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Intercept equipment
Receivers, direction finders, TSCM, etc.

This page shows some equipment that was used during or after WWII to find clandestine radio stations and intercept enemy radio traffic. Much of this equipment uses Morse Code for the transmission of data. Click any of the images below for a full description of each device. Please note that the list is by no means complete. If you have any further information to offer, or better: if you have any surplus equipment available for the Crypto Museum collection, please contact us.

Also note that the title 'Intercept equipment' doesn't fully cover the nature of this section, but we just couldn't find a better one. This chapter includes equipment to locate clandestine radio stations, intercept spy communication (spy sets and surveillance radios) and find listening devices (bugs). A common name for the latter is TSCM (Technical Surveillance Counter-Measures) [1].

 Index of intercept equipment

Direction Finders
Telefunken E-383-N (EP2a) LW radio direction finder
GPO interference investigation receiver WT No. 11
GPO Receiver (UK)
German Gürtelpeiler, used during WWII
Portable radio direction finder (US, 1942)
Mobile radio direction finder DBF-1
DAB and DAB-3 radio direction finder (US)
FH-4 HF/DF (huff-duff) high frequency direction finder
Wilhelm Quante St.Sg.52 (Germany)
Telefunken PE-484 Kleinstpeilempfänger
RZ-301 Pospisil (CZ)
Russian R11-PA valve-based body-wearable direction finder
WWI portable direction finder in suitcase
Belgian post-war version of the UK Type 36/1 (MCR-1), made by MBLE (Philips)
EM-038-B French binaural aperiodic intercept receiver in suitcase
Soyka (USSR)
Filin (USSR)
Sinitsa (USSR)
Kopchik aperiodic surveillance detection receiver
Czechoslovak MRP-4 (Barabara) radar locator
Radio Direction Finder for 121.5 MHz distress beacons
Nahfeldausforschungsgerät (near-field direction finder) used by the Austrian authorities
OAR ADF-940 automatic direction finder for 27 MHz band
HRR-26 homing system used by the CIA
Bendix ADF-T-12-C automatic direction finder for LF/MF
TAIYO TD-L1706 direction finder
Sadelco FS-3 field strength meter
NRP field strength indicator with built-in frequency counter
Datong DF-5 direction finder
Second generation beacon D-903
PR-100 Portable Digital Receiver
LOCATE - spectrum monitoring system
 About direction finding

Intercept receivers
National HRO receivers
RCA AR-88 receiver
Hallicrafters SX-28 Super Skyrider receiver
Siemens R-II (R2) Abwehr receiver
Siemens R-IV (R4) Abwehr receiver
OSS (CIA) aperiodic receiver SSR-201
CIA VHF intercept receiver SRR-4
CIA VHF intercept receiver SRR-5
SRR-8 surveillance receiver 30-1000 MHz (1963)
EM-038-B French binaural aperiodic intercept receiver in suitcase
ACL SR-209 (SRR-23) HF/VHF/UHF/SHF surveillance receiver
SRR-52 listening post receiver
SRR-56 listening post receiver
Modular surveillance receiver for RP and DP masked bugs
Improved modular surveillance receiver (vertical model)
Improved modular surveillance receiver (horizontal model)
CIA surveillance receiver SSR-100
SRR-145 down-converter
SRR-153 surveillance receiver
Pristroj UHF 465 MHz intercept receiver, used for monitoring French counter-espionage
2170 Intercept Receiver as used by the Stasi in the former DDR
Minilock 6900 Programmable Precision Measurement Receiver
Minilock 6910 Programmable Precision Measurement Receiver
Rohde & Schwarz EB-100 portable surveillance receiver
Rohde & Schwarz EB-200 Monitoring Receiver 10 kHz - 3 GHz
Czechoslovakian VHF or UHF bug receiver
Special receiver for BODIL B1 carrier bug
General coverage panoramic intercept receiver
General coverage panoramic intercept receiver (2 GHz)
Dutch intercept receiver for 1st generation car phones
USSR (Russia)
ICOM IC-R9000 communications receiver
 About intercept receivers

