Vector Signal Analyzers.
Seller Granit Island Group
James M. Atkinson, Granite Island Group
Vector Signal Analyzers
Digital eavesdropping and audio monitoring devices are commonly available for just a few hundred dollars , and can be easily hidden in the spread spectrum of wireless phone signals .
The governments of the United States, China, and France have been using these devices for many years. Many of these digital devices have been found in offices, cars, and homes of employees. These devices are usually hidden inside other electronic devices such as computers, televisions, and copy machines.
Detecting a digital device becomes a very difficult task unless the equipment is subjected to tampering and physical search. These devices often operate at very low (sub-milliwatt) power levels and signal bandwidths often exceeding 8 MHz.
A vector signal analyzer (VSA) is an instrument that provides modulation analysis of modern digital signals. The instrument is similar to an oscilloscope, however, a VSA provides additional analysis of the phase (I) and quadrature-phase (Q) components of the signal. Modern surveillance devices that use vector modulation technology can often be identified by examining the I Q components of an electromagnetic anomaly.
Components emitted by AM, FM, BPQSK, QSK, QAM, pulse and other types of modulation are easily recognized and evaluated in a bandwidth of up to 20 MHz. This makes it possible to identify the most exotic digital surveillance devices. Higher bandwidth eavesdropping devices can be detected using compression or Bragg cell receivers.
A vector signal analyzer requires a dual I Q signal input, which is generally only available on dedicated radios (Rockwell or Watkins-Johnson), or modern spectrum analyzers (such as the HP-71910AP). The signal is then passed to a spectrum analyzer which combines the signals into a single complex signal that is contained only in the digital domain.
Complex signal analysis algorithms are then applied to the input signal to extract the modulation parameters. This will then allow the ability to demodulate most suspect signals.
The HP-89410A vector signal analyzer has quickly become a favorite of the TSCM industry, and will likely be a staple tool for the next few years.
The HP-8981B is also an excellent vector modulation analyzer, but has a very limited bandwidth. The instrument is also analog, as opposed to the HP-89410A which is a digital instrument.