The use of analog spy devices becomes outdated, with the development of digital technology, most spy devices are now low power and high frequency.

To scan modern spy devices, we need more sensitive detectors with the ability to detect ultrafast digital pulses from technologies like 4G.

Emissions in the digital mode, are made by pulses and not by continuous carrier modulation as it is in the analog mode, the digital pulses up to a certain speed can be detected with analog technology, but for 3G and more recent technology, the detection with analog detectors is no longer possible.

The 3G technology has been introduced to cell phones about 15 years ago, but many commercially available detectors continue to use analogue technology, so these detectors only detect analog spies and digital ones up to GSM, do not detect 3G, 4G, and faster technology.

It is important to note that many analog detectors have been upgraded and now shows the information on the display, but that does not mean having the ability to detect current digital technologies, it may be just a digital panel, not a digital detector.

SiGe’s active logarithmic detection is the main system currently used for the detection of digital signals, it can detect the ultra-fast 3G and 4G pulses of current systems.

In addition to a fast and sensitive detection system, the device must have an antenna that first receive the signals and then send it to the detector, so that the quality of the antenna is also very important.

An antenna that does not resonate with the signals does not receive it and transmit to the detector properly, there is signal loss before detection and the measurement is incorrect.

The most commonly used telescopic antenna does not operate at high frequencies and is suitable only for low frequency detectors.

Several special antennas have been developed to facilitate the scanning and localization of modern digital spy devices.

Directional antennas indicate the direction of the highest signal level, and also help to verify if the signal comes from the environment being swept or outside.

Antenna with extender facilitate the location of spy devices installed in hard to reach places.

Other antennas may also aid in scanning where interference exists.

If there is external interference from AM and FM radio transmissions, we can use specific high frequency antenna, with built-in filter  blocking these frequencies, eliminating interference, getting better signal from the high frequency spy devices.

On the other hand, in order to locate analog spy devices that transmit on FM and VHF frequencies, we use a low-frequency with built-in filter antenna to block signals from high-frequency digital devices, Wi-Fi networks and cell phones, much more practical, with the possibility of even discover analog spy by audio correlation.