An RF radiation indicator with LED level indication, which simplifies the configuration of transceiver equipment and can also be used to search for covert information retrieval devices (bugs, beacons).
Specifications:
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frequency of detected RF radiation: up to 500MHz
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supply voltage: 7-10V
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current consumption: <40mA
Schematic diagram:
The signal, amplified by the UHF transistor VT1, is fed to a balanced detector, assembled on diodes VD3-VD6, the balance of which is controlled by resistor R4. The detected signal is fed to the differential amplifier DA1.1. Voltage comparators are assembled on the op amp DA1.2-DA2.4, to which LEDs HL1-HL7 are connected. Resistors R10 - R16 set the reference voltages of the comparators.
Application of the device: after switching on, it is necessary to balance the bridge with the resistor R4 and make the HL1 LED glow. As an antenna, use pins 200-300mm long, or a telescopic antenna.
Element layout:
Notes: to reduce the sensitivity of the device to external stray interference, it is recommended to additionally install a 4.7nF capacitor C7. To increase the stability of operation, and eliminate UHF self-excitation, it is necessary to remove the L1 choke, or replace it with a 50...100 Ohm resistor.
The data presented in the product description are for reference only and may differ from those indicated by the manufacturer.
