Versión en español
The most simple radio receiver is a Crystal Radio, with some few parts you can make a radio receiver. In this case is for the Shortwave band.
The circuit are inspire from QrpisGud4you but i separate the two coils, one is the filter and the other one as a second filter an detector.
Make a Crystal Radio with audio amplifier with battery is some kind cheat, but in the shortwave we hav no other option, because the transmitters are a thounsands of kilometers far away from receiver, so the signal is very small.
With A.M. Local broadcast station that does not happen and you can hear the audio from local station without any extra battery, only with the same energy from the radio station.
My audio amplifier are a PC speaker with the circuit LM386 as pre amplifier
My antenna are 10 meters long wire in horizontal position t a height of 6 meters from the ground. And the ground connections is a rod buried in the ground.
With this receiver i can tuning from 2.5 to 7 mhz aprox. and i can hear:
I hope to share soon others more simplest crystal radios, with parts you can easily get.
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