This is a simple wide band VHF preamplifier that based on PNP transistor. This circuit is inexpensive circuit. The circuit may be used as a signal booster with VHF receivers whose front end suffers from low sensitivity (such as many valve and army surplus types). The frequency range of the preamplifier is roughly from 75MHz to 150MHz. This is the figure of the circuit.
The operation of the circuit is the two inductors in the circuit are home made. L1 consists of 10turns of 24SWG enameled copper wire; the internal diameter is 3mm, no core. Inductor L2 has 13 turns of the same wires, and an internal diameter of 5mm; no core is used either. A construction tip: close-wind the inductors using 3 and 5mm drill bits respectively as temporary formers. The prototype of the preamplifier was successfully used with an 88-108 MHz FM broadcast receiver and a 2-metre VHF ham receiver. The preamplifier draws about 2.5mA from a 5-volt supply.
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