The output stage USC
In recent times, as the output stages of the radio apparatuses are widely used integrated amps series C, the Most suitable for these purposes, I believe the use of chips K174UN 14 and K174UN 19 (the analogs - 2003 and 2030, respectively).
Usually chips are used in the model inclusion, although you can use them to better advantage.
The proposed amplifier on the chip CAN was manufactured and tested in transceiver tract RA3PEM "Rosa", instead of the rare nowadays KUN, which is a powerful operational amplifier. In the amplifier entered OOS (chain R4, R6, C2, C5), resulting in the frequency response of the amplifier has a blockage 12 dB/octave at frequencies above 2.7 kHz.
Similarly, the OS can be injected into the ULF on K174UN 14.
S. ZAPOTECO (EW2AH), Molodechno