The analog meter gives a reading of radio frequency signal strength. It provides a clearer visual display of rapid signal changes than other types of displays.
Two Light Emitting Diodes (LEDs) are used to give a signal strength indication for viewing at a distance or in low light conditions. The LED display directly correlates with the analog meter readings. The green LED illuminates brightly with little or no meter reading and progressively dims as the meter reading becomes stronger. The red LED begins to illuminate at moderate meter readings and progressively gets brighter at stronger signal levels.
3. SILENT VIBRATOR SWITCH
The silent-vibrator switch turns the silent vibrator mode ON or OFF.
In the LOG (logarithmic) mode the detector senses a large dynamic range of signal strengths. It excels at pinpointing the location of signal sources without overloading the ZC 185 measurements. In the LINEAR mode the detector is at its most sensitive operating mode, allowing it to detect weak signals at a far distance.
The MID (middle) mode is a combination of LOG and LINEAR modes allowing the instrument to detect moderate RF signals with an expanded dynamic range of signal strengths.
The ON-OFF switch for the instrument is coupled with the SENSITIVITY control. The sensitivity control adjusts the amplification of the ZC 185 over a 10 to 1 signal range (20dB).
6. ANALOG – DIGITAL SWITCH
Continuous Radio Frequency signals are detected in the Analog mode. The Digital mode is used when the transmitting device is broadcasting digital or rapidly pulsed analog signals. Digital signals are distinguished from analog signals when measurements in the digital mode are noted to be stronger than in the analog mode.
7. BATTERY COMPARTMENT
The rear battery door allows access to the battery compartment that holds two (2) AA batteries. Alkaline batteries are recommended. (Rechargeable batteries do not work).
The flattened bottom enables the instrument to be placed upright on its end allowing the meter display and LED displays to be visible from a distance.
1. INITIAL SETTINGS
Initial conditions of the ZC 185 should be with the LOG-LINEAR switch in the LINEAR mode, the Vibrator switch turned OFF, and the Analog-Digital switch in the Digital position.
Turn on the ZC 185 by rotating the OFF-SENSITIVITY control to the right.
2. SETTING THE BASELINE, AMBIENT SIGNAL LEVEL
Initially switch to the LINEAR mode for long distance detection of weak RF signals.
Rotate the OFF-SENSITIVITY control from low to high to adjust the sensitivity of the instrument so that the ambient, baseline RF Signal level reads between 10 to 40 on the meter scale. This is a measure of the baseline signal level at that particular location.
3. USING THE DIFFERENT AMPLIFICATION MODES
A detected weak signals will present as an increase above the ambient signal level reading in the LINEAR mode. The far-away weakest signals are detected here.
The MID mode is used for detection and measurement of moderate signal levels.
Switch to LOG mode for localizing and pinpointing the signal source when the transmitted signal reading is too high on the meter scale in the LINEAR and MID modes. The signal source is localized exactly in the LOG mode without overwhelming the meter capabilities.
4. LOCALIZATION
Generally, to determine the location of a transmitting device, move in the direction which increases the signal strength on the ZC 185. As the signal strength increases and the meter reading becomes maximized, switch from LINEAR to MID mode and finally to LOG mode to get to a readable part of the meter scale. The highest reading in the LOG mode is just adjacent to the signal source.
5. SILENT VIBRATOR MODE
The silent vibrator is used when it is difficult to view the displays or when it is desirable not to be noticed when monitoring the RF signal strength. Once a threshold level is exceeded the vibrator turns on and operates in a pulsating manner. The strength of the vibrations increases with an increase in RF field strength, making it easier to locate the signal source without viewing the display.
6. ANALOG – DIGITAL MODES
A continuously broadcasting signal can be measured in either the Analog or Digital modes. When the signal is digital (i.e., it is pulsed on and off at a rapid rate), it gives a relatively low reading in the Analog mode, but measures accurately higher in the Digital mode. This is due to the pulsing of the RF signal. If the signal is rapidly pulsed on and off, the meter display will register an average signal reading of the on and off pulse times in the Analog mode. In Digital mode the pulses are detected as peak-signals which register a higher reading than the average of on and off pulses measured in the Analog mode.