-t.\..A55\f \E:O•..

HANDS-ON ELECTRONIC SURVEILLANCE is designed for law enforcement personnel,government agencies and those civilians with a legitimate use for state-of the-art electroniceavesdropping methods.

This report can be used as a stand-alone guide for modern surveillance methods, but forbest effect should be combined with BOOK 11- HOW TO GET ANYTHING ON ANYBODY,available from Intelligence Incorporated for $38 postpaid, and/or with HANDS-ONCOUNTERMEASURES, as well as HANDS-ON TELEPHONE SURVEILLANCE.

NOTE

It is illegal, in the US, to own devices designed primarily for the surreptitious recording ofconversations and in many states and under many circumstances it is A FELONY to recordconversations without the proper consent or court warrants.

The publishers of this book do not suggest that ANYONE break the law. These techniquesare presented for authorized use only . If you are involved in electronic surveillance, consultan attorney to understand your rights and obligations.

Intelligence Incorporated2228 S. EI Camino RealSan Mateo, CA 94403

Catalog of books, video tapes and equipment for investigators, $5.00.

HANDS-ON ELECTRONICSURVEILLANCE

--lee lapin

ISBN

Copyright 1992by Intelligence Incorporated. Reproduction of any of the contents of this book by anymeans Is strictly forbidden without the written consent of the publishers.

INTELLIGENCE INCORPORATED2228 S . EL CAM INO REAL

SAN MATEO, CA 94403

ii

SOUNDHUNTING

The first consideration of any surreptitious microphone/transmitter should besound attainment. While sound can be transmitted through any elastic substance,consider how easily you can attain sound in the following situations.

Sound takes the path of least resistance, such as a doorway, duct or open window.Check for little overlooked air paths ' over, under or around doors. Sometimes youcan find holes in walls, or spaces around pipes and wiring leading to your subject.

Remember even the smallest air path can transmit sound to your microphone.

Sound-as well as electrical signals-travels along the metal surfaces ofelectrical conduits, pipes and ducts. You can recover this sound after it hastraveled more than 100 feet in this manner. Water-filled pipes transmit soundwith much less distortion than empty pipes.

Sounds, depending on their frequencies, penetrate floors, ceilings and doors.After sound energy hits a structure, some reflects from the surface, some isabsorbed and the rest passes on.

If on a job you run into a "soundproof' room, don't be too alarmed, especially ifthe soundproofing consists of acoustical tile. Truth is, acoustical tile canactually reduce a room's sound security. Acoustical tile was made to reducesound reverberations in a recording studio. Tile lets walls absorb more sound,reducing its level in the room. Sound that is absorbed is not lost because energycannot be destroyed, only converted. Therefore, acoustical tile may reduce aroom's security by allowing sound to be transmitted through the wall structureand it is often applied in a hanging configuration allowing space to placesurveillance gear above the tile.

Most microphones will "hear" through acoustical tile quite well, if not simplypunch a small hole with a nail or dentists drill. This same technique works wellwith video camera lenses. The tiny hole will usually be lost in the tile's pattern.

1

Hanging ceilings, common in office buildingsprovide adequate space for even large transmit­ters or video cameras and recorders (left). Evenflat acoustical tile ceilings provide room for co­vert transmitters.

Distortion and Interference

Sound is distorted when a disruptionchanges its normally smooth pattern.You may encounter distortion thatoccurs before the sound is recorded,during the recording or at playback.Excessive distortion cuts down yourrecovery and understanding of inter­cepted sound.

When placing the microphone, youshould consider how quickly sound losespower after leaving its source. Sayyour friend is talking to you from 10feet away. If you then stand 20 feetapart, the magnitude of his voicedoesn't become one-half as loud-itcuts to one-fourth. The magnitude ofsound declines according to the inversesquare law. If you quadruple the dis­tance between you and your friend, thepower of the sound of his voicedrops to one-sixteenth.

In surveillance work we are interested in two kinds of sound: Sounds (usuallyvoices) we want to hear, and all other unwanted sounds no matter what theirorigin.

Types of sound interference are countless. Rain, plumbing, air conditioning, fans,traffic, planes and trains are just some of the problems. When you monitorsomeone, just one other person speaking in the near vicinity can cause inter­ference.

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Sound waves not only travel from their source, they also are reflected when they hit asurface. Reflected sounds behave as ifthe surface they hit is their original source, and canbe reflected again.

Sound patterns become very complicated after reflecting and re-reflecting from ceilings,floors, walls and internal objects.

Reflected sound waves canmerge almost exactlywith sounds arrivingfrom the first source.Sounds merged like this have an increased sound level and are "in phase."

Sometimes original and reflected sound waves meet so that their decompressions andcompressions neutralize each other. When they merge this way the sounds are "out ofphase." If neutralization is perfect, the effect is called cancellation. Sounds are rarelytotally out of phase, so the nullification effect is usually just called interference.

Test all insertion points to make sure they have no interference. The best way toaccomplish this, as well as to test the transmitter placement is to work with a partnersituated at the Listening Post. By communicating with walkie talkies you can quicklydetermine the best spot for placement.

Whether hardwiring, stashing a recorder or placing a transmitter, the prime rule torememberis: the closeryou place the microphone to the people speaking, the more likely youroperation will succeed.

The average male's speaking voice falls between a frequency range of 100 Hz and 8 KHzand the average female's between 200 Hz and 10KHz. Most speech falls between 600 Hzand 4 KHz. You can sharply reduce interference without sacrificing clarity and under­standingby reducing the power offrequencies between 600 Hz and 4 KHz. Some recordingsystems come with filters that limit the band pass to achieve this reduction, automaticallyreducing sounds outside of the voice range. Early telephones did this by virtue of theircarbon microphone construction.

Rooms constructed with hard surface walls and containing filing cabinets, desks and othersuch furnishings are known as "hard rooms." Hard rooms reflect sound waves a great deal,creating a feeling ofloudness despite a lack ofloud sounds.

On the otherhand, "soft rooms" are fitted with acoustical tiles, soft. walls, padded furniture,drapes and carpets. Soft rooms absorb sounds and cause a feeling ofquiet regardless ofthepresence ofloud sounds.

3

Soft rooms pose fewer surveillance problems than do hard rooms. Hard rooms reflect soundmore, causing distortion. By its construction, a hard room's structure multiplies the effectsof disturbances and interference.

If you have the opportunity, test several spots in the target room to find the one with theleast amount of annoying distortion. Some operatives take a surreptitious photo of theroom on an earlier visit and then pre-plan the actual placement by experience or byexperimenting with a similar room. This is often possible ifthe target room is a motel roomor apartment with duplicates nearby.

STASHING THE MICROPHONE

When you select a place for microphone stashing, remember to place it as close as possibleto where the talking will take place. Avoid sites that will cause the microphone to pick uptoo many reflected sounds. For instance, placing a microphone in a file cabinet, or metalwastepaperbasketcould add echoes thatwould make anyreceived speechincomprehensible.

Besides finding a good location to hide the microphone, you must check for and try toremove any sources of electrical interference. Sources you cannot remove require diligentplacement of both cabling and the actual microphone.

Electrical hum comes from motors, transformers, SCR dimmers and electrical wires. Manyappliances cause hum and noise. Always strive to place your microphone cables away fromthese sources of hum. When you must bring microphone cable across electrical wires, doit at a 90 degree angle to reduce induction. Ifyou still pick up 60 cycle hum from buildingwiring or fluorescent lamps, it can usually be notched out after recording.

The best places to conceal a microphone are those above a standing person's eye level orbelow a seated person's. People do not often scrutinize these areas. Also take advantage ofany obstructions you can stash a microphone behind.

Even though doors, ceilings, walls and floors are many times hollow, they seem solid andpeople imagine them to be free of suspicion. Consider planting microphones inside thesesupposedly solid locations. Inside walls has the added advantage of nearby wiring withwhich to power your transmitter. A tiny hole can be drilled for the microphone, or existingholes such as those in electrical sockets can be utilized for sound gathering.

Ceilings offer benefits when concealing microphones. Crawl spaces and attics can giveroom in which to work, remember sound goes through most acoustic tile so the microphone

4

Air ducts in commerical buildings offer many advantages to the eavesdropper including large areas fortransmitter placement, sound collection from adjoining rooms and sometimes even access to "locked" officesfor installation.

til

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can simply be placed on it without the need to drill holes. Outlets, fixtures and ducts aregood places for a microphone, provided there is no acoustical and electrical interference.

HARDWffiING

The safest method in which to place an area under surveillance (safe with regards toobtaining the needed sound) is to hardwire it. This entails secreting a miniature micro­phone in the area ofinterest and then bringing the electrical signal out to your listeningpost, or a hidden recorder, by the use of wires.

One method of doing this is to lay fine copper wire (purchased or unwound from a flybacktransformer) around the edge of the floor and out to the LP.

You can easily hide microphone cable with carpeting. Separate the pile down to the carpetbacking, tack cables to the backing with small wire staples, then smooth the pile back tocover your cable.

Wall-to-wall carpets are usually set in place by being pressed into small points sticking outof thin wood strips mounted on the baseboard. Use a pair of pointed pliers to separate thecarpet from the strip. You can lay wire between the wall and the strip; or on the strip,making sure the sharp points do not puncture the insulation and short out the wires. Thenreplace the carpet.

The longer a cable is the more chance there is ofits discovery. You should always maintainthe shortest possible cable run for best results.

It is also possible to utilize in-place wiring for your cable run. The most convenient wiresare usually those conveniently installed by the friendly phone company. Ifthe target roomhas a phone, and just one line, the black and yellow wires insthe phone cable are unusedand will carry signals back outside the building where they can be picked off at theoperator's convenience.

Specialized recordings require special equipment to work effectively. Ifyour subject is ina large room, the level of the recording will vary considerably, making the recording lessthan coherent. A compressor/pre amp unit will solve this problem by maintaining aconstant input level to any recorder. Low level sounds, or moderate length cable runsrequire the microphone output to be increased to provide enough signal for successfulrecording. A preamplifier that powers and boosts the output ofyour condenser microphoneshould be used to compensate for these situations. This will also work quite well for covertbriefcase applications or body (wire) recording.

6

Professional surveillance experts never use a simple electret mic for hardwire work thatcovers any distance. Why? Recording amplifiers and pre amps boost the line noise alongwith the signal creating strong audio interference. The cure for hardwire hangups is toemploy a combination microphone and amplifier/driver at the FRONT end ofthe cable thattransmits a high level signal to the recorder. The mic must be phantom powered from therecorder and include an interface for proper connection impedance. Good line drivers willbe sensitive will work over several thousand feet ofunshielded cable ifnecessary and havethe added advantage ofbeingpowered from the LP rather than from inside the target room.

