Disassemble an electromagnetic wave radiation tester

Recently, a friend brought me a broken device and asked me to repair it. It turned out to be an electromagnetic wave radiation tester. The screws on the shell were broken and the protective lens of the LCD panel was gone. However, I was very interested in this instrument. I had always wanted to find an opportunity to compare the instruments produced by regular manufacturers with my own DIY electromagnetic radiation tester. 1: The appearance of the device just after it was disassembled
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Unfortunately, the components were all worn out and I could only guess the model based on the circuit.
The workmanship was OK. I found out that the problem was that the power switch pin was broken and poorly soldered. After fixing it, everything was normal when I turned it on.
Here is a picture: The radiation value during the mobile phone call was measured to be 1321 u W /cm2. The warning light was on and the buzzer sounded.
Let's take a look at the radiation from a computer keyboard. It is 4671 u W / cm2, much higher than a mobile phone.

This is a comparison with the electromagnetic radiation tester I made. The green light on mine indicates radiation.

After one centimeter forward, the radiation increased by more than 300. His device began to issue a warning, and my tester also lit up a red light, indicating that the radiation was very strong. His receiving antenna is at the front end, and the high, medium and low frequencies must be manually selected by pushing the switch. My fully automatic high, medium and low frequencies can all be measured. In comparison, my sensitivity is better than its. It alarms when it is two centimeters away from the keyboard, and mine alarms when it is 5 centimeters away.
This teardown ends here, welcome to watch.

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