The range of this small FM transmitter can exceed 100 meters. L1 has 4 turns of wire 20 to 22 without a core in the form of 1 cm. The antenna is a rigid wire from 10 cm to 40 cm. Q1 can be a BC548 and Q2 a BF494 or 2N2222. The microphone is an electret. The circuit also works with 6 V. V5 can be any common trimmer of 20 to 50 pF of maximum capacitance.
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