This circuit is designed to make a short pull-up antenna perform like a long wire antenna, while offering no voltage gain.
The circuit boosts the receiver"s performance only if the signal at the antenna is of sufficient level to begin with. This circuit takes a short pull-up antenna that has a high output impedance and couples it to the receiver"s low input impedance through a two-transistor impedance-matching network. Transistor Ql"s high input impedance and high-frequency characteristics make it a good match for the short antenna, and Q2"s low output impedance is a close match for the receiver"s input. This circuit is usable over the range from 100 kHz to 30 MHz.