TSCM equipment
Wire-line bug detector
Non-linear Junction Detector
Russian countermeasures receiver for the 100 MHz to 12 GHz frequency range
Mason surveillance receivers
Micro-Tel precision surveillance receivers
Scanlock series of TSCM receivers and other Audiotel equipment
Innovative add-on for the Scanlock Mark VB
Various bug detection devices made by Research Electronics International (REI)
Enhanced Omni-Spectral Correlator (bug finder)
Dating Ranger 2 bug tracer
Body worn record detector and bug detector
Portable RF probe monitor (bug finder)
Powerful hand-held bug tracer
Cable checker for mains cables and telephone lines
Sadelco FS-3 field strength meter
NRP field strength indicator with built-in frequency counter
Dare CR-3000/C frequency counter with integrated field-strength indicator
Rohde & Schwarz FSH-3 portable spectrum analyzer
HE-100 directional antennas
ZAP Checker - field strength indicator
Optoelectronics Scout 40 automatic frequency counter 10 MHz - 1.4 GHz
Capri (7042) LW receiver, used by the Stasi for finding carrier frequency bugs
Kopchik aperiodic surveillance detection receiver
PR-100 Portable Digital Receiver
 About Technical Surveillance and Countermeasures

Wired intercept equipment
Lauschempfänger (intercept amplifier) LE-35
Lauschempfänger (intercept amplifier) LE-40
Verstärker 41 (amplifier 41)
Drahtlauschempfänger (klein). Wire tapping device (WWII).
CIA wire tapping device for on-hook telephones (1960)
Lawful analogue telephone intercept system developed by the Dutch PTT
 About wire tapping

Related subjects
Dutch Radio Monitoring Service, Agentschap Telecom (AT), formerly known as: Radio Controle Dienst (RCD)
Covert listening devices (conceled microphones and transmitters)
Surveillance, intercept and measurement antennas
This small receiver was used during WWII to locate clandestine transmitters, mainly operated by German agents in and around London. The unit is housed in a Bakelite enclosure and its lid acts as the frequency range 'plug-in' as well as the direction-sensitive antenna.

The receiver is commonly known as the GPO-receiver, but its official name was Tester WL-53400. It was only built in small quantities.

 More information
GPO Receiver (Tester WL.53400)

BC-792-A   SCR-504-A
BC-792 – also known as SCR-504 – was a portable covert direction finder, developed in 1943 and used by the OSS (the predecessor of the CIA) for finding clandestine transmitters operated by spies during World War II.

The device is concealed as a regular leather travel suitcase, and was also used during the early part of the Cold War in various European countries.

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BC-792-A direction finder inside leather suitcase

Gürtelpeiler   wanted item

The Gürtelpeiler was probably the first body-worn intercept receiver. It was used during WWII by the German secret services to locate clandestine transmitters operating in countries occupied by the Germans.

The valve-based receiver can be concealed under the operator's clothing with a loop antenna around the neck.

 More information

Original Gürtelpeiler

National HRO
The National HRO was a valve-based (tube) shortwave general coverage communications receiver, manufactured by the National Radio Company (National) in Malden (Massachusetts, USA) from 1935 onwards.

The receiver was intended for military and amateur use and became very popular for intercept work during WWII. Different versions of the radio were in production until the 1950s.

 More information

National HRO-5

The AR-88 was a valve-based shortwave general coverage communications receiver, developed and built by the Radio Corporation of America (RCA) in the early 1940s.

Although the receiver was initially intended as the successor to the AR-77 amateur receiver, the outbreak of WWII made it evolve into a professional high-end military-grade intercept receiver for which cost was no object.

 More information

RCA AR-88 receiver

Hallicrafters SX-28
The SX-28 and the later SX-28A were AM/CW communication receivers, developed and built by Hallicrafters Inc. in Chicago (USA) in 1940, a few years before the US got involved in WWII.

It is one of the most popular receivers every built by Hallicrafters, and was used heavily for intercept work during the war. The receiver is also known as Super Skyrider.

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Hallicrafters SX-28A

SSR-201 was an aperiodic or non-selective receiver, developed during WWII for use by the OSS, the forerunner of the CIA. It was used for finding clandestine radio stations, operated by – mainly German – spies in the US and in the UK.

