Click for homepage
Ranger 2
Automatic bug finder - under construction

Ranger 2 was a TSCM receiver, also known as a bug finder, developed and built around 1991 1 by Datong in Leeds (UK). The device is built around a staircase (harmonics) receiver – pioneered by competitor Audiotel – which is basically copied from the Audiotel Scanlock 2000. The digital backend of the device however, shows significant improvements over the Audiotel design [1].

Ranger 2 is housed in a black metal enclosure, similar to the one of its predecessor the Ranger Model 890. All controls and connections are located at the front panel. The device is powered by 6 internal C-size NiCd batteries, that can be recharged with the supplied AC mains adapter.

The device was supplied in an unobtrusive black executive style briefcase, in which the manuals, headset, external speaker, telescopic antenna and battery charger were also stowed. It had to be removed from the case before operation. A leather carrying case was available separately.
  
Datong Ranger 2

Datong Ranger 2 was the successor to the original Ranger Model 890, and has an improved user interface. In many respects, the Ranger is a direct clone of the Audiotel Scanlock 2000, which in turn was a polished-up remake of the Scanlock Mark VB. The RF front-end of the Ranger is a 100% copy of the one used in the Scanlock 2000 [1]. It is based on the harmonics receiver, also known as the staircase receiver, invented in 1962 by Lee Tracey and later marketed by Audiotel. Datong was able to use the design, as competitor Audiotel was unable to prove the ownership. 2

Although the analogue front-end was identical to that of the competition, the back-end was not. The Ranger has a much better post-processing than the Scanlock 2000, which is something that – according to its (then) technical director – Audiotel had failed to do until the Scanlock ECM [1].

  1. Estimation based on the date codes on the components and the date of the manuals.
  2. It is likely that Lee Tracey never patented his invention, as he had a principle aversion against patents [2]. Had he done that in 1962, the patent would have expired by the time of the dispute anyway.

Briefcase with Datung Ranger 2
Datong Ranger 2
Datong Ranger 2
Front panel
Front panel
Speaker for sounding TONE in a room
Accessory socket
Front panel detail
A
×
A
1 / 8
Briefcase with Datung Ranger 2
A
2 / 8
Datong Ranger 2
A
3 / 8
Datong Ranger 2
A
4 / 8
Front panel
A
5 / 8
Front panel
A
6 / 8
Speaker for sounding TONE in a room
A
7 / 8
Accessory socket
A
8 / 8
Front panel detail

Parts
Briefcase
External loudspeaker
Headphones
Telescopic antenna
AC mains adapter
AC
User Guide and Reference Manual
Briefcase
The complete kit is stowed in an unobtrusive black briefcase of the era. It has a foam interior, in which the various items are stowed. At the left is the receiver itself. For operation, it has to be removed from the briefcase.

The manuals are stowed inside the case lid.
  
Datung Ranger 2 stowed in briefcase

Speaker
This external speaker could be connected to the 7-pin DIN socket at the bottom left of the front panel. It is used for generating a sound that can be recognised by the receiver whilst scanning the frequency bands.

Although using this acoustic tone generator is very effective, it gives away the fact that the room is being sweeped for bugs, and may alert the eavesdropping party.
  
Speaker for sounding TONE in a room

Headphones
When operating the Ranger 2, the detected audio is played via the internal speaker of the device. As this may alert the eavesdropping party, it is advised to use a pair of headphones instead.

The image on the right shows the small foldable headphones that came with the device. It was supplied in a plastic storage container.
  
Foldable headphones

Antenna
The receiver was usually operated with the supplied telescopic antenna shown in the image on the right. If the receiver is connected upright, it can be connected to the BNC socket at the top left of the front panel.

When using the receiver in horizontal position, a BNC knee-adapter should be used.
  
Telescopic antenna

Mains adapter
When sweeping a room, the receiver is usually powered by the internal NiCd batteries, that can be recharged by the mains adapter shown in the image on the right. It takes approx. 10 hours to fully charge the batteries.

This adapter can also be used to power the receiver directly from the mains, but this will only work when the batteries are fully charged.
  
Battery charger

Manuals
Each Ranger 2 was supplied with two manuals: (1) a simplified user guide, and (2) a reference manual. The manuals were stowed inside the lid of the briefcase, and can be downloaded below.

 Download simplified user manual
 Download reference manual
  
Manuals

Briefcase with Datung Ranger 2
Datung Ranger 2 stowed in briefcase
Ranger 2 with accessories inside briefcase
Manuals stowed in document compartment of briefcase
Manuals
Telescopic antenna
Foldable headphones in plastic container
Foldable headphones
Speaker for sounding TONE in a room
Battery charger
B
×
B
1 / 10
Briefcase with Datung Ranger 2
B
2 / 10
Datung Ranger 2 stowed in briefcase
B
3 / 10
Ranger 2 with accessories inside briefcase
B
4 / 10
Manuals stowed in document compartment of briefcase
B
5 / 10
Manuals
B
6 / 10
Telescopic antenna
B
7 / 10
Foldable headphones in plastic container
B
8 / 10
Foldable headphones
B
9 / 10
Speaker for sounding TONE in a room
B
10 / 10
Battery charger

Interior
Interior - Case shells removed
Interior - control board (top)
Interior - receiver side (bottom)
Front-end
Receiver
Reference oscillator
Digital PLL
Receiver detail
Control board
Battery compartment
Main processor (CPU)
Front panel interior and wiring
C
×
C
1 / 12
Interior - Case shells removed
C
2 / 12
Interior - control board (top)
C
3 / 12
Interior - receiver side (bottom)
C
4 / 12
Front-end
C
5 / 12
Receiver
C
6 / 12
Reference oscillator
C
7 / 12
Digital PLL
C
8 / 12
Receiver detail
C
9 / 12
Control board
C
10 / 12
Battery compartment
C
11 / 12
Main processor (CPU)
C
12 / 12
Front panel interior and wiring

Restoration
  • Exterior cleaned (stains from decomposed foam removed)
  • Leaking NiCd batteries removed
  • Battery compartment cleaned thoroughly
  • Internal PSU problem partially resolved
  • Briefcase exterior cleaned
  • Briefcase interior (foam) replaced
Leaking NiCd batteries
Leaking NiCd batteries
Cleaned battery compartment
D
×
D
1 / 3
Leaking NiCd batteries
D
2 / 3
Leaking NiCd batteries
D
3 / 3
Cleaned battery compartment

Documentation
  1. Ranger 2: Simplified User Guide
    Datong Electronics Ltd., 20 August 1991.

  2. Ranger 2: Reference Manual
    Datong Electronics Ltd., 2 May 1991.
References
  1. Ian Melling, Former technical director at Audiotel
    Personal correspondence, 26 April 2018.

  2. Lee Tracey, Inventor of the harmonics receiver
    Interview and personal correspondence, 23 May 2013.
Further information
Any links shown in red are currently unavailable. If you like the information on this website, why not make a donation?
Crypto Museum. Created: Thursday 08 October 2020. Last changed: Tuesday, 08 December 2020 - 10:19 CET.
Click for homepage