For testing radio assemblies, I purchased this frequency counter - kit.
According to the manufacturer's description, it can be used both to check quartz as well as to check or measure frequencies in some radio installations.
After making the kit, I noticed that it measures with good accuracy only certain quartzes. Also, I tried to measure the working frequency of some radio installations and I did not succeed.
Later, I noticed that the radio signal to be measured must have a large amplitude.
In this sense, we made a small radio frequency amplifier, composed of two amplification stages, as can be seen in the electrical diagram, presented in the video.
Then I connected this RF amplifier to the corresponding input of the frequency counter, as shown in the images.
To check the functionality of this amplifier, respectively of the meter, I used a simple radio with direct amplification.
As can be seen in the images, I received several radio stations, then I checked the frequencies displayed by the meter, by comparing them with the broadcasting frequencies of the received stations, public frequencies, existing on various internet pages.
I also noticed that this kit works better at voltages between 3.5 and 4 V.