After the war, the device was also used by the Radio Monitoring Services of several European countries.

 More information

SSR-201 aperiodic receiver

USSR (Russia)
During the Cold War, the USSR (Russia) developed a series of highly portable intercept receivers that were deployed in most Warsaw Pact countries. Such receivers where generally carried around the operator's waist, hidden under his clothing.

They also developed stationary and mobile intercept radios and other direction finding equipment.

 More information

Soyka intercept receiver

Wilhelm Quante StSG-52
This German-built portable direction finding receiver was used in the Netherlands in the early 60s to track down clandestine radio stations and foreign secret agents. The receiver is housed in a wooden case, so that the internal window-antenna can be used. It is operated by a trigger-switch hidden under the carrying handle.

 More information
Qante StGS-52 portable radio direction finder

Telefunken PE-484
The PE-484 was a body-wearable miniature direction finder (Kleinstpeilemfänger) introduced around 1958 by Telefunken in Germany. It could be hidden inconspicuously under the operator's clothing and was intended for tracking down clandestine radio stations. In some countries, the PE-484 was used until the early 1980s.

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PE-484/3 receiver

This is a rare short-wave direction finder built in Chechoslowakia around 1948. It comes with four plug-in modules that can be inserted at the bottom of the unit. Each plug-in unit covers a specific frequency range.

It was used by the Czech Secret Police to track down clandestine (spy) radio stations during the Cold War.

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RM-301 with three additional plug-in units

FBA Peiler   Nahfeldausforschungsgerät
This small hand-held direction finder that covers 3 to 145 MHz, was built by the Austrian Radio Monitoring Service of the ÖPT in 1963, especially for unobtrusively searching for clandestine radio stations, such as Cold War spy transmitters.

The receiver is fully transistorized and comes with 15 frequency plug-in units, nicely packed in a sturdy metal carrying case.

 More information
FU-303 ready for use

Mason was a manufacturer of TSCM equipment in the USA. Between 1960 and 1990, Mason developed a wide range of modular portable bug-finding receivers, including the so-called Mini Probe Receivers.

Mason equipment was widely used by government organisations world-wide and the latest models are still in use today.

 More information
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Micro-Tel was an electronics company based in Hunt Valley (Baltimore, US), specialized in developing an building precision surveillance receivers for the US Goverment, the Department of Defense (DoD), and various other agencies.

Starting in the 1960s, the company built a wide range of high-end surveillance receivers and complementary equipment. Today, they are known as Cobham Defense Electronics SIGINT.

 More information
Micro-Tel MSR-901

Scanlock is a series of automatic bug-tracing receivers, developed and marketed by Audiotel in the UK. Audiotel have been developing and manufacturing TSCM equipment since the late 1970s and they are still in business today.

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Scanlock Mark VB in operation

COMPUSCAN was an add-on to the Scanlock Mark VB bug tracer (shown above). It allowed a target area to be compared to a safe zone several miles away. Any differences were then identified as possible suspected signals.

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Research Electronics International (REI) is a US manufacturer of a wide range of TSCM equipment, ranging from simplug bug detectors to fully computer controlled correlation receivers and spectrum analyzers.

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Close-up of the CPM-700 front panel

This valve-based surveillance receiver was developed by the CIA in 1958 and covers 50 - 200 MHz. It was used for monitoring and for the reception of covert listening devices (bugs).

The receiver is based on the military R-744, which as a similar front panel.

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Telescopic antenna mounted on the SRR-4

The SRR-8 was a countermeasures receiver, developed by the CIA between 1961 and 1963. It covers 30-1000 MHz in FM/AM and PM, and was suitable for stationary as well as mobile use.

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XRR-8 (SRR-8) CIA surveillance receiver

The SR-209 (CIA designator: SRR-23) was a high-end surveillance receiver, developed in the mid-1960s by ACL in Gaithersburg (Maryland, USA). It is suitable for frequencies between 2 MHz and 12 GHZ, divided over several bands, each of which required a separate plug-in tuner.

The receiver is suitable for AM, FM, CW and Pulse, and has three IF bandwidths, selectable from a wide range of IF-plug-ins.