A nice selection of mic elements, preamps, compressors and line drivers is sold by:

Intelligence Incorporated2228 S EI Camino RealSan Mateo, CA 94403

Sometimes you cannot enter the target room or at least you should not enter, because ofpotential countermeasures or difficulties in hiding the microphone. Use specializedmicrophones outside the target room in these cases.

A tube fastened over the microphone opening exposes its diaphragm to airpressure. Soundpressure variations travel great distances through the tube, depending on its diameter andcomposition. Seal the microphone onto the tube itself, and insert the tube's other end intoany hole that reaches your target.

Hotel or motel, rooms connected to each other often have electrical wall outlets back toback. Take off the outlet cover on your side for tube access to the target. Telephone,television antenna or cable TV outlets might also give handy access.

Using a plastic tube lessens the danger of your operation being found by a metal detector.Your device and wire stay with you in the listening post. It does not matter ifthe tube canbend or is inflexible, but you should insulate it completely from building vibrations.

Sound waves usually move in a straight line between two points. But sound penetratinga pinhole in a wall behaves differently. Whatever angle the sound originally comes from,when it goes through a pinhole it exits behaving as ifit came from the hole. Therefore, youcan place a microphone on the exit side of the pinhole to pick up sounds no matter fromwhat direction they first came.

Any sounds traveling through the pinhole have less strength than those on the "hot" sideofthe wall. Make sure you install the microphone with an airtight seal against the pinholeside of the wall to avoid losing more sound energy. Silicone caulking is good for thisoperation.

7

You should seal the microphone at the pinhole also to avoid the barrel effect. This effecthappens when a microphone is situated in dead spacein a wall. Bouncing waves in this areadistort sound so it sounds like someone talking into an empty barrel.

Crystal transducers can be attached to a wall next to the target room. Sound waves in thetarget room vibrate the wall, and a crystal transducer transforms the mechanicalvibrations into an electrical copy of the target sounds.

Regular ambient sounds in the room vibrate the walls and create problems of extremeinterference, so crystal transducers provide minimal acoustic quality, but it will workagainst thin walls and may be your only choice in a "sudden" situation.

Traditional thru wall vibration monitors are gradually being replaced by devices knownas accelerometers.These are very sensitive units used by engineers to readminute changesin g forces on a surface. They can also be used to reproduce the tiny changes as sound.

Accelerometers are a viable alternative to vibration microphones.

The best two traditional thru wall mic/amp combinations are made by:

MICRO SECURITY ELECTRONICSEfftingestr. 192000 Hamburg 70Germany

and KAISER ELECTRONICSPOB 171Cockeysville, MD 21030

Accelerometers designed for surveillance purposes are sold by:

SECURITY RESEARCHFreepost NH4756Cavendish CourtyardSallow RoadCorby NN17 IDZEngland

Army, or I guess the correct term would be NASA surplus, accelerometers are availablefrom:

ILIADIS1760 Dibble Circle WestJacksonville, FL 32216

8

It's also possible to combine hardwires and transmitters. Hardwire the transmitter at thesite to an RF transmitter, which does not have to be at the site. You can then pick up soundfrom the target room with your receiver at a remote listening post.

Whatever system you use, it must be comprised of:

1: A microphone of some sort that transforms sound into electrical energy.

2: Cable or connection to the receiver. Hard wired systems are risky, but in cases where thetarget site already has wires, consider their use. Use RF links preferentially, because theygive better security by letting you hide from remote with the receiver.

3:Alisteningpost. Itneeds amplifiers or receivers to convert electrical energy to sound loudenough for you to understand. Hard-wired systems need an audio amplifier with gainfactor sufficiently high enough for you to hear or record sounds.

Your receiver and transmitter mustbe compatible in frequency and how they modulate thesignal. The receiver needs to be able to discriminate from other local RF signals, andsufficiently sensitive to pick up the lower energy typically emitted by hidden transmitters.

Finally, you need speakers or a set of earphones, which simply reverse the process of amicrophone converting sound waves into electrical energy. For permanent storage, courtappearances or just sharing with friends, use a tape recorder.

RADIO FREQUENCY SURVEILLANCE

You will need to choose between installing a RF or hard-wired system, depending on theneeds of your surveillance operation. The benefits of using an RF system include:

You can conceal a transmitter on your person or in a vehicle. The time you spend droppinga transmitter in the target area is minimal. No one can trace the transmitter back to you,and you have greater latitude in choosing your receiving post. Because the transmitter isa usually a single unit with its own power, you will have fewer installation problems.

The problems of using an RF transmitter include:

You must return to the site to replace batteries if any are used.

9

A discovered or not retrieved unitnormally means the loss ofexpensive equipment. Simplecounter-measure gear can detect most transmitters. Other RF signals, random noise andintentional jamming can cause interference. Drug dealers and hackers have interferedwith law enforcement transmissions by jamming and a couple of vendors now offercommercial jamming units.

Frequency Ranges

A surveillance transmitter's frequency usually falls between 20 MHz and 500 MHz.Commonly available items such as "baby sitters" or "wireless microphones" use thecommercial FM band of 88 MHz to 108 MHz. But ifyou have enough skill and resources,you can use nearly any RF frequency.

Ifyou are going to use a baby sitter or wireless microphone transmitter, set the

operating frequency a fraction below 88 MHz or a little above 108 MHz by adjusting thecoil. Commercial FM receivers will then have a reduced chance of picking up yourtransmission. Endeavor to pick an unused frequency. FCC-allocated frequencies arepublicinformation, so a little research will show you the clean areas ofthe spectrum in yourvicinity.

Technical surveillance generally uses three frequency bands. They are low band VHF, 36to 50 MHz, high band VHF, 150 to 174 MHz; and UHF, 450 to 512 MHz. You tune afrequency by changing the mixer resonant circuits, RF amplifier and local oscillator at thesame time for best results.

Each frequency band has its own conditions you will want to consider in your choice.

Low band VHF frequencies do not lose as much power when traveling far. However, theyare very bad at penetrating structures. Low band VHF signals suffer skip interference andhave limited area saturation.

Buildings often are made with steel structural members, rods for reinforcement, concreteand metal panels, all elements that hinder radio waves. Consequently doors and windowscould wind up being the only openings for radio waves in these structures. Low band VHFsignals have wavelengths of 19 to 33 feet, too long to escape intact from small openings.

Skip interference occurs when long-traveling signals reflect strongly from the ionosphereback to earth. Area saturation is the condition ofa radio signal reflecting and rereflecting.Low frequencies reflect less, causing dead spots and shadows.

10

If you need to send signals where land masses block the path, use high band VHF. Thisrange also penetrates buildings well, but is less successful than low band VHF for line-of­sight transmission.

For optimum transmission through an environment filled with metal structures, use theUHF band.

The higher your signal's frequency, the shorter distance it can travel. High frequenciespossess short wavelengths and vice versa.

For long range transmission, low band VHF is good, high band VHF medium, and UHF isbad. To avoid skip interference, the best bets are UHF or high VHF, with

low VHF faring not so well. Use UHF to achieve the best area saturation, high VHF whenthis is of medium concern, and low VHF when it is oflittle concern. When the area posesa great deal of structural interference, UHF gives your signal the best passage, high VHFa medium success rate, and low VHF a negligible showing at best.

You can utilize one of two types ofFM transmitters. The cheaper transmitter is one thatis tuned to the operating frequency by an inductance/capacitance integrated circuit. Itexhibits frequency drift often and is called "free running." The free running circuit, usuallya micro miniature device, transmits in various bands but the cheaper units usually live inthe commercial FM band.

The FCC has recently enacted a law which prohibits, or at least restricts, the selling ofFMtransmitters to unlicensed operators. Most of these "hobbyist" units are now required tobe offered in kit form; the logic being that a true electronics' hobbyist shouldbe able to buildhis own unit.

Several companies have edged around the kit laws by offering their units completelyconstructed except for the soldering of one component, usually the microphone element.The best free running transmitter I have personally found is made by:

DECO INDUSTRIESBox 607Bedford Hills, NY 10507

This unit uses surface mounted components, IC chips instead of discrete transistors, isfairly stable and serves as a dual purpose unit. Ifyou solder the microphone on it works

11

as an area transmitter ("bug")t ifyou utilize the other two contacts it works as a telephonetransmitter.

Range on this unit is quite goodand it is stable enough that a goodAFC receiver or scannerand track any drift and record the signal without constant re-tuning.

THE DECO VT-75 Voice and telephone transmitter unit (right). Solder one component Pre-tuned to the lowend of the broadcast FM band it is tunable up to 130 Mhz with only a screwdriver. Runs on any power sourceform 3-12VDC.

(Left.) Cony micro transmitter. Not as stable as the Deco but still a deal for those thirty dollar drop-insituations...

Law enforcement agents and serious surveillance folk will more likely employ the othertype, the crystal-controlled transmitter. Its quartz crystals regulate the exact theoperating frequency allowing for little frequency drift. Crystal controlled units are usuallya bit higher in price butt for the most part, well worth the difference as you will experiencefewer problems with receiving the unit's signal.

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A couple of publicly accessible companies offer crystal controlled transmitters andmatching receivers (although a regular receiver or scanner can be used) at prices far lessthan those charged by traditional law enforcement manufacturers.

One of the best units I have tested is made by:

RUBY ELECTRONICS LTD.(Lorraine Electronics Surveillance)716 Lea Bridge RdLeyton, London E10 6AWEngland

Small, selfpowered, available inbotharea and phone configurations, extremely stable andcan be used with a nice little crystal controlled receiver that is small enough to carryunobtrusively in a coat pocket.

A RUBY crystal controlled surveillance transmitter and dedicated receiver. Small, sensitive and quiteinexpensive. Ruby units are well designed and preform as advertised, somewhat of a rarity in this field...

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Another CC unit is made by:

C.A.Z39 Star StLondon W2 1QBEngland

The Japanese check in with a dedicated transmitter and mini receiver made by:

KANT CORPORATIONShiba POB 145Tokyo, Japan

and sold by a number ofJapanese companies. All ofthese units from the Ruby on down areoffered by American suppliers at inflated prices.

Think carefully about how much RF power, you need to use. While more power increasestransmission range, it also renders your operation more vulnerable to eavesdropping onyour eavesdropping and countermeasures. Always use the minimum amount of powernecessary to get the job done.

Ifyou only need to transmit sounds from one room to another nearby room or vehicle, youcan probably get by with a subminiature unit powered from hearing aid batteries. Do notuse such a device when transmitting for hundreds of feet, or penetrating commercialbuildings, despite advertising claims ofviability for more than 1,000 feet. It just ain't truepal.

