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Telefunken PE-484
Miniature direction finder - under construction

PE-484 was a miniature body-wearable radio direction finder (RDF) — in German: Kleinstpeil­empfänger — introduced in 1958 by Telefunken in Ulm (Germany). The device was intended for locating clandestine transmissions and spy radio stations, during the early part of the Cold War.

The set consists of a body wearable miniature receiver that is housed in an ergonomic bakelite enclosure, a loop antenna that can be carried at the back under the clothing, and a field strength indicator disguised as a regular wristwatch. It was designed for unobtrusive – undercover – use.

The receiver cover the frequencies between 57 kHz and 20.6 MHz – with a small gap between 443 and 498 kHz – divided over 10 frequency bands. Each band required a specific cylindrical plug-in coil pack, that also acted as the tuning scale. Audio is delivered to a small earpiece.
  
PE-484/3 receiver

The PE-484 was first introduced in 1958, as a successor to the WWII Gürtelpeiler. It was initially built with miniature valves (tubes), but over time the design was improved several times, and the valves were gradually replaced by modern transistors. The final version – PE-484/5 – was a fully transistorised device. The device was succeeded in 1989 by the completely redesigned PE-484/9.

The closed leather briefcase The open leather briefcase, revealing its contents PE-484/3 receiver Inserting a tuning coil Wrist watch field-strength meter The meter on the wrist
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The closed leather briefcase
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The open leather briefcase, revealing its contents
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PE-484/3 receiver
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Inserting a tuning coil
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Wrist watch field-strength meter
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The meter on the wrist
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Features
All controls and connections are located at the front panel, as shown in the diagram below. At the centre are four small 2-pin sockets — typical for electronic hearing aids of the era — to which the antenna(s), the headphones and the field-strength indicator (i.e. the watch meter) are connected.

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The small tear-shaped knob at the centre is used to switch the device ON and select the desired modulation type (A1 or A3). The frequency is adjusted with the tuning knob at the left. The large numbered dial at the right is for setting the volume level. The small circular knob at the centre is for switching ON the vertical reference antenna and adjusting its phase. The two metal rods at the left and right sides accomodate a canvas belt, by which the receiver can be carried on the body.

Models
The PE-484 was in production for many years, during which time the exterior was never changed. Internally however, the designers gradually made the transition from valves (tubes) to transistors, indicated by the suffixes to the serial number. The first variant did not have a suffix. In 1989, the line was replaced by the short-lived PE-484/9, which had a completely redesigned enclosure.

  • PE-484
    Initial valve-based version
  • PE-484/2
    Hybrid version with valves and transistors
  • PE-484/3
    Improved hybrid version with valves and transistors
  • PE-484/4
    ?
  • PE-484/5
    Fully transistorised version

  • PE-484/9
    Modern version with different layout
Plug-in coils
In the table below, all avilable plug-in coils are listed. In practice, only a selection of these coils would be ordered with the receiver. Especially the lower four ranges I to IV (0.057 to 1.08 MHz) were rearely used and were often omitted. They may therefore be missing from a surviving unit.

Coil From To From To
I 0.057 MHz 0.114 MHz 2630 m 5250 m
II 0.112 MHz 0.224 MHz 1338 m 2680 m
III 0.220 MHz 0.443 MHz 676 m 1363 m
- 0.443 MHz 0.498 MHz 602 m 676 m
IV 0.498 MHz 1.08 MHz 278 m 602 m
V 1.06 MHz 2.225 MHz 135 m 283 m
VI 2.18 MHz 4.51 MHz 66.5 m 137.5 m
VII 4.45 MHz 8.8 MHz 34.1 m 67.3 m
VIII 8.6 MHz 12.9 MHz 23.25 m 34.8 m
IX 12.7 MHz 17.0 MHz 17.65 m 23.62 m
X 16.8 MHz 20.6 MHz 14.55 m 17.85 m



Parts
Basic set
Brow leather briefcase with receiver and accessories Body wearable receiver in bakelite enclosure Body wearable loop antenna Plug-in coil packs Field-strength meter in the shape of a wrist watch Battery charger Stethoscope-style earphones Miniature loudspeaker
Canvas carrying strap Operating instructions
Tripod extension
Large suitcase for storing all items and accessories Tripod Tripod head with compass and fittings Window antenna Telescopic antenna Linear and circular rulers for (map) measurements Accessories and tools Plastic raincoat
Service manual
Leather briefcase
The PE-484 came in the unobtrusive leather briefcase shown in the image on the right. It looks like a regular briefcase, but was in fact purpose-made, and offers space for the receiver and its accessories.

After opening the case, the upper half of the front side can be folded as shown, giving access to two leather bags and four coil pack positions.
  
