Economical and practical transmission power test pen

I have been engaged in radio communication maintenance since 1981. Based on more than 20 years of work practice, I have made some testing tools, among which there is an effective handheld walkie-talkie transmission power test pen circuit as shown in Figure 1.



If it is installed in the test pen holder of a multimeter, as long as the pen needle is close to the top of the handheld walkie-talkie transmitting antenna, you can accurately judge whether the walkie-talkie has power transmission from the light of the light-emitting diode D2, and you can roughly judge the size of the transmission power according to the brightness of the light-emitting diode. The production cost does not exceed one yuan.

In addition, based on the circuit diagram 1, it is changed to Figure 2; that is, the light-emitting diode is removed, and the DC2.5-1OV block of the digital multimeter is connected to the vacant A and B ends to measure the test points of the car radio or handheld walkie-talkie power amplifier stage and each drive stage to determine which stage is faulty. This is something that a power meter cannot do.

After long-term work practice verification, I think this is a good tool for repairing walkie-talkies