A transmitter's range has to do with the degree ofRF power as well as the efficiency oftheantenna. Range, efficiency and optimal power usage decline with any design change oftheantenna affecting its tuned length.

Subminiature devices modified to fit inside cigarette packs, ash trays and shoe heels haveinsufficiently long antennas. Their range is quite limited, compared to what it would be iftheir antennas were of proper length.

You run a risk of being easily detected when using cheap commercial "wireless micro­phones" because of the frequency range they transmit and the amount of spurious signalscalled harmonics they produce.

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If you feel there is absolutely no danger of someone looking for the unit, or tuning acrossit accidental while operating an FM receiver in the vicinity, you can use of these devicesin a pinch, but remember anyone listening to a nearby radio may run across the signal orthe traditional feedback howl when the transmitter is operating nearby.

Pick what kind of device you require based on the power needed to receive its signals, andhow much time it takes to install the unit and your budget for the job.

Determine preciselyhow much power you need, because the less RF power emitted, the lesschance of detection. Balance power needs with simplicity of installation. Ifyou know youhave little access time, use a transmitter with its own power source and integral antenna.The time you save in simply dropping the device under a chair outweighs the drawback ofradiating excess RF power.

The best method is to still conduct an effective audio surveillance by correctly installinga modern crystal controlled transmitter along with a proper antenna. A range of at leastone mile can be achieved with careful planning and the use of a sensitive receiver at thelistening post.

A carelessly placed unit, i.e., tossed underneath the file cabinet or buried in a planter, willsimply not overcome its poor placement to convey the necessary intelligence.

Part ofthe problem is a something known as the "cocktail party effect"; this happens whena microphone is not located at the center of the target conversation and only transmits anunintelligible babble instead of coherent information.

At a party, your earcan selectively focus on only one conversation and filter outbackgroundchatter. The microphone you hide behind a painting or in the ceiling is not so blessed andwill pick up and transmit all noise at the same level.

This makes it difficult at the listening post to make sense of any the babble. To avoid thiseffect, try to anticipate where your targeted conversation will take place and center themicrophone there.

Another thingyou should consider when placingthe microphone is how quickly sound losespower after leaving its source. Say your friend is talking to you from 10 feet away. Ifyouthen stand 20 feet apart, the magnitude ofhis voice doesn't become one-halfas loud-it cutsto one-fourth. The magnitude of sound declines according to the inverse square law. Ifyouquadruple the distance between you and your friend, the power of the sound of his voicedrops to one-sixteenth.

15

Opportunities for transmitter placement in this room would include: an AC transmitter in the lamp base,a battery unit behind the board over the top ofthe curtains, behind the painting on the wall, under the chestof drawers, (horizontal antenna polarization, limited range) under the chair (difficult audio pickup,horizontal antenna placement, behind the headboard ofthebed, hungin drapery or behind blinds on window,in upholstery of ottoman (difficult-limited range), behind bookshelf, vertical antenna down side.

