This is a small transmitter is a good stable QRP transmitter, which has many uses, from the HF bands AM transmitter, radio control models, or AM / CW ham-band transmitter. Circuit is almost ridiculously simple, and construction is even simpler. It is basically a single transistor oscillator with very low output impedance, suitable for driving the base of another transitory stage amplifier. Oscillator uses a single coil and crystal. The coil is tuned to a frequency output, which may correspond to the crystal frequency, or harmonics.
Read Source: http://w1.859.telia.com/~u85920178/tx/cw-am_00.htm