Integrated Spectrum Analyzers like OSCOR combine capabilities from multiple types of analyzers to locate signals, not just detect them.
In the last few decades, the volume of RF spectrum activity has exploded and shows no indication of slowing as the demand for wireless information transmission grows insatiably. The opportunity to use free airspace for good is equal to the ability for it to be used nefariously. RF safety and security efforts will face significant challenges in coming years to keep pace with increased opportunity for abuse.
One particular area of RF exploitation that is demonstrating significant expansion is illicit surveillance. Availability of cheaper and highly advanced surveillance products at the consumer level has taken technology that was once reserved for an elite field of intelligence specialists, and made it accessible to the average individual. Easy to use video and audio recording transmitters can be disguised and hidden in the most common, ordinary off the shelf products. These malicious devices are being produced in volume and marketed commercially with little restriction. A quick search for “hidden camera” on your favorite online retailer site may yield surprising results.
There are many different types of spectrum analyzers including benchtop models, portable models, handheld units, and Software Defined Radio (SDR) units. While there are many different ways of comparing these products, most choose to focus primarily on the traditional spectrum analyzer specifications such as:
SFDR – Spurious Free Dynamic Range
DANL – Displayed Average Noise Level
However, when using a spectrum analyzer to search for unknown signals which may pose a threat, mobility is another very important factor to consider. When doing a security survey, it is vital to be able to quickly pick up the spectrum analyzer and walk around an environment to compare RF signal strength in different locations.
One of the most common specifications for comparing spectrum analyzers is sweep speed. It is important to understand exactly what resolution is being considered when specifying sweep speed. To start the discussion, let’s look at the OSCOR Spectrum Analyzers which sweep from 10 kHz to 24 GHz in 1 second. Therefore, the sweep speed is 24 GHz/sec with a frequency resolution of 12.2 KHz. This means that every second, it produces a trace of 24 GHz span with 2,000,000 data points. Consequently, if you are using an OSCOR and only sweeping 8 GHz, then the sweep speed is 24 GHz/sec, but now the unit covers the 8 GHz span 3 times in one second.
REI announces that, following a commodity jurisdiction determination issued by the U.S. Department of State – Directorate of Defense Trade Controls (“DDTC”), the REI OSCOR Blue spectrum analyzer (8 GHz and 24 GHz models) is no longer subject to International Traffic in Arms Regulation (“ITAR”) jurisdiction. Effective immediately, the OSCOR Blue is subject to the Export Administration Regulations (“EAR”) administered by the Department of Commerce – Bureau of Industry and Security (“BIS”) and has been assigned to Export Control Classification Number (“ECCN”) 3A992.A. The OSCOR Blue now has the same export control status as the OSCOR Green spectrum analyzer.
When comparing spectrum analyzers, it has become common to reference a 100% Probability of Intercept (POI) specification. POI refers to the minimum transmitter pulse duration that can be detected with a 100% Probability of Intercept. When looking at these types of specifications, it is very important to understand the assumptions behind the claims and how they are calculated; with POI, it is essential to understand the span at which the POI spec is calculated.
To assist with report writing and analysis after a sweep is complete, the OSCOR provides the ability to capture various types of information from the display, demodulated video, and audio signals. All information captured is stored to either a compact flash card or a USB storage device, not the OSCOR itself. In order to recognize an external USB hard drive, the device must be formatted with a FAT file system such as FAT32. If needed, the OSCOR can format the hard drive using the Storage Manager feature (see page 22 of the OSCOR Green manual).
When extended capture and analysis of RF traffic is required, it can be tedious to analyze large volumes of resulting data. The Spectrogram Waterfall function on the OSCOR is an effective tool for visually inspecting RF energy over time. However, the Masking function may be an alternative starting point to help perform signal data analysis more efficiently.
Software Defined Radios (SDR) are becoming more common to use when looking for rogue RF transmissions in certain environments. They may appear to be less expensive simply because there are many tuner modules on the market that provide Spectrum Analyzer capability for very low cost, and there are various suppliers of software and hardware to mix and match all sorts of system combinations. However, total cost of software, antennas probes, cables, software defined receivers, a laptop, etc., can get expensive.