Single tube TV antenna amplifier

The single-tube TV antenna amplifier shown in the figure below uses few components, has low cost, is simple to make, requires no adjustment, and has high performance indicators. It is especially suitable for amateur production by radio enthusiasts.

Principle and production:

The TV signal received by the antenna is coupled to the base of the transistor BG through the capacitor C1, and then output through the collector resonant circuit. The bandwidth of the amplifier is 46-240MHz, the power gain scale Kp>16dB, the noise of the amplifier is small, and it has a strong suppression ability for 10-38MHz. The working voltage of the amplifier is 3V +-0.5V, and the power consumption current is only about 3mA, so it can be powered by two No. 5 batteries. Transistor BG can choose to use ultra-high frequency tubes such as 9018, 3DG80B, and 3DG84B. Capacitors C1-C3 use ceramic capacitors. C4 uses an electrolytic capacitor with low leakage. Coils L1 and L2 use enameled wire with a wire diameter of 0.35mm, which is wound on a round rod with a diameter of 3.5mm. L1 is wound flatly for 9 turns, and L2 is wound flatly for 11 turns. The entire circuit is installed in a shielding box. The input and output lines are all 75Ω cables.