What is sdr and how to use it?

Exploring the World of SDR: Bringing the Frequency Spectrum to the Screen

Written by: Ayberk Korkmaz – Electrical & Electronics Engineer | Amateur Radio Operator TB7AEK | Broadcast Technologies Specialist

In the past, listening to radio waves required bulky and complex equipment. Today, with a simple USB dongle, a piece of software, and a decent antenna, we can visually explore and analyze the entire RF spectrum on our computers.

This revolution is made possible by Software Defined Radio (SDR).

As both an engineer and an amateur radio enthusiast, I find great joy in diving into the world of SDR, which bridges digital technology and radio communication in fascinating ways.

🔍 What is SDR?

In traditional radios, signal processing (like filtering, demodulating, decoding) is handled by dedicated hardware.
In an SDR setup, these processes are carried out by software, using digital signals from a basic RF front-end.

So it works like this:

🎛️ Analog RF → 🎙️ ADC (Analog-to-Digital Converter) → 💻 Software processing → 🔊 Output

This means with a single device, we can listen to various modulation types (FM, AM, SSB, CW, DMR, even TETRA) and monitor wide frequency ranges with ease.

🛠️ SDR Devices I Use

🔸 RTL-SDR V3

• A very popular and budget-friendly entry-level SDR.

• Covers roughly 500 kHz to 1.7 GHz.

• I use it for FM radio, ADS-B aircraft tracking, NOAA satellite reception, and scanning local public safety bands.

🔸 HackRF One

• A more advanced SDR capable of both receiving and transmitting (under legal limits and restrictions).

• Operates between 1 MHz and 6 GHz.

• Ideal for signal analysis, digital decoding, and experimenting with RF in the lab.

🔸 SDRplay RSP1A

• Offers greater sensitivity and lower noise.

• Equipped with a 14-bit ADC for a wider dynamic range.

• Perfect for HF, VHF, and UHF reception with professional clarity.

💻 Software Makes the Magic

The real power of SDR is unlocked through the software we pair it with.

• SDR# (SDRSharp) – Excellent with RTL-SDR, highly customizable with plugins.

• GNU Radio – Allows block-based signal processing system design.

• CubicSDR, HDSDR, GQRX – Great cross-platform options.

• SigDigger – One of my favorites for spectrum analysis and digital signal inspection.

📡 The Amateur Radio Perspective

For a ham like me, SDR devices are like a laboratory for the airwaves.
They allow me to:

• Track band openings and propagation changes

• Monitor weak signals and distant transmissions

• Decode digital modes like FT8, RTTY, PSK31

• Analyze repeater signals and noise characteristics

It’s an invaluable tool for both everyday listening and deep technical exploration.

🔬 Engineering Insights

From an RF engineering standpoint, SDR is an incredible educational and experimental platform.
It enables:

• Real-time spectrum analysis

• Digital filtering and modulation algorithm testing

• DSP experimentation

• Open-source system customization

I can visualize, measure, and even simulate RF behavior in a controlled and flexible environment.

🎯 Final Thoughts

SDR sits at the intersection of amateur radio and digital innovation.
With affordable hardware and powerful software, we can monitor, decode, and explore vast parts of the radio spectrum—something that was once limited to high-end lab equipment.

For me, SDR is more than just a hobby.
It's a test bench, an RF observatory, and a gateway to continuous learning and experimentation.

📡 Stay tuned, keep exploring the waves!
🎙️ Ayberk Korkmaz – TB7AEK
www.ayberkkorkmaz.com