A simple receiver without its own source

It's about construction, which was described years ago by Ing. William Petrík, OK3WAO (OM3WAO). I have modified the available material and I am presenting it to you today. This is not a revolutionary invention or perpetuum mobile – it is a crystal with a single-transistor amplifier. The method of obtaining energy for the amplifier is interesting: from the air. Yes, from the air. The captured electromagnetic energy of a strong station in the medium wave band is used.

Signal from the transmitter, which we want to receive gets from antenna A1 to circuit C2L1, which we tune to the frequency of the transmitter. Upon detection, the signal is applied to the base of the transistor. Its working point should be found using trimmers (R2 a R3) so, to make the income strongest – the gain of the transistor at a given supply voltage is greatest. High-resistance headphones are connected in the collector circuit.

The signal induced on antenna A2 is used to power the receiver. We determine this signal by selecting it from the SV band using the C7C8L2 circuit. The voltage is rectified by diode D2 and filtered by capacitor C6. If we want to avoid the second antenna, or the station is not strong enough at the point of reception, we can power the receiver from the so-called. ground battery. A battery of these dimensions will give us approximately 0.7V and 1mA, that is, we use two to three batteries connected in series to power the receiver. Both the copper and the iron rod must have a diameter of at least 7 mm.

This article is an inspiration rather than another source of electricity. Is interesting, that it does not use natural (water, vietor, sunlight) nor electrochemical sources (batteries, batteries). Who knows how electricity will be distributed in the future?

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