SW Receiver Using MK414

A Short Wave Receiver based on the MK484 (formerly ZN414) that includes the tropical bands and 49 metre bands.

SW Receiver Using MK414 Circuit Diagram

Notes:
The original data sheet for the MK414 states a maximum working frequency is around 4 MHz. SW transmissions are so powerful that this receiver will work well with signals up to about 6 or 7 MHz. The 10k resistor controls the operating voltage for the IC which is critical for good performance.

Coil Details:
The tuned circuit consists of a variable capacitor and fixed air spaced coil. For the coil, I wound between 10 and 20 turns of wire on an empty tube of around 1.5 inches diameter. The turns were spaced so that the overall length was around 3 inches. The variable capacitor tuned 0 - 300 pF but there is plenty of scope for experiment here. One final point, you will need an external antenna to receive broadcasts. I have an outside wire that is about 7 meters long and this was quite effective. The antenna can be connected at either end of the coil or via a series capacitor value between 10pF and 100pF.

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Transmitter and Receiver Infra Red Headphone

Transmitter and receiver circuit using infra red audio signal is applied to emit an audio signal and will received on a headphones. Making his series is not too difficult, the transmitter and receiver circuit scheme can be seen below.

Transmiter schematics

Receiver schematics

After the series finished, you can try to give the audio inputs on the transmitter and point the LED transmitter to the receiver. Maximum distance is a few meters may not be more than 10 meters, but you can listen to music without wires while using infra red.

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