-~

~Ir

VI-....;:::

~~~

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Closeup of headboard installation (left). Note vertical antenna placement, large parallel battery pack,microphone near center of conversation. On right is a long term in-wall unit. The transmitter is wired viaa voltage reducing transformer to the hot side of the switch (so the switch win not affect its operation) andthe microphone is glued over a pinhole in the wan . Back the mic with silicone caulking or foam rubber.

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Consider snuggling when you choose an operating frequency. Set the operating frequencyof your transmitter near the operating frequency of a nearby, high powered FM station.Commercial FM receivers normally lock on a strong signal and will ignore yours makingthe chance of discovery a bit less.

Some programmable receivers will reduce the nearby station's strength to more easily pickup your signal. Anyone performing a countermeasures sweep with a cheap RF receiver orfield strength type meter will be hard pressed to discover your snuggling signal.

Another good idea is to use a carrier current transmitter instead of an RF unit. Carriercurrent transmitters broadcast along telephone or AC electrical lines. They throw little RFinto free pace because the operating frequency is between 50 KHz and 250 KHz, the verylow frequency (VLF) area of the spectrum.

You can conceal carrier current transmitters anywhere along AC power lines near yourtarget. Hide them in appliances, wall power sockets or lamps, for example.

The low frequency and negligible radiated power of carrier current transmitters are lesseasily detected by countermeasures receivers than transmissions broadcast throughspace. Battery problems disappear because energy comes from AC lines.

The "stock" carrier current transmitter-receiver combo is the Radio Shack WirelessIntercom. This unit will transmit room conversation over the wiring in a building orbetween buildings where the electrical wiring does not pass through a power companytransformer.

Carrier current units are cheap, effective, do not require batteries and are hard to find.

Repeaters

One way to get around the problem of range vs. power in covert operations is to use arepeater. This principle has been used by ham radio operators for years in order to get longrange from a handheld transceiver, the conceptis now utilized in surveillance applications.

A repeater is a unit that picks up the low level signal of your original transmitter and thenfeeds it to a more powerful transmitter operating on another frequency. Most smallrepeaters utilize a walkie talkie for the second transmitter. Good repeaters do not tum onthe second transmitter until audio is received from the covert unit.

17

/'

The electrical wiring in large buildings can be used to effectively secret one or more carrier currentdevices in different offices, even on different floors. Radio Shack wireless intercoms work as well as theirmore expensive law enforcement cousins. Be sure each installation is on a different frequency for simul­taneous monitoring.

18

~-'--1: :r .-+

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--------------------------, .1171 ... -....

! ~~I

0-+1 T ~ I DIOOII I• I._--------------------------

Three examples of successful electronic surveillance applications. The top is a hardwired job where thetarget room is miked and a cable is run to the listening post and then to a recorder and a speaker.

Second is an example of a combination hardwire and RF operation . The target room is miked, wired andthe signal is carried to a more convenient location for the transmitter. the signal is then broadcast to the

actual listening post.

The bottom example illustrates the use of a repeater - a low powered bug is placed on site, the signal isdirected to a nearby repeater site which contains directional antennas. a receiver tuned to the bug'sfrequency, the repeater and a transmitter of between 2-50 watts . The "new" signal is then broadcast to the

listening post.

19

A repeater needs to be small, portable, lightweight, very reliable, easily hidden, andcapable of generating a high enough RF power transmission from its own power supplylong enough to cover any operation.

Repeaters are often stashed in cars which can be parked within range of the coverttransmitter. They will then re-broadcast the signal several miles to a permanent listeningpost armed with a sensitive receiver, or in a pinch, another walkie talkie on the samefrequency.

Your repeater's receiver section shouldbe sensitive enough to pick up and pass along weaksignals and be sufficiently selective to perform in an area crowded with many othertransmitters.

In order for you to keep your listening post far enough away from the target area to avoidattracting attention, yet close enough to do the job, the repeater's transmitter needs toprovide sufficient RF power. This set up allows you to use a very low powered bug and yetlocated the LP a safe distance away.

Pay attention also to your power output, because despite picking a clean frequency,commercial receivers sometimes use a signal seeking tuner that would lock onto yourrepeater if it sends out a high power RF signal.

A very nice repeater (for law enforcement use) is sold by:

SWS SECURITY1300 Boyd RoadStreet, MD 21154

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I

The SWS PRT-1 is designed to work with an ICOM walkie-talkie. Itdraws its power from the radio to whi:it is attached and extends the range oflow powered surveillance devices or two way radios. The RPI'-1 Cl

be body worn, carried in a briefcase or placed in above a drop ceiling for quick plant applications.

It is also possible to construct your own repeater, or have one made for you, from a setplans produced by:

TECHNOLOGY 2008POB 5264Augusta, GA 30906

or use a ham radio/commercial repeater from:TELEMOBILE19840 Hamilton AveTorrance, CA 90502

21

TRANSMITrER PLACEMENT

To perform successful transmitter surveillance, you need available audio, proper conceal­ment and strong RF signal paths. Your first job is to ascertain the conversation's center,in order to pick up goodaudio. Ifthe target is in a car you merelyneed to learn who is sittingin what seat to do the job. When you wear a body transmitter, the center of conversationwill automatically be three feet in front of you.

After you pinpoint the center of conversation, figure out potential sources of interference,locate the microphone as close to the center of conversation and as far from interferencespots as possible.

What length oftime you can spend in the target room, and other factors will determine howyou install a transmitter. Your transmitter might be a disposable unit that you drop in apotted plant or trash can, or it mightbe a sophisticated unit that needs more time on targetfor installation.

The transmitter might have a standard flexible wire antenna or a high gain type forextended range. Position either type of antenna vertically so the waves can radiate in alldirections. or better yet. point a directional antenna directly at your LP ifyou know wherethat will be located. Remember it's always wise to check out the signal path by talking toyour partner at the LP as you position the transmitter.

Metal objects just a few inches from the antenna. or large metal structures like desks orfiling cabinets within two wavelengths of the transmitting antenna will attack the wavepattern. usually to the detriment of the transmission so avoid them if possible.

22

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AUTOMOBILE SURVEILLANCE

If you install a transmitter with a regular antenna in a car, your operating range will besharply restricted by the metal body ofthe vehicle. Position the antenna outside the car byusing an antenna diplexer that allows the use of the existing radio antenna. An antennadiplexer will still allow normal use of the car's radio.

Acoustically speaking, the best place to locate the microphone in a car is along a linebetween the windshield's top center and the center of the roof. From this position you candetect sound from any seat and avoid noise from gears, stereo speakers, windows, ventsand the floor. You need skill in upholstery to remove the ceiling fabric, install microphoneextension cord, and replace the fabric so no suspicions are aroused.

Whenever possible, use the auto's electrical power supply for your transmitter. Employ avoltage regulator to maintain a rock solid 9 VDC from the car's 12 to 13.5 VDC system.

PEOPLE TRANSMITIERS

Transmitters that work attached to a live body (usually called "wires" or "bodywires") arean importantpiece ofsurveillance gear because they can be used by an agent, or on a snitchand provide a movable feast ofaudio thatboth followsthe target and can warn ofsituationsthat may become dangerous to the wearer.

Normal surveillance transmitters are not usually suitable for body wiring; free runningunits will have their frequency affected by the person's inherent capacitance, the mics arenot designed for the job, clothing noise will mask out conversation and they are usually tooweak in power to do the job effectively.

Law enforcement body transmitters are sold by a number of people including:

3-1 Inc.POB 904Punta Gorda, FL 33951

emx Inc.POB 195039Winter Springs, FL 32719

It is also possible to use a civilian (much less expensive) counterpart; the wireless film orvideo microphone. Do not utilize a cheap non-crystal controlled special here because youwill lose contact just at the exact moment the target says, "okay here's how we'll do the job,I get the gun crackle, hiss...

I personally guarantee it.

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Instead use a unit from:

NADY SYSTEMS6701 Bay StreetEmeryville, CA 94608

The Nady is crystal controlled, works on VHF frequencies, is available with a matchingcrystal controlled mini receiver with both earphone and audio out or an AC poweredreceiver with built in bar graph to indicate the audio and signal strength.

The transmitter is in the under $200 range and gives an honest range of 500 or so feetdepending on terrain and buildings involved. The mic is on a separate cord and must bepositioned correctly. Pick up range is not great as this unit is designed to transmit thewearer's voice only,so the target must be fairly close in order to pickup both sides of theconversation.

All wires should be mounted with the transmitter, microphone and antenna secured yourbody with surgical tape or elastic bandages. You can wear a transmitter with an RF outputofone-halfwatt or less close to your skin with little fear ofthat unpleasant smell ofburningskin.

Unless the antenna was made for people use, separate it from the skin by 1/8" for the bestsignal radiation. Use thin sheets offoam rubber as a buffer. Also it is a wise idea to separatethe transmitter from your skin with at least one piece of tape.

Transmitters are never completely efficient in converting their power into RF so take myadvice and protect yourself from heat injury by wearing at least one layer of insulationbetween the transmitter and your skin. Remember this piece of advice 'specially whenusing units of higher power. Moleskin can be used as an effective buffer layer.

Your body will affect the RF radiation pattern, reducing the effective range of any wornunit.

The radiation pattern is not the same in all directions from the wearer. Waves propagateforward from the antenna, centered at 320 degrees when you wear the antenna vertically,left of center on your chest. Waves lose power moving toward your back because your bodyabsorbs part of the signal.

Separate the antennas from microphone cable as best as you can to avoid interference.Position the antenna vertically for maximum range. For maximum wave propagation you

25

should stand and not fold your arms across your chest as that will disturb the radiationpattern. If the wearer sits down, the signal will be reduced to a slight degree.

One ofthe major problems with a body wire is that the wearer tends to be nervous, but thisfeeling will fade in time. Because you are not used to wearing a bug, it is natural to feelpeople can see its shape and know what it is. Ifyou have placed it carefully, this is not true,others are not aware of the transmitter just because you are.

As agent in place, your job is to shut up and listen so that sound recordings can be madefrom the signals. Refrain from adding "uh huhs" or small talk. Do not lean against metalstructures such as filing cabinets and desks which can absorb or disrupt your transmitter'sradiation. Train yourself to limit body movements and disruptive sounds.

Additional "civilian" body mics are available from:

SECURITY RESEARCHCavendish CourtyardSallow RoadCorby, England NN17 lDZ

The NADY video professional video mic doubles as a body wire. Shown with both the portable and ACpowered receivers.

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POWER SUPPLIES

Electronic devices used in investigative applications should be flexible in implementationand operation. More than 70% of the failures of electronic investigation devices are causedby mishandling of the batteries.

If you reverse the polarity of the batteries, you can cause extreme damage to delicatecomponents. Insufficiently charged batteries cause feeble transmission or poor reception.Spent batteries allowed to remain in their holder can leak corrosive acid that will destroythe transmitter.

Batteries contain stored energy. Chemical reactions inside the battery convert to electricalenergy used for our devices. A "battery" is a one or more cells, or basic units. A battery hasa terminal and insulation if one cell, or more terminals and insulation if composed ofmultiple cells.

A battery's capacity is defined by its current output measured over a set amount of time,rated in ampere/hours (AIH) or milliampere!hours (mAIH). Battery capacity is rated interms of optimum drain rate.