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SR-209 surveillance receiver

The American company OAR built a wide range of radio direction finders that were intended as a navigational aid aboard ships. Special versions, the so-called 9xx-range, were made for locating clandestine radio stations (pirates).

The image on the right shows the ADF-940 which has a built-in 40-channel scanner for the 27 MHz citizens band (CB).

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Kolibrie (hummingbird) was a car phone intercept receiver developed by the Police Signals Service in The Netherlands in the early 1990s. It was intended for intercepting criminal conversations on the early analogue car phone networks.

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Front panel of the Kolibrie, with the unique ID plug

Another item that was very popular with the Dutch police was the CR-3000/C frequency counter with built-in optical and acoustical field-strength indicator.

It was used for quickly finding the frequencies that were used by criminals for hand-held communication and for tracking devices.

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Dare CR-3000/C

In the 1980s and 1990s, Schlumberger GmbH developed a series of high performance digital programmable precision receivers, under the name Minilock. The receivers were used by many agencies for intercepting, measuring and fingerprinting radio signals.

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Operating the Minilock 6900 Control Unit

The EB-100 is a small portable surveillance receiver build in the 1980s by Rohde & Schwarz in Munich (Germany). It was intended for a variety of jobs, including frequency monitoring, radio surveillance, radio intercept, EMC measurements and direction finding.

Due to its small size and wide frequency range, it is extremely useful for bug tracing. EB-100 is also known as MINIPORT.

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EB-100 at the desktop

The EB-200 is the successor to the EB-100. It is a portable receiver that covers all frequencies between 10 kHz and 3 GHz, with a wide variety of modulation types: AM, FM, CW, LSB, USB, Pulse and I/Q. It is one of the first receivers that has a fully digital IF-stage with DSP technology.

The radio was intended for monitoring of the frequency spectrum and for locating sources of transmission, including covert listening devices.

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EB-200 receiver in operation

Bodrog was a series of wideband VHF and UHF receivers, developed and built in Czechoslovakia, especially for the reception of FM radio bugs.

The version shown here is the A-variant that was used for the VHF-H band. It was supplied with a mains PSU and a removable battery pack.

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Bodrog bug receiver

The FSH-3 is a portable spectrum analyzer developed by Rohde & Schwarz in Munich (Germany). It covers all frequencies between 100 kHz and 3 GHz and is suitable for HF measurements as well as for bug tracing.

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FSH-3 portable spectrum analyzer

Delta-V is a small hand-held differential RF detector that allows easy bug detection in a room, in a car or on a person, without in-depth knownledge and expertise. The device is powered by an internal 9V battery.

Although the first version of Delta-V dates back to 1989, it has been updated and enhanced several times since, and is still available from the manufacturer today (2013).

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The original Delta-V bug detector

The TCM-03 was a device for detecting bugs on the mains power cables and on the (analogue) telephone lines. It was introduced in 1989 and was succeeded by the TCM-03 Mark II in 1992. The TCM-03 was sold until 2013.

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TCM-03 Cable Checker (initial version)

2170 Stasi Receiver
During the days of the Cold War, the secret service of the former DDR (East Germany), also known as the Stasi, used this receiver to monitor domestic and foreign radio traffic.

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Controls of the 2170 Stasi Receiver

Orchidea-2 was a device that was able to find a covert listening device (bug) that was connected to a wire line, such the power network, remote door openers, telephone lines and TV cabling.

The device is usually carried in an unobtrusive Samonite-style briefcase, together with a set of ancillaries, and has a built-in oscilloscope.

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Orchidea-2 main unit

Osobnjak was a range of high-end counter­measures receivers, developed by the Soviets for protection against resonant cavity microphones, a special kind of passive covert listening devices (bugs) that were activated by a strong RF signal.

As the Soviets were the first to employ resonant cavity microphones, they knew that sooner or later their Western counterparts would use the same technology against them.

 More information
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  1. Wikipedia, Technical surveillance counter-measures
    Retrieved November 2015.
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© Crypto Museum. Created: Monday 03 August 2009. Last changed: Wednesday, 02 March 2022 - 09:16 CET.
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