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Receiver
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PE-484/3 receiver

Loop antenna
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Cloth directional antenna

Frequency plug-ins
The frequency range of the receiver (57 kHz to 20.6 MHz, with a gap from 443 to 498 kHz) is divided over 10 bands, each of which requires a special cylindrical coil pack, that can be inserted into the receiver and acts as a frequency scale.

One coil pack was usually installed in the PR-484 receiver. The four most frequently used coils could be stowed in the hinged flap of the leather briefcase (for quick access) whilst the remaining ones were kept in a leather container.

 Overview of plug-ins

  
Typical plug-in tuning coil

Field strength indicator
One of the most striking features of the PE-484 — copied from the WWII Gürtelpeiler — is the field-strength meter that is disguised as an un­obtrusive wristwatch. It allows the user to check the field-strength of the clandestine (spy) radio signal, whilst pretending to be checking the time.

The wristwatch meter is also a rare item, which is commonly missing from a surviving PE-484, as it was often taken as a souvenir by former users.

  
Field strength indicator disguised as wristwatch. Note the two-pin socket at the left side

Battery charger
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Batteries placed in charger

Earphones
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Headphones

Miniature speaker
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Funnel

Carrying strap
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Operating instructions
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Handbook part 2 (German)

Storage suitcase
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Tripod
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Tripod head
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Window antenna
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Map rulers
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Accessories and tools
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Leather box containing 5 tuning coils The tuning coils inside the leather box 5 spare tuning coils in a leather box Typical plug-in tuning coil Rear of a plug-in coil, showing the contacts. Inserting a tuning coil Field strength indicator disguised as wristwatch
Field strength indicator disguised as wristwatch. Note the two-pin socket at the left side 2-pin socket at the left side of the wristwatch meter The meter on the wrist Mains transformer of battery charger Mains transformer for battery charger Battery charger (closed) Battery charger (open) Batteries placed in charger
Headphones Miniature speaker Funnel Funnel Handbook part 2 (German) With real photographs
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Leather box containing 5 tuning coils
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The tuning coils inside the leather box
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5 spare tuning coils in a leather box
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Typical plug-in tuning coil
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Rear of a plug-in coil, showing the contacts.
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Inserting a tuning coil
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Field strength indicator disguised as wristwatch
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Field strength indicator disguised as wristwatch. Note the two-pin socket at the left side
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2-pin socket at the left side of the wristwatch meter
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The meter on the wrist
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Mains transformer of battery charger
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Mains transformer for battery charger
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Battery charger (closed)
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Battery charger (open)
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Batteries placed in charger
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Headphones
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Miniature speaker
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Funnel
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Funnel
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Handbook part 2 (German)
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With real photographs


Antennas
The PE-484 can use several antennas. First of all, it can use the internal ferrite antenna. For good direction finding however, it needs a (directional) loop antenna and a vertical (omni-directional) help-antenna.

For the latter, two variants are available: an antenna pair made of cloth-encapsulated wires, and a set of fixed antennas. The fixed antennas are intended for field use in combination with the tripod and antenna head. The image on the right shows the body-wearable loop antenna.
  
Cloth directional antenna

Cloth directional antenna Cloth antenna wire entry point Cloth help-antenna Cloth help-antenna Unfolded window antenna Window antenna hinge Telescopic rod antenna The tip of the telescopic rod antenna
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Cloth directional antenna
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Cloth antenna wire entry point
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Cloth help-antenna
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Cloth help-antenna
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Unfolded window antenna
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Window antenna hinge
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Telescopic rod antenna
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The tip of the telescopic rod antenna

Leather briefcase
A standard inconspicuous brown leather briefcase was used for storing the receiver and the basic accessories, such as the additional tuning coils, the user manual, the antennas and the wrist-watch field strength indicator.

In most cases, this is how the PE-484 set was delivered. In the extended version, the briefcase was packed inside a larger leather case, together with a tripod and some other accessories. It made the PE-484 suitable for open field use and static measurements.
  
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The open leather briefcase, revealing its contents Leather box containing 5 tuning coils
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The open leather briefcase, revealing its contents
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Leather box containing 5 tuning coils

Storage case
The PE-484 receiver and all of its accessories can be stored inside a rather large black leather suitcase. This includes the standard brown leather briefcase that is intended for daily use, and a tripod for the fixed directional antennas.

The images below show how the various parts are stored inside the high quality suitcase. The rightmost image shows the antenna head that can be mounted on the tripod for outside field use.
  
