This is a very cheap and simple bug detector that is supposed to make sound when it detect RF signals between 100Mhz-2600Mhz. I found out that it doesn't do what it supposed to do,since its sensitivity is very poor.It detects signals of some mobile phones(while some mobile phones it doesn't detect),wi-fi transmitters,garage doors remote control signals etc.at a distance of maximum 5 cm in the best case.Thats all. Regard to my description,What may be the method of that cheap bug detector:detection of magnetic fields,electric fields or maybe both?
I meant,if you compare it to a standard EMF meter which has 3 measurment functions:
1)function of detecting only electric field strength.(v/m)
2)function of detecting only magnetic field strength(gauss/tesla)
3)function of detecting RF/microwave strength in w/m2.
What function is similar to the method of the bug detector detections?
It seems like the third one(RF strength)is the most similar,but the problem is,as i mentioned,the bug detector response only close to the transmitter,while RF strength may measured at the far field.
So,it makes me difficult to understand.
Here is the PCB circuit of the bug detector:
Thanks in advance.