Скачать или смотреть How to make a direct conversion receiver

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This is a direct conversion receiver. It works on the beat of two signals. If the frequency of the two signals is the same, there will be no sound at the output of the mixer. If there is a difference of 100 Hertz, you will hear these 100 Hz.
-why is the frequency of the generator two times lower than the frequency of the receiving signal? The fact is that a mixer with two diodes will switch at each half-wave of the sine wave and therefore the output of the mixer will have double the frequency
--What is the length of the antenna? I used a wire approximately 40 meters long
-What signals can it receive? It receives SSB/CW signals well, AM receives worse