Shortwave SW Transmitter Circuit

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This is an intriguing SW transmitter circuit or shortwave transmitter circuit tutorial, presented here in detail. Basically, the circuit is utilizing 12 MHz crystals to transmit the radio waves. Because of this 12 MHz crystal, the circuit won’t float its frequency. Thus, it broadcast its radio waves at exactly 12MHz.

Furthermore, The short wave or SW transmitter circuit operates in a shortwave HF band. Hence, it ranges from 3 MHz to 30 MHz only. Generally, it is utilized for short-range communication. But, in case you’re searching for the least expensive shortwave transmitter circuit. Thus, this DIY SW transmitter is demonstrated here for you!

Moreover, this SW transmitter is low power and entirely steady in operation. Also, it utilizes a 3 terminal ceramic resonator to set the radio frequency. Additionally, two signal-amplifying transistors 2N2904A and 2N3053 are also added up in the circuit schematic.

Hardware Components

The following components are required to make Shortwave Transmitter Circuit

S.No	Components	Value	Qty
1	NPN Transistor	2N2904A	1
2	NPN Transistor	2N3053	1
3	Ceramic Resonator	12MHz Xtal	1
4	Speaker	4Ω 2W	1
5	Antenna	–	1
6	Resistor	4.7K, 100K, 22, 10K, 47K Ω	1, 1, 1, 1, 1
7	Capacitor	0.01µF, 100µF	1, 1
8	Battery	12V	1

2N3053 Pinout

For a detailed description of pinout, dimension features, and specifications download the datasheet of 2N3053

2N2904 Pinout

For a detailed description of pinout, dimension features, and specifications download the datasheet of 2N2904

Shortwave Transmitter Circuit

Circuit Operation

Accordingly, the circuit is utilizing a 4-Ohms 2-watt speaker as a mouthpiece. This speaker changes the sound signals into electrical signals very effectively. Firstly, these sound signals amplify by a 2N2904A transistor. Therefore, after amplification, the signals regulate the carrier frequency. Which is acquired from the 2N3053 transistor. Additionally, the length of this transmitter is only 25 to 30 meters. Yet it can be additionally stretched out by expanding the radio wire length with appropriate matching.

Although this SW transmitter circuit can reach around 5 meters. However, you can build the range effectively with a basic RF enhancer and a low-pass channel arrangement.

Generally, you can’t simply interface a receiver to the sound input. That’s why this transmitter circuit needs an enhanced signal input. Therefore, it should be enough to modulate the amplitude of the radio waves.

The antenna plays the main role in the scope of this shortwave transmitter. Hence, without antennas, these signals won’t go more than one meter far. Moreover, the frequency can be changed a little (0.1-0.2 MHz). It can be done by including a capacitor in arrangement with the ceramic resonator.