Radio 144 MHz
Radio 144 MHz is used for operation in the Amateur radio band 144 MHz. This radio is narrowband frequency nodularia. The frequency of the transmitter near 144 MHz depends on quartz and inductor L2, figure 1. Output power of 100 mW.Figure 1
The transmitter used a condenser microphone M1. Microphone sensitivity is adjustable by the variable resistor R1. The microphone amplifier is assembled on the transistor VT1. Trimmer capacitor C3 allows you to slightly adjust the frequency of the carrier. The master oscillator of the radio station is made on the VT2 transistor and operates at the third harmonic quartz. Resonant circuit L3, C5 tuned to the third harmonic of 144 MHz quartz. Next, since the oscillating circuit signal is supplied to the output stage of the radio station which is made on the VT3 transistor. Resonant circuit L5, C10 is also tuned to the third harmonic quartz. Then the carrier frequency of the transmitter through the P-loop is fed to the antenna.