ZC300

The ZC 300 is a radio frequency field strength tester with the ability to detect very weak signals (down to ambient levels of radiation that exist around us. The ambient radiation level is usually due to local FM and TV broadcasts.) The ZC 300 detects signals spanning the microwave, UHF, VHF and high frequency spectrum, covering a 1 MHz to 8+ GHz bandwidth. This includes 5.8, 5.2, 4.5, 3.5, 2.4 and 1.2 GHz covert cameras and bugs, 2.4, 1.8, and 0.9 GHz cell phones and wireless phones; 300-400 MHz walkie-talkies, car keys and garage door openers; 70-150 MHz FM transmission; 49 MHz bugs and even 27 MHz citizen-band transmissions. Detection at 2.4 GHz is so sensitive, it will detect an operating “sealed” microwave oven at 12 meters away and pick-up 2.4 GHz transmitting bugs at 8 meters distance.

The unique feature of the Zap Checker 300 is the ability to use special antennas and band pass filters through a SMA coaxial input connector. Depending upon the frequency and directionality of the externally connected antenna, the ZC 300 becomes a highly directional frequency-specific instrument which is ideal for counter-surveillance detection and for aligning transmitter/receiver antennas over far distances.

The 1.8 – 6.4 GHz Log-Periodic Antenna available with the ZC 300 boosts the sensitivity by 3 times. It also narrows the directional detection characteristics of the ZC 300 to a longer, thinner scan pattern directed along the long axis of the antenna. With prior instrumentation it was necessary to “sweep” a room by moving the detection device from 30 to 70 cm away from the walls, ceiling and floor in a raster scanning mode, similar to the travel of an electron-beam in a television CRT. That is time consuming and back-straining work! Using the Zap Checker 300 with antenna, the covert device can be initially detected from 8+ meters away. That is outside the room or at the door. Then, from the door itself, the walls, ceiling and floor can be scanned by pointing the directional antenna and hand-sweeping the room. Now we can “SWEEP THE ROOM FROM THE DOOR”, detecting the direction of the covert transmitter from a distance.

Once the direction of the covert device is detected, we move closer to it while decreasing the gain using the sensitivity controller, keeping the signal measurement within the limits of the meter scale. When we are so close that the meter reading is constantly at the highest level, we reset the ZC 300 to a wider-dynamic-range by switching to the MID or LOG detection mode. In the LOG mode it is possible to pinpoint the bug up to a few cm away without overwhelming the instrument by the high signal level at such close proximity. If the signal is too strong, use the SMA connector to screw on an external attenuator in series between the antenna and the ZC 300. Use as many attenuators as necessary to control the signal level for accurate detection. Now we can identify that tiny hole in the wall as the pinpoint opening to a covert camera or microphone!

The frequency specificity and directionality of the ZC 300 is controlled by the external antenna connected to its SMA input. The 1.8-6.4 GHz LOG Periodic Antenna works well in this manner. Using a 50 cm long 2.4 GHz Yagi antenna improves the sensitivity about 7-8 fold at 2.4 GHz and narrows the detection width to about 5 degrees. The ZC 300 can be directly connected to such antennas or connected using a flexible cable.

Avoid measuring transmitted signals which are directly connected to the SMA input. The signal levels of such devices can be large enough to damage the sensitive receiver input of the ZC 300.

Directional antennas usually have increased sensitivity along their longer axis. Pointing the front of the antenna towards the transmitting device gives the strongest pickup – but there is also an enhanced pickup 180 degrees away from that direction to the rear of the antenna. The differences between the front and rear sensitivities are usually specified by the front to back ratio in dB. More directional antennas, (usually longer in length), tend to have higher front to back ratios. When specifying the direction of the signal source, be aware of the diminished signal enhancement directed from the rear of the antenna.

The Zap Checker 300 is an extremely sensitive instrument which detects signals that are coupled to it in any manner. In this way the ZC 300 is more like a wideband receiver with an antenna input. The proximity to a metal cabinet, desk, or automobile can affect the reading. Also, the proximity of your hand or body may increase the reading, acting as the antenna and coupling a stronger signal to the input. It is even possible to reflect signals directed toward your body and redirect them to the ZC 300. Be aware that although an external antenna is optimized to enhance reception within a particular band of frequencies, it is also capable of detecting stronger signals from out-of-band frequencies.

When initially using the ZC 300, it is often perplexing why detected signals appear so fickle. By moving closer to the window, the signal strength increases (the walls of the room tend to shield the outside signals). The walls of the room define a resonant cavity – the room itself. Radio waves bounce off the walls, ceiling and floor to give enhanced “hot” spots (where the signals converge) or “cold” spots which are devoid of signals. Different frequencies have their own hot and cold spots. When moving the ZC 300 just a few cm the detected signals may change dramatically due to these intensified and rarefied signal regions.

Polarization effects may also be apparent with the ZC 300, especially when an external antenna is used. Polarization effects are noted when rotating the antenna from a horizontal to a vertical plane. The change in signal strength gives an indication of the polarization of the transmitting source. It is even possible to note changes in signal intensity in outdoor wide-open spaces. Buildings, trees, people, mountains, etc. all reflect signals that produce variations in signal strength. It is important to consider these other factors when detecting and locating weak covert signals. Experience with use will overcome many of the hurdles.

The Zap Checker 300 speeds up and simplifies the installation of wireless devices – from security cameras to wireless computer networks. With wireless installations the ZC 300 verifies the signal strength of the transmitting device. It identifies the hot and cold spots in the region. Hot and cold spots are usually undesirable as transmitters or receiver sites. It measures the baseline level of RF at these sites and detects any interfering signals (RFI) that may occur. Besides detecting the RFI, the ZC 300 also can identify its source.

The ZC 300 with directional antenna optimizes the radio link between a wireless transmitter and receiver. It is also helpful in selecting a hub site for solid communication with its multiple secondary WLAN sites. Corporate security officers use the Zap Checker to identify potential hacker-sites outside their facilities and to help shield and position wireless transmitters to eliminate those hacker-sites.

The Zap Checker 300 is instrumental in identifying radio frequency interference sources from coronas and arcing insulators on utility poles. By using a directional antenna on the ZC 300 an offending insulator can be located from the ground. This enables utility personnel to quickly and easily identify the problem from a safe distance (Even bolts of lightning are detected by this instrument).

SPECIFICATIONS OF THE ZC 300

Very High sensitivity – with a maximum sensitivity of 45 uV (~-75 dBm) at 2.4 GHz

1 MHz to 8 GHz usable frequency spectrum.

Manual/electronic switching between antenna inputs.

2 internal, fixed antennas that do not require any adjustments.

A switch-selected SMA coaxial connector for external antenna inputs - 50 ohm impedance, DC isolated.

An adjustable sensitivity control – ( 20 dB variable attenuator.)

3 detection modes:

a. Linear – displaying 12 dB of the weakest signals.- For detecting weak signals.
b. LOG – displaying 60 dB of signal strengths.- For pinpointing signal sources.
c. MID – intermediate sensitivity and dynamic range.- For moderate signal readings.

2 Display Modes – An Analog meter and colored LED’s (which are readable from a distance and at nighttime).

A switch-enabled silent vibrator - with vibrations modulated by the signal strength.

A 1.8 – 6.4 GHz Log Periodic Antenna