Small Broadcast-Band AM Transmitter

This AM radio circuit is a low power transmitter working on broadcast band. The simplicity is implemented using a single-transistor amplifier stage, and for the stability a crystal is used to excite the 670Hz oscillation. The output power of this AM transmitter circuit is 400 micro watts for antenna. L1 and L3 is 40-300 uH ferrite core antenna. Here is the schematic diagram of the circuit:

[Circuit’s schematic diagram source: Transistor Manual, G.E.]