You should compare the manufacturer's recommended drain rate with the needs of yourunit to estimate the useful operating time. Battery capacity might be 2,450 mAIH with thedrain rate being 245 mAJh, giving you ten hours of power. Ifyour unit has a higher drainrate, the battery will not be merely drained more quickly, but also less efficiently. For thisbattery, you will not be able to draw 735 mAJh for 3.3 hours-that rate will deplete thebattery in fewer than 3 hours.

Battery Types

Carbon-Zinc

CZ batteries are unsuitable for investigative operations. Their open circuit voltage is 1.5volts, but their nominal voltage ranges from underhalfthat to 1.2 volts. The discharge ratereduces drastically early on, and the batteries are prone to leaking.

Alkaline

Alkaline batteries have a long shelf life, operate well under low temperatures, produceaboutten times the output time of their carbon-zinc cousins and have a fairly stabledischarge rate.

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Alkaline open circuit voltage is 1.5 volts and nominal voltage of about 1.2 volts.

Mercury

Mercurybatteries are a goodchoiceexcept under extreme temperature conditions, becausethey lose power quickly under 50 degrees F. Their discharge rate is fairly stable even underheavy drainage.

Open circuit voltage is 1.4 volts and nominal voltage is around 1.3 volts.

Silver-Oxide

Use silver-oxide batteries only to power devices with low drainage rates, such as Cony typeRF transmitters or active antennas. They have a very stable discharge rate. The opencircuit voltage is 1.6 volts, nominal voltage is 1.5 volts.

Lithium

Lithium batteries are usually a good selection because they can operate at temperaturesfrom -40 degrees F to +165 degrees F with a stable discharge rate. Theiropen circuit voltageis 3 volts and nominal voltage is 2.8 volts.

Nickel-Cadmium

You can use and recharge nickel-cadmium batteries literally hundreds of times. They arewell-suited for powering units with high drainage rates because their internal resistanceis very low and the discharge rate is stable. As long as the battery is fully charged, the opencircuit voltage will be 1.4 volts while the nominal is 1.3 volts.

Nieads suffer from a weakness known as "memory". If you partially discharge a nicadseveral times in a row it may acquire a memory and only hold a partial charge. If you usenicads discharge themcompletely at least once a month. Alsonote many commercial nicadsare rated above their actual operating voltage. Most 9-volt nicads are, in reality, on 7.2volts, which will result in reduced range when used in a transmitter.

Check your nieads with a digital YOM or purchase those clearly marked at a true 9 volts.Radio Shack, among others, sells a "true" 9 volt nicad battery.

You can connect any similar batteries in parallel to boost their capacity or their ability todrain current. Ifyou add batteries inparallel, you can elevate their time on target and drainrate.

28

Divide the current drain of your unit by the number of batteries you use to learn theworking drain rate for each battery. The drain rate for each battery declines, and theoperating life increases as you stack batteries in a parallel configuration.

Make sure you connect the batteries with the correct polarity. If you accidentally reverseone battery in a stack, a short circuit results. The rate ofcurrent flowthrough the miswiredbattery is restricted only by the batteries' internal resistance and that of series inter­connections. The resulting high current flow generates too much heat for and could causean explosion.

The agent should stay clear ofbackground music, not foldher arms, stand next to large metal objects, or talkunnecessarily.

29

- - -Conceal the transmitter utilizing the naturallay of the land. Insulate the unit and the antenna with foam 'rubber or ACE bandages. Extend the antenna fully and position the microphone close to the center of thechest.

You can customize voltage and operating life by connecting batteries in series/parallelcombinations. Sometimes you will need batteries with a longer than standard operatinglife. Whip up a battery pack that will satisfy the particular requirements.

Consider the following limitations required operating time, target area temperature, theequipment's voltage needs and current drain, the battery's capacity and voltage rating,and concealment parameters.

Ifyou find a battery with the needed voltage rating, just keep adding batteries in paralleluntil you reach the proper operating time.

An example: You have a 250 mW transmitter needing 9VDC and drains 85 rnA.Youshoulduse an alkaline 9 volt battery because it has a current capacity of500 rnA, it will power theunit for more than five hours (500 mA/85 rna).

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Connect batteries in parallel to gain higher capacity or connect them in series to reach ahighervoltage. Use batteries ofthe same chemical makeup because different kinds deviatemarkedly from one another and will generally mess up your entire stacking scheme.

You can get almost any desired voltage by placingbatteries in series. The voltage ofa seriesbattery pack is obtained by multiplying the number of batteries by their voltage. Fourbatteries in series, each with 9 volts, will give you a battery pack of 36 volts.

+

+

Parallel battery stacking for longer operating time at the same voltage.

A general rule of thumb is for transmitters, use alkaline or lithium batteries because oftheir large capacity and long drainage rates. Use nickel-cadmium batteries for operationsthat need rechargeable cells. However, rechargeable batteries will limit operating timewhen compared to alkaline, mercury or lithium cells.

In general Lithium cells are the best choices but cost several times more than theircounterparts.

Always verify that you have inserted fresh batteries with correct polarity, then check theunit's operation.

120 VOLT POWER

You might have to use AC power ifthe transmitter will operate for a lengthy period in onesite. You can easily install a power regulator which adapts DC-powered units to takecurrentfrom 110VAC/60 Hz lines. Radio Shack sells a universal regulator that works quitewell in these applications.

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RECEIVERS

Your choice ofreceivers is by no means any less important than your choice oftransmitters.The usual selection is: A. To use a receiver designed to receive the exact transmitter youare using; this is especially true in a crystal controlled system. Receivers that tune only onechannel tend to be more sensitive (giving you longer range) than do tunablereceivers. B.An reOM type tunable, full spectrum stationaryreceiver. These units have a very sensitivefront end, cover the frequency of any transmitter you may wish to employ and have anadjustable bandwidth which you can narrow or widen for better intelligibility. Thedrawbacks with this type of unit include size and 120 VAC power requirements. C. A fullcoverage scanner, such as an ACE. Although usually not quite as sensitive as their non­portable cousins, modern scanners are good enough for most surveillance work.

Scanners also have adjustable bandwidths, positive channel lock-on and are completelyportable. I suggest you try using a scanner with your best transmitter before purchasinga more expensive matching receiver.

Any receiver must match your transmitter in operating frequency, modulation mode andbandwidth. Ifyou use a wideband receiver with a narrowband transmitter, heavy noisewill result. Ifyou use a narrowband receiverwith a wideband transmitter, heavy distortionwill occur.

You should cut or collapse/tune the antenna of the receiver to the carrier frequency of thetransmitter so it is more sensitive to that frequency than others in the spectrum.Remember that all frequency signals in free space will register on your antenna.

Antennas output the extremely faint signals they receive to the RF amplifier input. TheRF amplifier is tuned to boost the frequency of the transmitter more than any otherfrequency registering on the antenna. Undesired signals well away from the correct signalwill not be boosted in the amplifier. IF amplifier circuitry, explained below, rejectsfrequencies very close to the correct signal.

In most receivers the local oscillator generates an RF signal 21.4 MHz below or above theincoming frequency and mixes them together to create a new signal. Incoming RF carrierat 170 MHz mixes with the local oscillator signal at 148.4 MHz will make a new signal at21.4 MHz that modulates with the carrier's audio portion. Ifyou change the local oscillatorto 153.6 MHz, you would receive a carrier signal of175 because it makes the needed 21.4MHz.

The mixer circuitry generates an intermediate frequency (IF) of 21.4 MHz by combiningthe RF carrier from the RF amplifier output with the local oscillator output. IF amplifiercircuitryoperates at 21.4 MHz alone and rejects or reduce the power ofany otherfrequency.

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This important section performs the majority of gain and selection for the receiver.

Good receivers will often use narrow band IF amplifiers allowing only 5 KHz deviation orless from the 21.4 MHz central frequency. Modulation of this range gives good speechreproduction and automatically reduces background noise. Narrow band pass allows yourreceiver to choose between signals with extremely close frequencies. As you would expect,higher priced receivers tend to offer tighter band pass.

Output from the IF circuitry couples with the limiter's input. The limiter removesamplitude variations, or noise, from the IF signal. FM receivers are better than AMreceivers because of the noise-reducing quality of the limiter.

The limiter's output goes to the demodulator, which detects the audio portion and couplesit to the AF amplifier. The amplitude section amplifies the weak audio signal from thedemodulator until it is loud enough to drive a speaker, earphones, or a tape recorder.

Your receiver and transmittermustbe compatible in modulation, frequency andbandwidthor the surveillance system will not work.

Remember the receiver must exactly match frequencies or you will have no signal, and ifthe bandwidths are not the same you will encounter clipped, not understandable audio.

FM units reduce noise better as the input signal power rises. You can express noisereduction, referred to as quieting, as a ratio of RF input in microvolts to a quieting ratioin decibels (db). For example, your FM receiver could have a rating of 0.25 microvolts for20 db quieting. With such a device, RF signal at the antenna boosted from 0 to 0.25microvolts will cause background noise to decrease by a ratio ofl00 to 1, usually expressedas being minus 20 db.

Receiver Size

In the perfect surveillance situation you would not care about the size of your surveillancereceiver, but in real life you sometimes need a miniaturized unit to conceal on your bodyor in your briefcase. Small size does not have to mean low sensitivity, but it might meanyou will be unable to tune the receiver. Some pocket units have tuning controls for a fewset frequencies. Your audio output will generally go to earphones or directly to a taperecorder.

Ruby Electronics sells a nice, quite sensitive pocket receiver for use with their transmit­ters, as do a number oflaw enforcement suppliers and a Japanese company or two.

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Vibrations and shock can damage radio receivers. Protect the units by transporting themwith care in a proper carrying case when you travel between temporary listening posts.

For a moving listeningpost, use a vibration tested receiver, adapted for 12 VDC auto power.Increase range by mounting the antenna outside the vehicle and using a gain antenna ifpossible. In some "sensitive" neighborhoods a gain antenna may give an impression youdon't wish to convey, but most people will see it only as another car phone antenna.

Use receivers with the best sensitivity and selectivity ratings. Look for sensitivity to be onemicrovolt or less, with 0.5 to 0.1 available in ICOM type receivers. Sensitivity changes abit across bands in multiband units.

Law enforcement folks generally use VHF for surveillance. Selectivity here is rated interms of narrow band (plus or minus 5 KHz) usage. An example of good selectivity is abandwidth of -3 dB of plus or minus 7 KHz.

BANDS

Some receivers can tune a many frequencies or bands offrequencies. Law enforcement andtop civilian model surveillance receivers employ crystal controlled switching to select onlyone frequency.

A receiver is said to be selective when it can pick out one signal and reject all others. The. receiver tunes to one frequency and reduces the power any incoming frequency not

selected. The RF spectrum is clogged in big cities, with assigned frequencies very closetogether. Your receiver will operate under such conditions only ifit is highly selective, say-90 db, plus or minus 25 KHz. Your receiver will reject signals 25 KHz removed from itsselected frequency.

Sometimes stations broadcast on frequencies that your receiver's selectivity should reject,but still cause interference, known as "spurious response." The manufacturer makes thecircuitry attenuate spurious responses and lists them. Spurious signals will have to bemore than 80,000 times as strong as the receiver's selected signal before they can interferewith reception. Spurious responses are specified as more than 75 db below rated sensitiv­ity.

Frequency stability is stated along with temperature tolerance. Crystal controlled receiv­ers can be specified at 0.0005% (plus or minus 5 ppm), with a range of -30 degrees C to +60degrees C. A receiver rated at 0.0005% will not drift more than 5 Hz for every MHz. Pocket

34

receivers should be rated at plus or minus 0.0020, with a range of 0 degrees to 60 degreesC. Regular receivers should be plus or minus 0.0010, with a range of0 degrees to 55 degreesC.

Stability is an extremely important consideration if you are using a cheaper, non crystalcontrolled transmitter, less important but still a valid statistic in CC units.

How stable a tunable receiver is depends on the range ofits Automatic Frequency Control(AFC) circuitry. AFC range is usually plus or minus 80 KHz when released, plus or minus50 KHz when locked. A receiver with AFC locks onto any powerful signal plus or minus 50KHz of the correct signal and will not lose the signal unless it drifts at least plus or minus80 KHz .Most scanners will accomplish this, giving them the opportunity to "track"driftingtransmitters.

