This article presents an amplifier to the antenna with a bandwidth of 80… 130 MHz. Its design is surprisingly simple, as his work. Especially good amplifier used in car radios.
The amplifier circuit diagram is shown in Figure 1.
rice. 1
The transistor T1 operates in a classic case with an external database, which is polarized by a resistor divider R1, R3. The signal from the antenna is supplied via a capacitor C1 to the emitter of T1, while the output capacitor is also connected to a coil T1. The elements have been chosen in such a way, to the amplifier side corresponded to the standard rod or a telescopic antenna, and output impedance – 75 ohm.
Coils L1 and L2 are such parameters:
- L1 – diameter of approximately 3 mm, 10 turns
- L2 – diameter 5 mm, 13 turns.