i agree with Qiaozhi, he is absolutely right when shortcut battery it produce electomagnetic waves with wery large freqency spectrum - from khz to mhz
you can recieve with any radio reciever.
about black box it is for low freqency becose of ferit transformer (may be coil) for me it is generator for 5-10 khz
about board there is antena printed on board very similar to car alarm remote unit working around 422 mhz
there is very strange parts not logical to be together
there is any opamp for taking small signals and to put them in PIC
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