for you may be a serious
- A small bump or deformation has appeared on the vinyl
baseboard near the floor.
Strong indicator that someone may have concealed covert
wiring or a microphone imbedded into the adhesive which
holds the molding to the wall. Such deformation will often
appear as a color shift, or lightening of the color.
- The smoke detector, clock, lamp, or exit sign in your
office or home looks slightly crooked, has a small hole in
the surface, or has a quasi reflective surface.
These items are very popular concealment for covert
eavesdropping devices. Often when these devices are
installed at a target location they are rarely installed
straight. Also watch out for things like this that "just
appear", or when there is a slight change in their
- Certain types of items have "just appeared" in your
office of home, but nobody seems to know how they got there.
Typical items to watch for and beware of are: clocks, exit
signs, sprinkler heads, radios, picture frames, and lamps.
- White dry-wall dust or debris is noticed on the floor
next to the wall.
A sign that a pinhole microphone or video camera may have
been installed nearby. It will appear as if someone has
dropped a small amount of powdered sugar either on the
floor, or on the wall.
- You notice small pieces of ceiling tiles, or "grit"
on the floor, or on the surface area of your desk.
Prime indicator that a ceiling tile has been moved around,
and that someone may have installed a hidden video camera or
other eavesdropping device in your office or near your desk.
Also watch for cracks or chips in the ceiling tiles. Amateur
and poorly trained spies tend to crack or damage acoustical
tiles. The ceiling tiles in any executive areas should never
contain any cracks, nicks, gouges, or stains. Any ceiling
tile that becomes damaged (for what ever reason) should
immediately replaced and the cause to the damage documented.
In such cases it is also wise to have a TSCM specialist
inspect the area around the chipped, broken, or damaged tile
to determine if a hostile eavesdropping device may have been
- You notice that "Phone Company" trucks and utilities
workers are spending a lot of time near your home or office
doing repair work.
If you see the same or similar vehicles more then three
times then you may have a serious problem (at least
according to the U.S. State Department training course on
- Telephone, cable, plumbing, or air conditioning
repair people show up to do work when no one called them.
A very common ruse which eavesdroppers use to get into a
facility is to fake a utility outage, and then show up to
fix the problem. While they are fixing "the problem" they
are also installing eavesdropping devices. Some of the more
popular outage involve power, air conditioning, telephone,
and even the occasional false fire alarm.
- Service or delivery trucks are often parked nearby
with nobody (you can see) in them.
These vehicles are commonly used as listening posts, be very
cautious of any vehicle which has a ladder or pipe rack on
the roof. Also, be wary of any vehicle which has tinted
windows, or an area which you cannot see though (like a
service van). The listening post vehicle could be any
vehicle from a small Geo Tracker, Suburban, Blazer, Trooper,
or Cargo Van. Look for any vehicle which could conceal a
person in the back or has tinted windows. Also, keep in mind
that the eavesdropper may relocate the vehicle several
times, so look around. Typically, eavesdroppers like to get
within 500-750 feet from the place or person they are
- Your door locks suddenly don't "feel right", they
suddenly start to get "sticky", or they completely fail.
Prime evidence that the lock has been picked, manipulated,
or bypassed. Try to always use biaxial locks with sidebars
(such as ASSA or Medeco). Also, only use double sided
deadbolts in all doors, and good quality window bars on all
windows, and a good quality door bar on all doors not used
as a primary entry doors.
- Furniture has been moved slightly, and no one knows
A very popular location for the installation of
eavesdropping device is either behind, or inside furniture
(couch, chair, lamp, etc.) People who live or work in a
targeted area tend to notice when furnishings have been
moved even a fraction of an inch. Pay close attention to the
imprint which furniture makes on rugs, and the position of
lamps shades. Also watch the distance between furniture and
the wall as eavesdroppers are usually in a hurry and rarely
put the furniture back in the right place.
- Things "seem" to have been rummaged through, but
nothing is missing (at least that you noticed).
A "less than professional spy" will often rummage through a
targets home for hours, but very rarely will they do it in a
neat and orderly fashion. The most common "rummaging"
targets are the backs of desk drawers, the bottom of file
cabinets, closets, and dresser drawers.
When contacting any TSCM firm please remember not to call
from any suspect area, do not use your cellular telephone,
do not use your cordless phone, and do not use any suspect
telephone (instead call from a sterile phone somewhere outside
the suspect area).
Who Gets Bugged?
High Threat Business
- Your company has stock which is publicly traded (or will
- Your company is having labor problems, union activities,
- Your company is involved in any type of litigation or
- Your company has layoffs pending (or they have just
- Your company is involved in the fashion, automotive,
advertising, or marketing industry
Anyone can be the target of
covert eavesdropping, however; some people are under greater
risk than others because of financial position, occupation,
legal, or domestic situation.
- Spouses bug each other on a regular basis
- Parents bug children
- Businessmen bug other businessmen
- Scientists bug other scientists
- Students bug professors
- Attorneys bug other attorneys (and their clients)
- Insurance companies bug accident victims, and other
- Construction companies bug other construction companies
- Salesmen bug clients
- Collection agencies bug debtors
- Police officers bug suspects
- Executive recruiters bug personnel directors
- Rock fans bug rock musicians
- Department stores bug customers and merchandise
Neighbors, Coworkers, Friends, Enemies, Strangers, Your
Industrial Spies, Government Agents, Your Insurance Company,
High Threat Personal
Situations (When to be seriously concerned)
You (or someone close to you)
- Involved in any type of litigation or lawsuit
- Been questioned, arrested or arraigned by the police
- In the process of getting married, divorced, or
- A minister or religious leader (ie: priest, rabbi,
deacon, bishop, elder...)