If you plan on monitoring the reception full time, you can always adjust the receiver tocompensate for drift, but ifyou use a dead LP the equipment must be accurate enough tolock on and stay there.

If your receiver is not equipped AFC, it is limited by its built-in frequency stability. Thisrating is connected to what temperature extremes it can operate under. An example ofgoodstability for receiver tuned to the 150 MHz band is plus or minus 50 KHz with atemperature range of 0 degrees to 40 degrees C.

Pocket receivers with earphones draw perhaps 300 mW of power and can operate for atleast 22 hours, while a big receiver with speakers will eat up at least 3 watts.

THE LISTENING POST· Placing the Receiver

The Listening Post is where the actual surveillance takes place. Most LP's are equippedwith a receiver, antenna, recorder, speaker, earphones, walkie talkie for communicatingwith outside agents, possibly a filter set up, back up receiver, etc. Carrying a mini receiverin your pocket with Walkman headphones running to your ear constitutes one type ofLP,but better results can be obtained by judicious planning.

An LP can be monitored by an agent manning the place 24 hours a day (which usuallyentails renting an apartment or motel room near the transmission site), may be mobile (avan is the best choice here) or may be totally automatic and stashed in the trunk of a caror other accessible site. An automatic LP must have an antenna, a receiver, a recorder andsome method ofturning the recorder on and offas not to waste tape when there is no audiopresent. Some recorders can have their variable VOX (voice operated relay) adjusted as to

35

work only when a certain level of audio comes from the receiver but it is a better bet toemploy a unit designed to do just this.

CAPRI ELECRONICS1238 Highway 160-BPOB 589Bayfield, CO 81122

Sells a very inexpensive interface that will start the recorder only when audio appears onthe receiver or scanner. This allows the agent to employ a fairly cheap scanner, goodantenna, Capri starter and a recorder in order to put a target area under 24 hoursurveillance.

Another unit designed for scanner/recorder unaided recording is available from:

BM!202 TullyProspect Heights, IL 60070

The BMI NiteLogger automatically records conversations from a scanner or receiver. It can he adjusted todisregard hum and distortion and functions with any tape recorder with remote capability. Under $75 forthe main component of an automatic LP.

36

As we will see in a moment, the correct long play recorder can capture hours and hours ofroom or phone conversation without a service call.

A brand new concept is now available from a couple of Japanese suppliers. This unitconsists ofan antenna and a receiver combined with a recorder and starter in one package,usually tuned to one of their transmitter frequencies. A nice set up for "instant" surveil­lance - place the transmitter, turn on the receiver unit and you're up and running.

Available from:

SUNMECHATRONICS CORP13-15-105AOII-ChomeAdachi-kuToyko,120Japan

This offers an inexpensive, ready-to-bug system that can be purchased off the shelf.

Well, the shelfis in Japan, mind you that's what the mail is for, right?

Often you can dramatically boost transmission range by increasing the height from whichyou broadcast or receive, or by transmitting over a large area of water. Ifhowever, heightdoes not improve your signal, by all means experiment with decreased elevation.

Always make note of potential interference sources. Stay away from high-voltage sourcessuch as neon signs, power substations or medical centers whose instruments give offdiathermy or X-rays.

Consider also the interference problems posed by elevators, steel reinforcements orstructures with reflective metal skins- semi-trailers, for example. Write down or draw thelocations ofinterfering structures that can be moved, and correlate their movements withany changes you detect in interference.

Place receivers with non-detachable antennas in hot spots for signals at the same time lookfor and note some alternate hot spot sites in case your receiver experiences loss ordegradation of signal because of changes in the environment.

37

Basically the idea is that you must place the receiver in a strong signal area. Point yourreceiving antenna accordingly if the transmissions come from a directional antenna.

Locate your antenna in the highest possible site ifit can be detached from the receiver. Ifyou need to be prepared to receive through different antennas, couple them to the unit witha coaxial switch. Orient the antennas and match their impedance to the receiver.

KITS

A good technique for monitoring and recording audio broadcast by RF transmitters is touse portable receiving/recording kits. Make sure the systems are portable, so you canemploy them at any listening post.

A kit is usually set into a small briefcase with a cassette tape recorder. The unit turns onwhenever it picks up a signal from the receiver, so you can let it operate withoutsupervision. Power comes from batteries, hopefully AC-rechargeable, it should have abuilt-in antenna, receiver and transmitter. You can get, or make, a kit customized for anyoperation.

Law enforcement "kits" from many suppliers including emx, AID, etc. Civilian kits from:

SPYTECH INDUSTRIESPOB 1937Point Roberts, WA 98281

ANTENNAS

Antennas are the most often overlooked and undervalued component of a surveillanceoperation, yet they can make the difference between a successful bugging and a tape fullof noise.

Transmitting antennas are harder to modify because of the necessity of covert operation.Receiving antennas can, and should, be "fine tuned" to provide maximum signal.

Let's look at some factors affecting antenna selection, including gain, bandwidth, physicalsize, directivity and polarization, and how they match up with different kinds ofantennas,namely yagi, slotted array, corner reflectors, helical, skirted dipoles and collinear skirteddipoles.

38

This section is designed to give you an overview 80 you will be able to pick the right antennafor any surveillance job.

These elements apply to both transmitting and receiving antennas:

Gain is the ratio of input power divided into output power, expressed by a ratio or indecibels.

Amplifiers are active and take power from a source and increase it. Antennas are passive,made from tubes, plates and metal rods. We get antenna gain by redirecting its powertoward one route and adding power taken from another route.

Antenna gain is a measure derived from comparing the antenna to an isotropic (equal fromall directions, no gain) antenna, with the resulting gain figure measured in dEL

Radiation from a real antenna cannot have the same intensity in every angle. Realantennas can have gain in one or more directions, and loss in others when you comparethem to isotropics.

The gain of a regular half wave dipole is 2.5 dBL You get gain by rechanneling powerperpendicular to the antenna's line. Energy does not radiate from the antenna's tips.

To boost gain at a particular frequency, increase the antenna's length or size. The biggerthe antenna, the more RF power it can capture. Frequency affects how large your antennaneeds to be. The size of antennas with the same gain working at 400 MHz and 800 MHzwill vary greatly.

Most antennas mounted on miniature transmitters utilize quarter wavelength elementsmade from wire or perhaps a dipole fashioned from two elements both about one quarterwavelength. The constricted space containing the antenna requires alterations in theelements' length so they electrically match the selected frequency. The alterations reducethe element's length compared to their theoretical length, to correct for being in a limitedspace.

To choose the best antenna length in feet, divide the number 234 by the frequency in MHz.

Consider how directional your antenna is, because you get gain by rechanneling energyacross the antenna. When your receiver is moving, say in a car, the transmitter needs tobroadcast a signal omnidirectionally in the horizontal plane, because the transmitter andreceiver are separated by a changing angle. When the receiver and transmitter stay in oneplace, your antenna can be extremely directional.

39

Use an omnidirectional antenna, such as a vertical halfwave dipole, ifyou need a completecircle pattern. If such a setup requires increased gain, just stack another dipole on theoriginal, making your setup collinear.

Your gainincreases when the antenna is more directional. Increased gain lets you transmitacross a given distance with less power, or gain more distance with the same power.

Some antennas actually increase the signal strengthby altering the basic circularpattern.Vertical antennas normally broadcast equally strong signals in a circle. But if the signalincreases power more to the East than to the West, the antenna would be directional,favoring the East for its directional gain.

Antennas can also increase gain horizontally by squashing radiated power near the top soits pattern is more horizontal. Directional antennas canbe receivingor transmitting types.All that matters is the signal transmits to, or is received from the correct direction. Again,this is usually easier to accomplish with the receiving antenna than it is with thetransmitting antenna.

Antenna gain is measured in decibels. For example, a 3 db gain antenna multiples thetransmitter's range as though you had doubled its power. Most energy radiates fromantennas at 90 degree angles to the element, and the least amount of energy comes fromeither end, making most antennas somewhat directional.

Transmitting antennas radiate an electromagneticwave, consisting ofan electric field anda magnetic field. An electromagnetic wave is said to be polarized in the direction of itselectric field.

Vertical dipole antennas are vertically polarized. You should be concerned with matchingthe polarization of signal and of the receiver's antenna. You will lose about 20 dB ifyourantenna is at a right angle to the correct polarization.

You might use an antenna that broadcasts a signal with circular polarization. Thepolarization of the signal rotates clockwise or counterclockwise while the signal moves.Make sure you match rotation direction if you use two circular polarized antennas.

You can mix circularand linearpolarization, butyou will lose about 3 dBin gain. Youwouldneed both polarizations if transmitter is subject to movement. If the transmitter hangsfrom a balloon in the sky and rotates along the up and down axis, you will be unable toreceive the weak broadcasts from its antenna's end with a vertical dipole, nor with ahorizontal dipole due to rotation.

40

A radio wave travelling through space keeps its original polarization which was set by theantenna.Ground structures and changesin landscape can change how the wave is orientedso you cannot predict the final angle of polarization. A common mistake is to assume thatbecause a signal left the antenna horizontally polarized, it will arrive at your receiver stillhorizontally polarized. For the best recel)tion. eXl)eriment with your receiyini: antenna'spolarization.

Radio signals 30 MHz or lower travel far by bouncing from the ionosphere back to earthor moving across the ground losing hardly any power. However, you use higher frequenciesfor intelligence transmissions, and these are capable of moving only in straights line-of­sight paths. VHF and UHF signals moving along these paths lose power. Any brick,concrete or wood structures can change the patterns of signals moving through them.Structures made ofmeta! reflect or absorb VHF and UHF signals in an unpredictable waydetermined by the signal's arrivingangle andfrequency, and by the structure's dimensions.

When a radio wave reflects and rereflects through such a landscapes it reaches the receiverantenna by many paths. Ifthe rereflected signals come in phase with the original line-of­site transmission they strengthen one another, this is a good reception area. Ifthey arriveout of phase with the first signal and cancel one another, the area is not a good receptionarea. VHF and UHF wavelengths are short enough so that a listening post in a small roomcan have many good and bad reception areas. Often you will receive only reflected signals,the direct ones being blocked.

An antenna is more directional as its gain increases. You can make the antenna morefrequency-selective to increase gain. Do not use extremely selective antennas when youwork with wide band FM signals, for example FM video. Your receiver or transmittingantenna (low VSWR) needs to match all frequencies it uses.

Youcan get wide band width with large-diameterelements. Alsoyou can broaden responseby varying the lengths of elements. Directivity, size, bandwidth and gain all effect eachother, and your antenna design will have to trade one aspect for another.

The smallest omnidirectional antenna that gives 2.5 dBi gain is the skirted half-wavedipole. For an extra 3 dB ofomnidirectional gain, use a collinear skirted dipoleswhich addsone half-wavelength to the length, and lowers the angle of radiation. Ifyou use four totalhalf-wavelength dipoles you attain 8.5 dBi of omnidirectional gain.

Another way to get 8.5 dBi of gain is to employ a slotted array, which redirects the wavepattern forward. Hardly any signal broadcasts from the back of the slotted array. Makesure you matchpolarizations when you use a slotted array with a skirted dipole. Youmightneed to rotate the slotted array one 90 degrees to match polarization, because it does notlook like a regular antenna.

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To reach gain more than 8.5 dEi, use a wide bandwidth yagi design. Like the slotted array,the yagi redirects the wave in one direction. It uses at least one reflector and director, thespacing and length of determining gain and beam width. Remember, however that highgain antennas have lower bandwidth and lessen your system's performance.

