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RCD Essa CR-3000/C →
Frequency detector
- under construction
BMR-1000 is a mobile frequency counter with built-in field-strength
indicator and acoustic feedback, jointly developed in 1995
by the Dutch Radio Monitoring Service (RCD) 2 and
external contractor Essa Electronics in
IJmuiden (Netherlands). Manufactured by Essa 1
the device was used to determine the frequency of a mobile
radio system in close proximity, in order to be able to intercept it.
The RCD
mainly used it to find clandestine users of the frequency spectrum.
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The device has the form factor of a regular car stereo, allowing it to be
installed unobtrusively in any existing mobile intercept station.
It is powered by the 12V battery of the vehicle.
All connections are located at the rear panel, whilst the controls and readout
are at the front panel.
The BMR-1000 has a frequency range from 30 MHz to 1 GHz and will automatically
lock onto the strongest signal in its vicinity, which is usually the clandestine
station under investigation.
When locked, the 6-digit display will instantly show the
frequency of the intercepted signal.
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The name of the device (BMR-1000) is derived from the initials of three people: Ben and Mart – both working at the RCD
– and Rob - the developer at Essa (SPI) [3][4].
1000 stands for the maximum frequency of 1 GHz.
The BMR-1000 was first manufactured in 1995. The design was improved in 1997.
It has an f/100 output that can be
connected to the PAN-2000 intercept receiver for instant synchronisation. The BMR-1000 was succeeded in 1999 by the Dare CR-3000/C.
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The image below shows the front panel of the BMR-1000. At the centre
is a 6-digit frequency readout, built with red LED 7-segment displays.
To its right are three push buttons for TIME (gate timing), DIM
(reduced light) and LATCH (hold current frequency). To the left of the
display are three potentiometers: GAIN (input sensitivity), THRESHOLD
and VOLUME. The latter controls the volume of the rattle — a rattling sound
that increases with the strength of the intercepted signal.
The device is powered by a DC source between 10 and 15V — typically
the battery of a vehicle — that should be connected to the fixed red/black
wiring at the rear.
A stabilized 12V DC output for a peripheral device is available on
a 3 mm jack at the bottom left of the front panel.
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When our BMR-1000 was added to the collection [1], it was first tested.
We noticed that it did not always read the correct frequency, especially when
the BNC input plug was moved. This appeared to be caused by the silver-plated
contacts of the BNC socket. After cleaning these contacts and bending them
inwards somewhat, it always showed the correct frequency.
It should be noted that the last digits of the display may be a bit 'nervous'.
For example, when feeding it a frequency of 145.200 MHz, the display constantly
toggles between 145.199 and 145.200 MHz. As a result, it may be difficult to
read the correct value. This is inherent to the design. In such cases it is
recommended to press and hold the LATCH button (bottom right).
The device is our collection does not produce any signal on its audio output.
Checking the output with an oscilloscope, reveals that there is no signal
whatsoever. It is likely that the amplifier is broken. It will be difficult
to repair this without the original circuit diagram.
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Device Frequency counter and field strength indicator Purpose Finding clandestine transmissions Model BMR-1000 Manufacturer ESSA, SPI Years 1995-1997 [3] Successor CR-3000/C Frequency 30 MHz - 1 GHz Display 6-digit (red LED 7-segment) Power 10-15V DC Current 360 mA Dimensions ? Weight ? Quantity 50-100 (est.)
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- Anonymous donor, BMR-1000 - THANKS!
April 2009.
- SPI website, List of products ... since 1983
Retrieved April 2019 (via WayBack machine).
- Rob Keij, Essa/SPI director
Personal correspondence, April 2019.
- Anonymous former user, personal correspondence
October 2024.
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© Crypto Museum. Created: Thursday 18 April 2019. Last changed: Wednesday, 11 December 2024 - 20:29 CET.
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