- Running for any type of elected public office
- Elected to any public office (ie: mayor, selectman,
- Executive or scientist at any large company
- Recently filed a insurance claim
- Engaging in political demonstrations or activism
- Employed by a defense contractor, Department of Energy,
- Private Investigators have been "poking" around
- You are in the upper income bracket
Keep in mind that anybody
with Money, Power, Influence, or access to sensitive,
classified, or personal information is at serious personal
On a related note: If you work
(or have worked) for any kind of military, governmental, law
enforcement or judicial agency the possibility of you being
targeted for eavesdropping is very high. Such eavesdropping
can come from either side of the law, and is rarely legal or
Additionally, people married
to, associated with, divorced from, getting divorced from,
dating, or getting intimate with a member of law enforcement,
private security, PI, or any level of the judicial system
should be concerned about illegal eavesdropping (yes, cops
love to bug their wives and girlfriends).
High Threat Occupations
- Police Officer
- Court Clerk
- Elected to any public office
- School Principal
- College Professor
- Product Engineer
- Software Developer
- Executive at any large company
- Scientist at any large company
- Employed by any defense contractor
- Employed by the Department of Energy
- Any minister or religious leader (ie: deacon, bishop,
- Corporate Buyer or Purchasing Agent
- Scientists bug other scientists
- Employee of a Construction Contractor
- Any type Sales or Marketing
- Labor or Union Official
- Personnel Directors
According the FBI the
following types of businesses are under EXTREME risk and are
popular targets of illegal bugging, wiretapping, and similar
- Materials synthesis and processing
- Electronic and photonic materials
- High-performance metals and alloys
- Flexible computer-integrated manufacturing
- Intelligence processing equipment
- Micro- and nanofabrication
- Systems management technologies
Information and Communications:
- Micro and optoelectronics
- High-performance computing and networking
- High-definition imaging and displays
- Sensors and signal processing
- Data storage and peripherals
- Computer simulation and modeling
Biotechnology and Life Sciences:
- Applied molecular biology
- Computational Chemistry
- Medical technology
- Surface transportation technologies
Energy and Environment:
- Energy technologies
- Pollution minimization, remediation, and waste
Common Frequencies used by Bugging Devices
44.500 - 51.000 MHz Baby and Room monitors (49.83, 49.845, 49.875, etc...)
72.100 - 75.400 MHz Hearing Assistance Systems
54.000 - 150.000 MHz Kit Bugs
78.000 - 115.000 MHz Cheap out-of-band FM Bugs
112.000 - 142.000 MHz Cheap out-of-band FM Bugs
140.000 - 160.000 MHz Cheap out-of-band FM Bugs
60.000 - 320.000 MHz Low Cost kit bugs
398.000 - 406.000 MHz DECO Bugs (398.600/605, 399.450/455, 399.025/030, 406 MHz)
25.000 - 450.000 MHz European/English Kit Bugs
150.000 - 216.000 MHz Typical VHF "Body Wire" & Pro-Grade Bugs
109.000 - 140.000 MHz Digital VHF Pro-Grade Bugs
138.000 - 174.000 MHz Typical "Spy Shop" & LE Cheap VHF Bugs (155-172 Popular)
140.000 - 150.000 MHz Popular Xandi Flea power kits (143/144 MHz)
150.000 - 170.000 MHz Popular Japanese Flea power kits (under 5mw)
150.000 - 220.000 MHz Commercial Wireless Microphones
169.000 - 172.000 MHz 47 CFR 90.265 Authorization *** VERY Popular ***
174.000 - 216.000 MHz 47 CFR 2.106 (NG115) Authorization
395.000 - 410.000 MHz German UHF Bugs (PK Electronics)
365.000 - 455.000 MHz English UHF Bugs (Lorraine/Ruby Electronics)
219.000 - 530.000 MHz English UHF Wireless Microphones (300-500 popular)
470.000 - 608.000 MHz Commercial Wireless Microphones
730.000 - 806.000 MHz Commercial Wireless Microphones
310.000 - 980.000 MHz Sony Bugs (.1mw - 3mw, Spread Spectrum)
470.000 - 489.000 MHz Sony Bugs (2.5mw - 20mw, WFM, Ultra low power)
770.000 - 810.000 MHz Sony Bugs (2.5mw - 20mw, WFM, Ultra low power)
902.000 - 928.000 MHz Sony Bugs (2.5mw - 20mw, WFM, Ultra low power)
947.000 - 954.000 MHz Sony Bugs (2.5mw - 20mw, WFM, Ultra low power)
889.000 - 960.000 MHz Modified Cordless Phones (S/S & Hoppers)
380.000 - 480.000 MHz Video Bugs - UHF TV Channels
430.000 - 820.000 MHz Popular US Video/Audio Bugging Systems
890.000 - 960.000 MHz Video Bugs - US (902-928 Hot)
905.000 - 928.000 MHz Video/Audio Consumer Products (i.e. Recoton)
1.100 - 1.400 GHz Video Bugs - *Very Hot in US/England/France/etc*
1.700 - 1.930 GHz Video Bugs - US
2.400 - 2.500 GHz Video Bugs - US *** VERY Popular ***
3.500 - 4.500 GHz Video Bugs - *Very Hot in England/France/etc*
5.725 - 5.850 GHz Video Bugs - US *** VERY Popular ***
6.200 - 7.500 GHz Video Bugs - US *** VERY Popular ***
8.00 - 12.50 GHz X-band Audio/Video Bugs
20.00 - 26.00 GHz K-band Audio/Video Bugs (Gaining Popularity)
70.00 -110.00 GHz M-band Audio/Video Bugs (Gaining Popularity)