advance aircraft radio communication receiver

The communications between commercial aircraft and the ground can be interesting, amusing and sometimes even disturbing. However radios that receive the approximately 220MHz to 400MHz band commonly used for aircraft (both military and commercial) are not easily found. And scanners can be complicated, large and expensive. With an easy to build circuit such as this one, everyone can enjoy listening in on these conversations.

Schematic

Parts

Part Total Qty. Description Substitutions R1, R3 2 47K 1/4W Resistor R2 1 10K 1/4W Resistor R4 1 4.7K 1/4W Resistor R5 1 5K Linear Taper Pot R6 1 2.2K 1/4W Resistor C1, C2, C3, C6 4 0.001uF Ceramic Disc Capacitor C4 1 2.2pF Ceramic Disc Capacitor C5 1 1pF Ceramic Disc Capacitor C7 1 15uF 15V Electrolytic Capacitor C8 1 18pF Variable Capacitor D1 1 1N82 Diode Q1 1 2N918 NPN Transistor L1 1 See Notes L2 1 1.8uH Inductor ANT1 1 Approx. 18 Inch Wire Antenna MISC 1 PC Board, Wire, Knob For C8

Notes

1. The circuit originally appeared in the Think Tank column of the Sept. 1995 issue of Popular Electronics.
2. L1 is made by winding 2 turns of 22 AWG magnet wire on a 5/32 drill bit. This inductor can be modified to shift the frequency range of the circuit.
3. The antenna can also be placed at the anode of D1 if overload is a problem with it connected to the emitter of Q1
4. R5 adjusts regen and thus sensitivity.