Yagi style antennas provide extremely good signal gain by making the reception pattern very directional.Note one antenna is vertically polarized while the other is horizontal.

Ifyou want circular polarization, use helical antennas, which come as high gain, extremelydirectional, or as low gain types, but usually have a very broad bandwidth.

Your system performance will vary, depending on both the transmitting and the receivingantenna. Select and apply your equipment with care in order to get the best performance.Make sure you match receiver and transmitter when you employ circular linear polariza­tion. Whenbeamwidth is yourhighest concern, use as much gain as the system can handle.

When you use 30 MHz signals or higher, your operating range along the earth' surface isreduced because this range is line-of-sight. If the transmitter and receiver antennas arefive feet above the ground, your range will only be three miles, no matter how much poweryou pump into the system. Therefore, you should place your antennas in the highestposition possible.

Move the antenna to different sites until you fmd a few good points for signal reception.Mark each site for potential later use, and choose the best for the job at hand. You should

42

rotate the antenna and move it until you find the strongest signal. Use the antenna in thatposition. Ifpossible use a device known as a SWR (Standing Wave Ratio) meter on yourunits to "tune" the antenna for the least SWR. these meters are available at Radio Shackor Ham outlets and help channel maximum signal to the antenna.

When you put an antenna on a roof, you should probably use antenna extension cable. UseRG-58U cable for 50-feet lengths or less, and RG-8U for longer lengths. Ifyou use 100 feetofRG-58U you will lose 4.6 db at 100 MHz, and if you use 100 feet ofRF-8U you will lose2.2 db at 100 MHz.

FILTERS

Normally, you should record everything because certain aspects of the audio may becomeclearer after several replays and also because you can apply filters to clean up variousportions of the material to enhance intelligibility.

You can use an audio filter to reduce the power ofcertain frequencies. To reduce the powerof one frequency or one band of frequencies without attenuating frequencies nearby isdesirable, but technically impractical.

Think of audio filters as excellent tone controls with selective circuitry that reduces thepower of frequencies or entire frequency ranges. One kind of filter is integral to theamplifier and boosts selected frequencies while decreasing unwanted ones.

This is active filtering. Passive filtering serves only to reduce the power of unwantedfrequencies and cannot amplify the correct one.

High pass filters allow all frequencies higher than a certain programmable level to proceedthrough, and reduce the power ofall frequencies below.You use a high pass filter wheneveryou operate the bass control on your music system at home.

Low pass filters allow only frequencies lower than the set level through, and reduce thepower of any above. This filter is comparable to the treble control on your stereo.

A high pass filter set for a cutoffof400 Hz reduces the power of all frequencies under 400Hz.

Cutoff is the point in a filter where all frequencies either too high or too low are highlysuppressed (minus 3 dB)- and not actually cut offper se. The filter evenly reduces powerin frequencies through tile frequencies one or more octaves from the tile cutoff.

43

Systems can perform high and low pass filtering individually or at the same time. You canvary the cutoffpoints for these filters, squeezing or expanding the range offrequencies youwish to leave alone.

Parametric filters, long popular in music recording applications have infinitely variablelimits in both frequencies and attack slopes (bandwidths). Parametrics were the mostuseful types offilters until recently, with the advent ofcomputer enhancement, especiallyhome PC based enhancement, sound recreation has moved into another dimension.

Ifyou try to use high and low pass filters to eliminate interference in the voice range, youwould lose too much wanted sound. In this case, ifthe tile interference is one frequency ora closely packed group of them, use a notch (or "dip") filter, which can easily reduce powerover a small band of frequencies.

Notch filters can have variable or fixed operating frequencies. Use a group of fixed filtersto process bands near each other. Ifthe filter is variable, you can probably adjust its depthalso. For your purposes, you will find a depth or amount of attenuation of 20 dB (100:1)quite acceptable.

You should prefer using the more flexible variable notch filter over the fixed type. You willget less distortion and amplifier noise with a variable type because all the notch cuts canbe made in one time. Ifyou use high pass, low pass and notch filtering on one recording youwill highly reduce noise.

An audio processor or parametric filter can reduce the power of unwanted sounds above4 KHz and below 600 Hz. Load the unfiltered tape recording into the unit it was recordedon. Couple the recorder's output to the processor's input and plug headphones into theprocessor's output. Then you can monitor the tapewhile making precise adjustments to thehigh and low pass cut off frequencies, eliminating noise more effectively.

Computer based processing is almost magic. It does not "filter" sound but rather analyzessound.

The best PC based processing system around, I think, is available from:

SONIC SOLUTIONS1891 E Francisco BlvdSan Rafael, CA 94901

makes a Macintosh based digital processing workstation that has a number of uses inforensic sound. it used a form of artificial intelligence to remove noise from surveillance

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FL2/A AUTO-NOTCHMODULE

Model Fl2/A is a ready as­sembled andfullytested auto­matic notch filter module in­tended primarily to enable FL2 users to upgrade toModel FL3, It can also be built into other equipment.

ModelFL2/Ascansthe audiospectrum from 350 Hzto3.5 kHz looking for continuous tones. When it detectsone it automatically notches it out. The notchdepth isbetter than 40 db at 1 kHz, and acquisition time is~pi~lIy 1se~on? It comescomplete withcomprehen­sive installation Instructions, mounting hardware andnewfront panel to convertexisting FL2sto FL3s.

ModelFL2JA requires a power supplyof 10 to 16 voltsDC@40mA. Normallythiswill comefromthemainunit.

ANFAUTOMATICNOTCH FILTER

ModelFL3connectsin serieswiththe loudspeaker leadfrom the receiverand by usingstate of the art technol­ogy, achieves remarkable versatility.

Thetwelve polesof turnablefilteringcan be usedin sixdifferentwayswhichwill assistyou to; digdownintotheQRM andhearthatweakSSBOX; listento CWthatyoudidn't evenknowwasthere;pull RTTYout of the noise;and remove offensive whistles and heterodynes fromany modeof transmission.

FL3MULTIMODEAUDIOFILTERWITH AUTO-NOTCH

Whether you are an amateur or professional and nomatterwhich rig you own, the overcrowding on today'sHF bandscan spoil your reception. Oatong's MODELFL3AUDIOFILTER isprobablythebestavailable in thew?rld today and. can enhanceyour enjoyment by ena­blingyou to realisethe full potentia) of your receiver.

Theconnection isquitesimple,butthedifference inper­formance is outstanding.

ModelFL3has two notchfilters. One is manuallyoper­ated, the other (an additional four poles of filtering) iscompletely automatic andoontinually searches forwhisttesand heterodynes and removes them in a secondor so.Combine thiswithcompletely independentvariablehighand low pass filtering and you havea truly remarkableaudiofilter. InfactModelFL3simulates theeffectoffullyvariable IF selectivity with pass-band edges that aresteeper than most crystal filters, and can be usedwithalmostany receiverold or new.

ModelFL3requiresa powersupplyof10to 18voltsDCat 150mA and comescompletewith connecting leads.

Some examples oflow endfilters from Datong Electronics

Thevaluefor money. standaloneautomaticnotchfilterthat doublesas a CWfilter. ModelANF is small in sizebut neat in looksand big in performance.

Simply connect model ANF in series with the loud­speakerleadofyour receiver andyou cansaygoodbyeto heterodynes, whistles and other steady tones thatoftenmake listening onthecrowdedamateurandshortwave bandshardwork. They will vanishautomaticallyas the ANF notches them out while at the same timeshowing thefrequencyof theoffending interference ona bargraph LED display.

Atthe pushofabuttonmodelANFbecomesagoodCWfilter eliminating all but the signal you want to hear.Manual orautomatic operation in notch and peak modes,plus automatic frequency control, make Model ANFextremelyversatileand easy to use.

A power supply of 10 to 16 volts DC @ 100 rnA isrequired. ModelANFis supplied withconnecting leads.

4S

recordings that makes normal filtering look like a model T Ford standing next to aLamborghini Diablo.

I have heard this system take a mess ofrumblings. pops. crackles and static and strip themlike layers from an onion toproduce a relativelyclean, complete understandable conversation.

This system is known as NO NOISE and it works like the name infers it would. It plugsdirectly into a Mac and lets the operator use a number of separate tools. like Fouriertransforms. automatic de-clicking. anti-clipping, de-hissing, etc.

The system let's the operator watch and control the entire de-noising (un-noising?) processmuch like running a video game. Much of the operation can be run as a backgroundoperation or each individual component can be operator attacked for maximum effect.

This system is priced to be affordable for medium to large law enforcement departmentsand may be a bit out ofreach for most private organizations, butvarious NO NOISE ownerswill preform surveillance tape enhancement for a fee.

Needless to point out, you musthave somethingon a tape in order to use tape enhancement.Record everything!

Low end (cost wise) filters can be purchased from electronics outlets or surveillancesuppliers. Parametric filters can be purchased from audio suppliers including:

DATONG ELECTRONICSClayton Wood CloseWest Park, Leeds LS16 6QEEngland

RECORDERS

or: SIG OPS GROUPPOB 4882Poughkeepsie. NY 12602

The recorder is the heart of any audio system but is often the weakest link in the chain. Itis desirable. in most cases. to record as much intelligence on a single side ofa single cassetteas possible so not to have to visit the LP (or hidden recorder) more than necessary to changethe tape.

The accepted method to do this is to employ a modified, "long play" recorder. the problemis that most so called "long play" recorders simply change the size of the capstan in orderto move the tape through at a slower speed. You can do this yourselfby wrapping frictiontape or a rubber band around the rubber doughnut in the capstan drive. This modification

46

is less than satisfactory as it produces unstable speeds, wow, flutter a high wear rate anddistorted audio.

Look for a recorder that has been modified with a positive electronic speed control lock toprovide 8 or even 10 hours of recording on a single cassette (4 or 5 on a side) along with apositive speed control lock on the motor and a specially designed circuit that compensatesfor the change in audio when operating at a slower speed.

Reduced speeds do change the audio andifyou need to decode touch tones or just want clearconversation make certain your long play unit has an effective compensation circuitinstalled.

The larger the basic, unmodified recorder is, the better chance the modified version will beof acceptable quality. Most surveillance suppliers take a standard size Sony or Panasonicunit which gives just enough space for politically correct mods.

If you want a smaller, microcassette version (good for body applications) do not expect toget as long of a record time (maybe 2 hours per side) and little or no audio compensation.

In the other direction, ifyou can afford an upgrade in both size and price it is possible tostart offwith a more professional, sturdy recording unit which allows bettermodifications.These professional recorders also offer more rugged drives and other features not found onthe smaller units.

Effective modified recorders are sold by:

INTELLIGENCE INCORPORATED2228 S EI Camino RealSan Mateo, CA 94403

or: OMNICRON ELECTRONICS581 Liberty HighwayBox 623Putnam, CT 06260

or: SHERWOOD COMMUNICATIONS ASSOCIATESPOB 535Southampton, PA 18966

47

GENERALOMNICRON"VLR" recorders are professional voice loggers designed to pro­

vide you with completedocumentationof your important telephoneconversations,two-way radio messages, or dictation, They have special features which allowvirtually unlimited use in a wide range of applications. with top performance andminimal maintenance.

Built-in voice activation circu itry expands the recording time by automaticallystopping the recorder between conversations. Model VLR-1 runsat the standardcassette speed allowing you to record and playback tapes which are compatiblewith recorders that do not have slow speed capability.

Advanced slow speed drive circuits in the VLR·4 and VLR·8 recorders expandthe recording time even further to provide 8 or 16 hours ot solid talk time on eachcassette tape. The VLR·4 provides four times the unattended recording andplayback time. It packs 8 hOurs of conversation on each MLC·120 cassette tape.ThesuperslowspeedVLR-8runs at~ speedfor 16 hourspertapewith little lossoffidelity (8 hours per side with an MLC-120 cassette).

VLR recorders with the "CT" Clock Track option (VLR-1CT. VLR·4CT, andVLR·8CT) are designed for use with the Omnicron TCC·14 Talking Ctock/Ca­lendar. They have a second track for recording the verbal lime and dateannouncements provided by the clock. Whenplaying back the recorded conver­sations. simply switch to the Time Track and you will know exactly when therecording was made. One Talking Clock can provide time and date announce­ments for over 50 recorders.

FEATURESVLR.1.VLA·4, &V\.A.,VOICEACTIVATED RECORDING - withadjustablerecord level,activatesensi·

tivity, and turn-ott delay.

RECORO LEVELrNDICA10R

ALC SWITCH(TiME 1 AACKSWITCH ONUNITS WITH

"c r OPTIONl

