Understanding the SST5462 and Its Role
At the heart of this project is the SST5462, a high-input impedance, low-noise JFET transistor. This component is widely used in amplification stages of sensitive circuits such as audio preamps and RF front-ends. In the context of our radio, it will serve as the key amplification element to help extract weak AM signals from the air and make them strong enough for audio detection.The SST5462's attributes make it especially suitable for building a simple regenerative or tuned radio frequency (TRF) receiver. Its low gate leakage and high transconductance mean better signal clarity and less unwanted interference—exactly what we need for capturing clear audio from AM stations.
Conceptual Overview of the Project
Our project centers around a minimalist AM receiver circuit that uses just a few key components beyond the SST5462. The receiver will:● Pick up AM signals from the air using a tuned antenna circuit
● Use the SST5462 to amplify the signal
● Detect and extract the audio from the carrier wave
● Deliver the audio to an earpiece or small speaker
This approach not only creates a functional device but also provides a clear, intuitive view into how traditional radios work without overwhelming you with digital complexities or software layers.
Gathering the Components
While the SST5462 is the primary active component, a few passive elements will also be essential. Here’s a general idea of what you’ll need:● One SST5462 JFET transistor
● An AM antenna (a long piece of wire or a loop antenna works)
● A tuning coil (hand-wound on a ferrite rod or pre-purchased)
● A variable capacitor (for tuning the AM band)
● A germanium diode or a small signal diode for demodulation
● A coupling capacitor
● A high-impedance earphone or small audio amplifier and speaker
● A small battery (like a 9V) and holder
● Resistors for biasing the JFET
● A simple PCB or breadboard for assembly
● Wires and a soldering kit
This small collection of components is more than enough to create a working prototype of an AM radio receiver using analog electronics only.
Step-by-Step Construction
1. Setting Up the Tuning Circuit
Start with the heart of any radio—the tuning circuit. This section filters out everything except the frequency of the AM station you want to hear. Using a coil and a variable capacitor connected in parallel, this "tank circuit" resonates at a particular frequency.If you're winding your own coil, use enamel-coated copper wire and a ferrite rod. Wind about 60 to 100 turns, depending on the band range you want to cover. Then connect this coil to a variable capacitor—typically in the 100 to 365 pF range.
This combination will allow you to manually tune the radio across the AM broadcast band. The antenna wire should connect to one end of the coil or be loosely coupled via an extra winding.
2. Connecting the SST5462 for Signal Amplification
This is where the SST5462 shines. Mount the transistor onto your breadboard or PCB. Configure it in a common-source configuration, which provides good voltage gain and is ideal for RF amplification.To bias the SST5462 properly, use a resistor between the source and ground to develop the source voltage, and connect the gate to ground through a high-value resistor (in the megaohm range). This sets up the JFET to amplify small signals from the tuned circuit.
Connect the drain of the JFET through a resistor to the positive terminal of the battery. The amplified signal at the drain will now be strong enough to process further.
3. Adding the Detector Circuit
Once the signal has been amplified, it needs to be demodulated. This means stripping the audio information from the AM carrier wave. This is done using a diode detector circuit.Connect a small signal diode (a germanium diode like the 1N34A works very well) to the drain of the JFET. Follow this with a coupling capacitor to block DC and pass only the audio signal.
This simple detector circuit will extract the audio from the modulated carrier, converting it into a waveform that you can hear.
4. Driving the Audio Output
The audio output is usually quite weak at this stage, so you’ll need a sensitive high-impedance earphone to hear it clearly. If you prefer, you can use a small audio amplifier module (like a battery-powered LM386-based board) to drive a small speaker.Connect the output of the detector circuit to the input of your earphone or amplifier. The sounds of your selected AM station should now be audible, provided you’re within range of a strong broadcast signal and have tuned the circuit correctly.
Tuning and Troubleshooting
Getting the best reception requires some fine-tuning:● Adjust the variable capacitor slowly until you hear a clear station.
● Position the antenna wire for optimal reception—near a window or stretched along a wall helps.
● Check power connections if the circuit is silent.
● Use shielded wires if interference becomes a problem.
Don’t worry if you don’t get perfect results right away. Analog circuits like this are quite sensitive to layout, component tolerances, and environmental factors. Part of the fun is tweaking and improving performance through experimentation.
Enclosure and Finishing Touches
Once you’ve confirmed the radio works as expected, consider housing it in a small enclosure. A wooden box or repurposed electronics case gives it a retro feel. Drill holes for the tuning knob (attached to the variable capacitor), the antenna jack, and the earphone output.Label the front panel with basic tuning marks or frequencies if desired. You could also add a small LED power indicator, powered through a resistor from the battery, to show when the device is on.
If you enjoy design work, the aesthetic of a homemade radio can be quite beautiful. You can use brass fittings, vintage dials, or even reclaimed materials to give it a truly unique look.
What You Learn from This Project
This DIY radio receiver project using the SST5462 is more than just a cool build—it’s a deep learning experience in analog electronics. You will:● Understand the basics of tuning circuits and resonance
● Explore transistor biasing and amplification using a JFET
● See real-world signal detection and demodulation
● Experience the satisfaction of hearing a live radio signal through a handmade device
Unlike projects based on digital components or microcontrollers, this radio is purely analog. It works entirely through natural physical principles like resonance, semiconductor junction behavior, and electromagnetic wave propagation. There's something deeply rewarding about that.
Expanding the Project
Once you’ve successfully built the basic radio, you might want to enhance it further. Here are a few ideas:● Add a regenerative feedback loop for improved sensitivity and selectivity
● Replace the earphone with a full amplifier and speaker system
● Add a tuning scale with printed frequency markers
● Use a larger, directional antenna for long-distance reception
● Combine with a solar cell to make a self-powered radio
Every addition helps refine your understanding and opens doors to new areas of learning.
Final Thoughts
Building an AM radio receiver using the SST5462 is a deeply fulfilling project. It takes you out of the world of digital screens and into the realm of invisible signals, analog electronics, and the kind of hands-on creativity that powered early 20th-century technology.There’s something magical about tuning a homemade circuit and hearing a real voice or piece of music broadcast from miles away. With a handful of components, a JFET transistor, and a little patience, you bring the airwaves to life with your own hands.
US 14164 
GB 12001 
AU 9868 
CA 9792 
IE 5390 
BR 2504 
NZ 2272 
SG 1155 
