long range fm transmitter circuit

  
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The transmitter ambit declared actuality has an added RF ability amplifier stage, afterwards the oscillator stage, to accession the ability achievement to 200-250 milliwatts. With a acceptable analogous 50-ohm arena even antenna or multi-element Yagi antenna, this transmitter can accommodate analytic acceptable arresting backbone up to a ambit of
long range fm transmitter circuit - schematic

about 2 kilometres. The ambit congenital about transistor T1 (BF494) is a basal low-power variable-frequency VHF oscillator. A varicap diode ambit is included to change the abundance of the transmitter and to accommodate abundance accentuation by audio signals. The achievement of the oscillator is about 50 milliwatts. Transistor T2 (2N3866) forms a VHF-class A ability amplifier. It boosts the oscillator signals ½ ability four to bristles times. Thus, 200-250 milliwatts of ability is generated at the beneficiary of transistor T2. For bigger results, accumulate the ambit on a good-quality bottle adhesive lath and abode the transmitter central an aluminium case. Shield the oscillator date application an aluminium sheet. Potentiometer VR1 is acclimated to alter the axiological abundance admitting potentiometer VR2 is acclimated as ability control. For hum-free operation, accomplish the transmitter on a 12V rechargeable array backpack of 10 x 1. 2-volt Ni-Cd cells. Transistor T2 charge be army on a calefaction sink. Do not about-face on the transmitter after a analogous antenna. Adjust both trimmers (VC1 and VC2) for best manual power. Adjust potentiometer VR1 to set the axiological abundance abreast 100 MHz.



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