ALARM - beeps when the cassette needs to be changed, or if the recorder isturned off either accidentally or by built-in au-modemotionsensingcircuit.Thetape drive automatically turnsoff and sounds the alarm if thetape stops when itshould be moving in record, play, tast-torward, or fast-rewind.

MONITORWHIL£RECORDING -letsyou listento conversationswhile they arebeing recorded, through the built·in speaker, through either of the two '4"headphone jacks (one mutes the built-in speaker, the other does not), orthrough the 'A" external speaker jaCk(4 Ohm).

CUEANDREVIEW - for rapidly finding and repeating recorded messages.AUTOMATIC RECORD LEVEL CONTROL - prevents overload on strong sig­

nals.AUTOMATIC END·OF·TAPE SHUT·OFF - in record, play. fast-forward, and

fast-rewind.AUTOMATIC BATTERY CHARGING - for optional rechargeable batteries.unit

automatically switches 10 battery power if external AC power is lost.MONITOR & ALARM ON/OFF SWITCHESINPUT/OUTPUT JACKS - microphone, remote record on/off , auxiliary audio

input, remote speaker, two headphone jacks, and Talking Time Clock (CToption only).

BUILT·IN ElECTRETMICROPHONEROTARY VOLUME & TONECONTROLSDIGITAL INDEX COUNTER WITHRESET - conforms to 2X ANSI standards.ACBIASRECORDING - lor optimum voice frequency recordings.DESIGNED FORCONTINUOUS DISPATCH CENTER OPERATION.EASILY SELF INSTALLED - with or withoutdirect electrical connection.COMPATIBLE WITHTHEFULL UNE OF OMNICRON ACCESSORIES.

ALARM ON /O FFSWITCH

STOP.EJECT KEY

SPECIFICATIONS

POWER: 120 VAC50/60 Hz,8 watts, six "C" cell batteries, or optional recharge­able batterypack (RBC·6).

SIZE: 11'/,"L x 1OWW x3'12"H. S'12 lbs,INPUTS: Microphone, 2 k ohms, -70 dB

Auxiliary. 200 k ohms. ·20 dBClock, 600 ohms, ·10 dB

AUDIO OUTPUT: 1 WattSIGNAL TONOISERATIO IA.welghted): VLR· I =50 dB,VLR·4=42dB,VLR·8 =

34 dB.TAPE SPEED: VLR·l =1-7/8 I.P.S., VLR-4 =1S/32 I.P.S.,VLR·8 =15/64I.P.S.FREQUENCY RESPONSE: VLR·1 = 125 Hzto 10KHz, VLR-4 = 125Hzto 6 KHz,

VLR·6 = 125 Hz to 3 KHz.

TAPE SIZE:StandardCompact Audio CassetteRECORD SYSTEM: Hall Track ('A track with "CT" option). AC bias.

ERASE SYSTEM: DC

MAXIMUM RECORDING TIME:VLR-1 = 1 hour per side (MLC-120) at 1-7/8 I.P.S.VLR-4 = 4 hours per side (MLC-120) at IS/32I.P.S.VLR-8 = 8 hours per side (MLC-120) at 1S/64 I.P.S.

BUILT·IN SPEAKER: 3" x S".Each VLR recorder comes with an MLC-120 cassette tape. attached AC powercord With bullt-m storage case. owner's manual, and a limited 90 day warranty.Specificafions are subject to change without nolice.

48

CELLULAR PHONES

As most sophisticated surveillance folks realizes cellular phones, far from beingimpossibleto monitors are quite eavesdropper friendly. BOOK II - HOW TO GET ANYTHING ONANYBODYis still the best source for a complete run down on the operating concepts andintercept possibilities of cellular telephones.

It's also a good idea to peruse both Bill cheek's and Tom Kneitel's books from:

CRB RESEARCHPOB56Commack, NY 11725

One recent breakthrough is the development of a reasonably priced (about $6K) briefcasesized cellular monitoring system. The CELLMATE includes an internal antennas taperecorder, dialed number recorder, internal battery etc.

You simply dial in the number of the cellular to be monitored and the unit does the rest.

CELLMATETech Support Systems1203 Nonnandy WaySanta Clara, CA 95050

A very nice cellular gain antenna (yagi style) that offers a healthy 15 DBi gain on the 800MHz band is available from:

ELECTRON PROCESSING INC.POB68Cedars MI 49621

This antenna will si@ificantly improve the range and directional capabilities of mostmonitoring systems including ICOMsssscanners and the enhanced OPTOELECTRONICSfrequency counter system described in BOOK II • HOW TO GET ANYTHING ONANYBODY.

49

BRUSHED ALUMINUMHALUBURTON CASE

- - 8- DTMF DECODERAND DISPLAY

MODlnEDPANASONIC

PHONE

---t--It

J

MARANTZRECORDER

FORSALETOQUALUnEDBUTERSONLT

CELLMATETS5-10oo CELLULAR RADIO MONITORING SYSTEM

CeUmate is a sophisticated single voice channel, real time, cellular radio monitoring system. It is built into analuminum carrying case and includes a DTMF decoder and display, and a professional quality Marantz taperecorder.

Cellmate is designed for ease of use in the field with simplified commands that make one handed operationpossible . It automatically changes frequency to follow the target phone as it changes from one cell to another.Manual resetting is not necessary.

FEATURESo Operates both in general monitoring mode, and targets specific phones by number.o Has excellent audio quality.o The DTMF decoder stores up to 32 digits, which can be scrolled through the 8 digit display.o The modified Panasonic phone is removable, and can be used as a normal cellular phone.D The display shows target phone number, channel number, and Cellmate mode.o Operates with the built in, or an optional external, antenna.o Supplied with a battery charger and a cigarette lighter adapter and cables .D European TACS 900 model available.

50

TELEPHONE SURVEILLANCE

This report is not designed to be a complete study of electronic telephone surveillance simplybecause of the complexity of the SUbject. Intelligence Incorporated publishes a complete guideto practical telephone eavesdropping, and I would also suggest you consult our manual oncountermeasures for more specific telephone eavesdropping tips, but let's take a look at somepractical methods for both residence and office phone systems.

The commonest telephone tap is the auto start recorder that is placed in series or in parallelwith the tip and ring (red and green) wires in any particulartelephone system. The recorder itselfcan activate the recording process, being coupled to the phone lines (across them) by a smallcapacitor between the recorder and the phone line. This system blocks any DC but lets theaudio pass into the recorder's microphone jack. It usually also requires a resistor to pad downthe level of the incoming audio to avoid distortion and bring the level within range of therecorder's VOX adjustment.

Once the line is hooked across both the red and the green wires you simply adjust the VOX levelof the recorder to start the recorder when audio is present. This can also be accomplished byutilizing a small transformer and a capacitor on one lead. The secondary winding of thetransformer goes directly into the tape recorder.

The transformer-plus-capacitor arrangement is a bit safer because of the smoother chargingand discharging of the cap. making it less likely to show up on a low level (VOM based)countermeasures search.

The capacitor in either system averages about .001 microfarads.

Either of these systems works well when attached to a extended play recorder with anadjustable VOX starter. The operator simply hides the recorder in the garage, attic, or outsideof the building. using the inside wiring or the drop wire for the audio path. He simply needs tocome by every couple of days to pick up and replace the tape and change the recorder'sbatteries (recorders use very little power when on VOX, the draw will be dependent on theamount of conversation that actually gets taped).

This is probably the most common system in "significant other" tapping .

The next logical system would entail the use of a drop out relay, or ''telephone starter." Theseunits sense the voltage drop in a telephone system when a receiver is lifted off hook and thenstart a recorder, via the remote start jack. passing the audio into the mic input.

51

Drop outs come in two flavors: series and parallel. Series units must be hooked in series withall of the telephone instruments in order to record conversations on any line. If a series unit islocated on the wiring from only one telephone, that instrument's audio is allthatwill be recorded.

Because of this, the logical placement of a series starter is after all the individual phone linescome together. Examples of this would be at the outside drop wire, the outside protector blockor the common wire all extensions merge into.

Remember, voice activated (as opposed to voltage sensitive) units can be installed anywherein the network, including on an extension phone line. inside any handy connector block, andso on.

Parallel drop-outs also exist. These units can also be installed anywhere along the network andautomatically start and record conversations on any phone in the system.

Parallel-starters are law enforcement favorites because you can cover the entire building (onany single phone line) with a single installation. Parallel starters need to be installed physicallycloserto the actual phone instruments than do series starters. Better units feature a very highinput impedance (10-30 million ohms) in order to make them a bit more impervious tocountermeasures searches.

Most general surveillance companies such as Intelligence Incorporated, Sherwood, AMC, etc.sell acceptable phone starters as do many law enforcement suppliers. It should be noted manyso called "law enforcement" parallel devices are easier to detect due to low input impedancethan are their cheap civilian cousins.

Radio Shack makes both a series and a parallel recorder starter that work quite well. The RadioShack units feature telco modular plugs that snap into wall jacks since they are legal taps andnot designed to be hidden, but both units work well and have a fairly high input impedance.

RF Taps

Next in the logical progression of telephone surveillance is the use of a radio frequency tap toRadio transmitters offer the same flexibility in telephone tapping operations as they do in roomsurveillance. A successful RF tap can be manned or operated in a fully automatic conditionsubject to the same conditions as a room transmitter, i.e., the signal can be transmitted directlyto a close by LP, monitored by a crystal controlled receiver, an ICOM, or even a scannerequipped with the proper antenna for optimum reception.

The LP can be stashed in an apartment or a vehicle or a repeater can be employed to extendthe useful range of the tap to a distant, and more convenient, LP.

52

Tap transmitters come in free running and crystal controlled versions, and, as with roomtransmitters, the more dependable and the more expensive are the CC versions. these are soldby RUBY ELECTRONICS, SHERWOOD, C~A.Z and a couple of the Japanese supplierspreviously detailed.

The other consideration in an RF tap is whether it be series or parallel. Series units leech theirpower from the telephone line itself meaning they never need battery changes but that theiroutput power is limited by the amount of current they can draw without tripping telco relays.

Series units are also easierto find with simple voltage/current measurements than are parallelunits. Series units require the operator to break on side of the phone line and install the unit aspart of the line itself.

Like their hardwire counterparts series units should be installed after the various telephoneswhere all lines merge into one output. A favorite place for series transmitters is at the outsideprotector block, as many transmitters are small enough to fit inside this block, installationrequires no breaking and entering and takes only a minute or so of the agent's time.

Series units can also be installed further down the line, at B boxes orin rubber installation bootslocated on poles.

Parallel taps. or bridging taps as they are known, go across the tip and ring, require their ownpower supply. normally have a separate antenna (as opposed to series units that use the phonewire), are more difficult to locate, can be installed anywhere in the loop and will broadcast allconversation on any unit in the system.

Amateurs connect bridge taps in, or near the target phone (wall connecting blocks are a favoriteplace); pro's install them at B boxes. multiples, or appearances several blocks from the originaltarget. Any parallel tap is by nature hard to locate because it does not greatly affect the DCcurrent flow in the telephone circuit.

One great trick is to bury a bridge tap along with a long lasting cascaded battery supply and arecorder near a phone distribution cable and dig it up every week or so so a a complete recordof the target's calls.

Very difficult to find ...

More exotic, although. not necessarily more difficult taps, can be accomplished by such tricksas splits where the professional eavesdropper combines the individual wires in a 25 wiredistribution cable in such a fashion that conversation can be pulled of of the target wires withvery little chance of discovery.

53

The split, in effect, promotes cross talk and lifts the target audio out of the wires with a powerfulamplifier.

The same principle is in effect with the use of an induction tap. Although the audio is very lowlevel, the tap is non existent to most electronic surveys. These sophisticated tapping methodsare too involvedtogointo here but will be covered in HANDS·ONTELEPHONE SURVEILLANCE.

SUMMARY:

The three most important elements in the effective use of eavesdropping equipment areplanning, control and follow through.

You will get optimum performance from your equipment by carefully orchestrating thelocation and events of surveillance.

Avoid conducting surveillance in a moving car because the engine's noisy interference candestroy your audio quality. Reduce electrical noise of any kind. Stay away from metalbuildings, industrial zones or power transmission sites. Test your equipment where it willbe employed so you can find the best area for a listening post.

Choose the most quiet meeting place possible. Do not, for example, select a bar where noiseor music will interfere with surveillance. Allow for the receiver to be in close proximity tothe transmitter. Carry plenty of fresh batteries and throw a battery away no matter howbriefly you have employed it. And, have the transmitter so you can easily turn it on and off,or change its batteries.

When you conceal a device on your person, manipulate events and environment so you andthe suspect are as close as possible to each other, and so his or her movements arerestricted. Arrange for undercover meetings to be held out in the open for the besttransmission reception. And when you wear a body transmitter be sure your clothingadequately conceals the equipment.

54