The circuit presented is quite simple, employing tone modulation of the signal. To receive the signal, a common receiver is used, and the audio signal is applied to PLL filters (NE567, for example) for separation. The circuit provides excellent power thanks to the use of the CR078 transistor (up to 5 W). The operation is in the 27 MHz band, in this case, depending on the crystal used (a 37.12 MHz crystal is used). The antenna must be at least 1 meter long and the power must come from an external source or battery. The L1 coil is formed by 13.5 coils of wire 22 or 20 in the form of 8 mm in diameter with an adjustable core. The taps are made at turn 3,5 and 7. A good heat radiator must be used for the transistor.
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