Two+transistor+superheterodyne+shortwave+receiver

This is two transistor and two IF transformer based superheterodyne receiver which is designed to receive 13m to 41m bands. With quiet good external antenna this receiver performs similar to commercially available shortwave receiver and its audio quality is in very satisfactory level.



During our prototyping we test this receiver with several oscillators and rod coils. The best configuration which we found for 13m - 41m bands are described in below illustrations. Standard shortwave oscillator coil (Green) and rod coil are also working with this receiver but it will narrow the bandwidth of the receiver. For rod coil use 100mm to 160mm ferrite rod. The antenna which we use with this receiver is 2 × 12 feet T antenna.





This receiver can be constructing on PCB, breadboard or commonly available //veroboard// or stripboard. For tuning use Polyvaricon or air variable capacitor. For precision tuning, connect small trimmer capacitor with parallel to variable capacitor’s gangs or use mechanical wheel assembly with the variable capacitor.





This receiver is design to work with 9V regulated power supply and it requires external AF amplifier to drive the headphone or speaker. In our testing we use TDA2050 audio power amplifier with this receiver.

With small wire antenna this receiver is capable to receive most of the stations which including //CRI//, //BBC World service//, //All India Radio//, etc. in Sri Lanka. To receive other stations which including //VoA//, //Radio France//, //Deutsche Welle//, //ABC// we use our 2 × 12 feet T antenna.

For initial IF transformer tuning we recommended to use quiet large antenna and some powerful station. For example in Sri Lanka, CRI (17855.00kHz, 17730.00kHz, etc.) or AIR (11710.00kHz, 13710.00kHz, 9690.00kHz, 11620.00kHz, etc.) are quiet easy to locate and tune.

Project Related Downloads
[|Schematic and inductor details of superheterodyne shortwave receiver project.]