This circuit consists of a single Hartley oscillator using a bipolar transistor that can generate signals in the range of 1 MHz to 10 MHz with great stability. The circuit shown in the figure has L1 and CV designed to determine the operating frequency range. For operation between 1 MHz and 3 MHz, L1 can consist of 50 + 15 turns 28 of wire on a 0.8 cm diameter and 12 cm long ferrite rod. For greater stability the source must be stabilized, the ceramic capacitors and the transistor can be replaced with equivalents. In a more critical application, the output coupling capacitor should be silver mica.
