This commercial receiver from the year 1958 uses two AA cells as Power supply. The circuit is intend to receive MW station and the transistors are germanium types not easy to find today.
Figure bellow shows another circuit that allows adjustments in the duty cycle of the output...
May 2017 - The new HMC8500, Analog Devices RF amplifiers with a frequency range of 0.01 GHz to 2.8 GHz...
September 2016 - It can be obtained from Mouser Electronics the new isolated flyback controller...