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StSG-52
Portable direction finder

The StSG-52 is a portable radio direction finder built by Wilhelm Quante in Wuppertal (Germany) in 1952. It was used in the 1950s and 1960s for locating clandestine radio stations and foreign secret agents. Officially described as a Störspannungs-Suchgerät 1 (StSG) [1], the receiver was based on the earlier Störsuch- und Meßgerät StG-50, that was developed by Quante in 1950 [B].

StGS 52 is a single conversion super-hetero­dyne receiver with the intermetiate frequency (IF) at 470 kHz. It contains 5 valves (3 x DF91, DK92 and DAF91) and is powered by two battery sets: 1.5V for the heater and 75V anode voltage.

It covers three frequency bands:
  • LW: 150 kHz - 350 kHz
  • MW: 520 kHz - 1.4 MHz
  • GW: 1.02 MHz - 1.4 MHz
  
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The receiver is housed in a wooden case, which allows an internal 'window' coil to be used as the direction-finding antenna. When receiving a radio station, the operator rotates the receiver, in order to determine the direction of maximum (or minimum) field strength, using the S-meter at the bottom left. This procedure was repeated several times from different positions, until the location of the transmitter could be determined. It can also be used with an external antenna.

As the receiver is valve-based, it consumes more power from the batteries than a modern one. For this reason, the StSG-52 is operated by a trigger-switch that is hidden under the carrying grip. This trigger-principle was used before on a wartime direction finder made by Siemens. Due to its rather limited frequency range (150 kHz to 2.7 MHz), the StSG-52 was replaced later in 1952 by its successor the ASRV-52 that was suitable for frequencies up to 11 MHz.

  1. Störspannungs-Suchgerät = Interference Signal Finder.

PLEASE HELP — The above information is all we have at the moment. We have not been able to find circuit diagrams and a suitable user manual for this device. Even the manufacturer, the former Quante, has not been able to help us any further, as details about this device are missing from their records [1]. If you have additional information, or additional accessories, please contact us.
The complete StSG52 unit
The trigger-switch hidden under the handle
The field-strength indicator
The frequency dial (one lane for each band)
PTT RCD internal inventory number
The interior of the StSG52
Close-up of the adjustable parts
Warranty card for the valves
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The complete StSG52 unit
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The trigger-switch hidden under the handle
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The field-strength indicator
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The frequency dial (one lane for each band)
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PTT RCD internal inventory number
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The interior of the StSG52
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Close-up of the adjustable parts
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Warranty card for the valves

Examples of use
RCD   Netherlands
A large number of StSG-52 units was used by the Dutch Radio Monitoring Service (RCD) – at the time headquartered in The Hague – for locating clandestine radio stations, such as radio pirates and foreign intelligence agents. The units were deployed throughout the country and were in use until the mid-1960s. Units that were used by the RCD can be recognised by an extra ID-plate that is fitted on the control panel, just below the leather grip.

 More about the RCD


Bundespost   Germany
In Germany, the Quante StSG 52 was not only used for finding clandestine radio stations, but also for locating TV sets. In the early days of television, customers had to pay a fee for a permit to receive television and radio broadcasts. If you did not pay for a reception permit, you risked a fine or, worse, imprisonment. As the local oscillator (LO) of a TV set emitted a signal that could be picked up with a sensitive receiver outside the house, the Deutsche Bundespost (German Post Office) used Quante direction finders for locating non-registered (and hence illegal) viewers.

Two men with a Quante StSG 52, locating TV receivers, probably in Berling, in 1956.

The image above shows two employees of the German Post Office in front of a Volkswagen van of the Funkmessdienst (Radio Monitoring Service) of the Deutsche Bundespost on a street, probably somewhere in Berlin, in September 1956. The man on the right carries a Quante StSG 52 on his shoulder, whilst holding a directional antenna in his hand. The other man holds a Telefunken Teleport 5 two-way radio in his hands and is probably communicating with another search team.

Two men with a Quante StSG 52, locating TV receivers, probably in Berling, in 1956.
Close-up of the Quante direction finder
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Two men with a Quante StSG 52, locating TV receivers, probably in Berling, in 1956.
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Close-up of the Quante direction finder

Specifications
  • Brand
    Wilhelm Quante
  • Model
    StSG-52
  • Type
    Direction finder
  • Bands
    3 (L, M, G)
  • Frequency
    L: 150-350 kHz
    M: 520 kHz - 1.4 MHz
    G: 1.02 - 1.4 MHz
  • Power
    LT: 1.5V (4 1.5V batteries connected in parallel)
    HT: 75V DC (anode battery)
  • Antenna
    Internal: directional coil
    External (magic wand)
Documentation
  1. Wilhelm Quante, Funkstörspannungs-Messgerät ASRV-52
    User Manual (German). Date unknown, but probably 1952.

  2. Wilhelm Quante, Störsuch- und Meßgerät St G 50
    User Manual and circuit diagram (German). 29 June 1950. 1
     Circuit diagram in high resolution
  1. StG-50 manual kindly supplied by Gabriele Garbuglia from Italy.

References
  1. Personal correspondence between a previous StSG-52 owner and Quante AG
    30 November 1993. Crypto Museum #300719.

  2. Wikipedia, Quante (Unternehmen)
    History of Quante (German). Retrieved 12 October 2011.

  3. 3M, Information der Quante AG Umzug nach Neuss/Lieferabwicklung
    Information about Quante moving to Neuss (German). 12 September 2004.
    Site no longer active in January 2013

  4. QFM - Quante Fernmeldemontagen GmbH, Werdegang
    QFM Website. Retrieved 12 October 2011.
Further information
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Crypto Museum. Created: Monday 03 August 2009. Last changed: Tuesday, 29 March 2022 - 19:20 CET.
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