Various diagram

Often we need to see which is ideal for the placement of an antenna, a transmitter or other device for high frequency where its signal can reach and where it leaves point. For this we can use a detector circuit, also called the sniffer, which is tuned to the operating frequency of the desired system. This detector is described in this article is very simple to operate and do, just uses two diodes and two transistors and a half dozen passive components, their frequency of detection is around 2.2Ghz and its sensitivity is pretty good.

RF detector circuit for High Frequency

Its operation is simple, the transistors Q1 and Q2 are BFS17 are being used with RF amplifiers. LED1 can be replaced by a VU to have greater precision in signal check. The circuit has a very broad frequency tuned, it will capture RF signals from microwaves, cell phones, WIFI, etc.. I believe that the transistor can be replaced by BFS17 BRF92 or BFG591, which are easier to find here.

Detector RF High Frequency

The circuit must be mounted in a metal box to minimize capacitive effects of hand and other external interference, only the antenna must be out of caixa.Para test the detector, as you approach a signal source, the 1 LED gets brighter. The simplicity of the circuit, for sure it will capture unwanted signals, especially harmonics powerful transmitters, but is still reliable equipment.