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Surveillance and measurement antenna
SAS-2 1 is an extremely broadband active
receiving antenna system,
developed around 1994 by Antenna Research Associates, Inc. in Beltsville
(Maryland, USA), for use by the United States
Central Intelligence Agency (CIA)
and national and international law-enforcement agencies.
The antenna is suitable for electric fields only and covers a frequency
range from 100 Hz to 2 GHz.
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The omnidirectional antenna system consists of a combination of a
vertical monopole antenna and a
discone antenna, covering two overlapping frequency bands, known as the
low-band and high-band. The monopole antenna (low-band) covers 100 Hz to 200
MHz, whilst the discone (high-band) covers 30 MHz to 2 GHz (VHF/UHF).
The antenna system is known as active, which means that it contains
two built-in RF amplifiers — one for each band — the output of which is
available from BNC sockets on the enclosure of the pre-amplifier,
at the bottom of the antenna.
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The antenna is extremely useful for surveillance and monitoring purposes,
but also when carrying out measurements, for example as part of a path-loss
survey system, or for EMC compliance and test applications.
For this reason, each SAS-2 antenna system came with an
individual calibration chart. The SAS-2/A and SAS-2/B are still available
from the manufacturer today (2022) [1].
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SAS = Surveillance Antenna System.
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SAS-2/A 100 Hz - 1 GHz (single BNC output) SAS-2/B 100 Hz - 2 GHz (two N outputs) SAS-2/E 100 Hz - 2 GHz (with two outputs and rechargable batteries)
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The diagram below shows the layout of the SAS-2 antenna. At the bottom is
the amplifier with built-in mains power supply unit (PSU). At the top of
the amplifier is a rather thick black mast that ends in a discone antenna,
which consists of a horizontally placed disc and a set of radials
that form the approximation of a cone. This antenna covers
30 MHz to 1 GHz (or 2 GHz).
On top of the discone antenna is another mount in which a vertical
rod can be placed. The vertical rod acts as a monopole antenna that is part
of a non-resonant active antenna system. At the upper end of the monopole
antenna is a horizontal disc which acts as a top capacity. It
extends the band coverage of the antenna. The monopole antenna covers
100 Hz to 200 MHz.
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Device Active monopole/discone antenna Frequency 100 Hz - 2 GHz Low band 100 Hz - 200 MHz High band 30 MHz - 2 GHz Polarization Vertical Directivity Omnidirectional Impedance 50Ω Connector BNC/F Overload 0.5 V/m Mains 110-120V AC, or 220-240V AC (switchable) Batteries Two rechargable cells (internal) Current ~ 50 mA Power 5 Watts Size height: 34.5", diameter: 14" Weight 9 lbs, 12 ounces Temperature 20°F - 130°F Storage -55°F - 100°F
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- SAS-2B sales leaflet
Antenna Research Associates, Inc., August 2013.
- SAS-2/B, Technical Manual
Antenna Research Associates, Inc., July 1994. Issue I.
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© Crypto Museum. Created: Thursday 16 November 2017. Last changed: Sunday, 16 October 2022 - 09:27 CET.
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