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Intercept Receivers
Technical Surveillance and Counter Measures

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 for a full description of each device. Please note that the list is my no means complete. If you have any further information to offer, or better even: if you have surplus equipment available for the Crypto Museum, please contact us.

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

 Index of intercept receivers
Direction Finders
GPO Receiver (UK) GPO German Gürtelpeiler, used during WWII Gürtel Wilhelm Quante St.Sg.52 (Germany) Quante Telefunken PE-484 Kleinstpeilempfänger PE-484 RZ-301 (CZ) RZ-301 Soyka (USSR) Soyka Filin (USSR) Filin Sinitsa (USSR) Sinitsa

Communications receivers
National HRO receivers HRO RCA AR-88 receiver AR-88 Hallicrafters SX-28 Super Skyrider receiver SX-28 Siemens R-IV (R4) Abwehr receiver R-IV 2170 Intercept Receiver as used by the Stasi in the former DDR 2170 Minilock 6900 Programmable Precision Measurement Receiver 6900 Minilock 6910 Programmable Precision Measurement Receiver 6910 Rohde & Schwarz EB-100 portable surveillance receiver EB-100
General coverage panoramic intercept receiver PAN-1000 Dutch intercept receiver for 1st generation car phones Kolibrie

TSCM Equipment
Mason surveillance receivers Mason Micro-Tel precision surveillance receivers Micro-Tel Scanlock series of TSCM receivers and other Audiotel equipment Scanlock Innovative add-on for the Scanlock Mark VB Compuscan Various bug detection devices made by Research Electronics International (REI) REI Powerful hand-held bug tracer Delta-V Cable checker for mains cables and telephone lines TCM-03 Dare CR-3000/C frequency counter with integrated field-strength indicator CR-3000/C
Rohde & Schwarz FSH-3 portable spectrum analyzer FSH-3 HE-100 directional antennas HE-100

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.

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GPO Receiver (Tester WL.53400)

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.

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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.

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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.

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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

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.

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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.

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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

RZ-301 (CZ)
This is a rare short-wave direction finder built in Chechoslowakia. 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.

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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.

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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.

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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

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 Kolibri

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 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

Further information

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© Copyright 2009-2013, Paul Reuvers & Marc Simons. Last changed: Wednesday, 09 July 2014 - 19:32 CET
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