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Contents of the suitcase The briefcase inside the suitcase Taking the briefcase out of the suitcase Control sticks and sound funnel Antenna head
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Contents of the suitcase
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The briefcase inside the suitcase
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Taking the briefcase out of the suitcase
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Control sticks and sound funnel
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Antenna head

Tripod
The PE-484 can also be used for static field measurements when mounted on the supplied tripod. A special antenna head with two fixed antennas is then connected to the receiver.   
Tripod

Tripod Antenna head Plastic ruler Angle meter Unfolded window antenna
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Tripod
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Antenna head
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Plastic ruler
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Angle meter
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Unfolded window antenna
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Other accessories
A complete PE-484 set comes with many other accessories, including a screwdriver, rain coat, waist belt, battery charger, etc. Some of these accessories are listed below. Others may be described elsewhere on this page.

For connectivity between the various components of the set, some thin short cables are supplied. These cables all have a rather rare 2-pin plug at the end. Be very careful with these cables and plugs are they are extremely difficult to replace.
  
Headphones

User Manual Headphones Raincoat Screwdriver Canvas waist belt Voltage meter Battery charger Inter-connection cables
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User Manual
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Headphones
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Raincoat
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Screwdriver
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Canvas waist belt
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Voltage meter
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Battery charger
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Inter-connection cables

Interior
The PE484 receiver is easily opened by loosening two screws at one end of the back panel. The other side of the back panel has a hinge, so that you can swing it open like a door. Opening the back door, reveals the electronics inside the receiver. It consists of two miniature Telefunken valves and 5 first-generation transistors.

To the right of the electronic circuit are two mechanical filters. The batteries are in the front compartment. They are mounted in three battery holders that surround a 5-pin 270° DIN socket.
  
Interior of the receiver

Opening the receiver Interior of the receiver Interior of the receiver Interior of the receiver Interior of the receiver Interior of the receiver
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Opening the receiver
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Interior of the receiver
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Interior of the receiver
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Interior of the receiver
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Interior of the receiver
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Interior of the receiver

PE-484 in block buster movie
The PE-484 direction finder can be spotted in the 1977 Dutch block buster movie Soldaat van Oranje (Soldier of Orange). In the scene in which the German Sicherheidsdienst (SD) tries to locate the Robbie's clandestine transmitter, an SD employee wears the PE-484 on her body and uses the wrist-watch meter to establish the location of the transmitter by measuring the field strength.

The female SD employee — who is actually a Dutch collaborator — is played by actress Bruni Heinke. In the previous scene she is helped by her male colleague – played by actor Rijk de Gooijer – to install the PE-484 under her clothes.

The first part of the search is carried out with a receiver that is installed in the back of a small laundry truck. it is used to roughly establish the area in which the transmitter is located. Once the region is narrowed down to just a few houses or blocks, the PE-484 is used for the final part, by finding the position with the highest signal level.
  
Click to see more

It should be noted that the PE-484 is strickly speaking out of place here. It was used to replace the original wartime Gürtelpeiler (waist belt direction finder) which the production team was unable to obtain. Original Gürtelpeilers are extremely rare, and the PE-484 is similar enough – both in appearance and in functionality – to act as a convincing alternative. It should also be noted that in the movie it is the German Sicherheidsdienst (SD) who locates the clandestine transmitter, whereas in most cases this was the law enforcement work of the German Ordnungpolizei (Orpo).

The actual PE-484/2 that was used in the movie Soldier of Orange, came from the collection of Dutch collector Cor Moerman. It later became part of the collection of Museum Jan Corver in Budel (Netherlands) – the Dutch Ham Radio Museum – and is now part of the Crypto Museum collection [4]. Movie screenshots courtesy and copyright 1977, Rob Houwer Film Company (Netherlands) [3].

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Specifications
Known serial numbers
  • PE-484/3
    289 092
    Crypto Museum
  • PE-484/3
    289 078
    Museum Jan Corver Crypto Museum
Documentation
  1. Telefunken, Kleinstpeilgerät PE-484/2 Teil 1
    Vorläufige Kurzbeschreibung und Bedienungsanweisung (German).
    User Manual for the portable direction finder PE-484/2. Germany, April 1959.

  2. Telefunken, Kleinstpeilgerät PE-484/2 Teil 2
    Vorläufige Beschreibung Wirkweise mit Schaltbildern (German).
    Service Manual for the portable direction finder PE-484/2. Germany, April 1959.
References
  1. Telefunken, Radiogoniomètre miniature PE-484/9
    Brochure for the Telefunken PE-484/9 (French).

  2. Louis Meulstee, RDF Receiver PE 484/2
    Wireless for the Warrier. Volume 4. September 2004. ISBN 0952063-36-0.

  3. Rob Houwer Film Company, Soldaat van Oranje
    Movie (Eng.: Soldier of Orange), 1977.

  4. Cor Moerman, Telefunken PE-484/2, S/N 289078 – THANKS !
    Received March 2020.
Further information
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© Crypto Museum. Created: Tuesday 20 April 2010. Last changed: Monday, 18 May 2020 - 10:12 CET.
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