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Radio Direction Finder
- not in collection
The DAB-3 was a complete Radio Direction Finding System, or
Radio Direction Finder (RDF),
developed in 1942 by the Collins Radio Company
in Cedar Rapids (Iowa, USA), for the US Navy.
The unit is suitable for the 2000 to 18,100 kHz range,
and was used during WWII for locating German U-Boats. After the war
they were used in Europe as a Cold War
radio countermeasure.
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DAB consisted of a double receiver with two long horizontal arms.
At the end of each arm was a cross-connected loop antenna. By measuring
the phase difference between the two antennas and displaying it on an
oscilloscope, it was possible to get an accurate bearing of a radio
signal [B].
The system can be seen as a shore based variant of the spaced loop
direction finding system, that was developed by the Marconi Company
and the UK National Physical Laboratories. In practice, it was the US
variant of the UK's HF/DF (Huf-Duf).
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The DAB system was installed in a two-floor wooden building that also acted as
its concealment. A description of the dimensions and materials
were supplied in the instruction manual [A]. It was
constructed in such a way that the building had minimal effects on the quality
and bearing of the intercepted radio signal. The antenna had to be rotated
manually by an operator standing behind the receiver, in order to obtain
a bearing.
The DAB system was developed by Collins during WWII.
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Four variants were
manufactured, known as DAB, DAB-1, DAB-2 and DAB-3, all of which are
more or less identical. Once the war was over, several DAB stations were
installed along the European North Sea coast, in order to be prepared for
the event of a potential war with the
Soviet Union.
In the Netherlands, 7 DAB stations were
erected. They were used in the early years of the
Cold War for monitoring
East-European radio traffic and following the movements of troops behind
the Iron Curtain. The
Dutch Radio Monitoring Service RCD
was responsible for their operation.
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Over time, the DAB systems were gradually replaced by modern alternatives,
that were installed in the existing DAB houses.
As far as we know, two of the seven DAB locations in the Netherlands
have survived: Post GOLF in Wilhelminadorp (near Goes, Netherlands)
– now the home base of Radio Club De Bevelanden [2] –
and Post HOTEL in Hoogezand, which has recently been restored.
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A complete DAB-3 system consisted of the following major units:
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55A-2 Tuner Unit A 2 55B-2 Tuner Unit B 2 55C-2 Oscillator Unit 2 55D-2 Mixer Unit 2 347A-2 IF Amplifier 2 409R-2 Power Supply 347E-2 1 Commutator 2 26R-2 Audio Amplifier 54G-2 Monitor Unit 2 82S-2 Meter Panel 101T-2 Control Panel - Miscellaneous Equipment 347B-2 Oscilloscope Amp. & Motor Relay 348E-3 Right Loop Assembly 348E-4 Left Loop Assembly
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From serial number 17 onwards, Commutator Unit 347E-3 was used.
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Spares available for sale.
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A number of modules of a DAB-3 system are held in the collection of an
associated museum in the Netherlands. At present it is not possible to
build a complete DAB-3 system from these modules, but they could be of use
to another museum or a private collector when restoring an existing DAB-3
installation or for displaying purposes.
If you are interested, please contact us.
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Spares available for sale
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- 54G-2
- 55A-2
- 55B-2
- 55C-2
- 55D-2
- 347A-2
- 347E-3 (2 pieces)
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© Crypto Museum. Created: Friday 07 April 2017. Last changed: Monday, 09 January 2023 - 13:00 CET.
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![Original DAB-hut, now serving as the amateur radio station of Radio Club De Bevelanden in Goes (Netherlands). Image via Google Maps [2].](img/bevelanden.jpg)
