Tagged: rtl2832u

October 5, 2026

sdrtop: A Terminal-Based SDR Bench Tool

Thank you to Viktor László (MusiThang on GitHub), for writing in and sharing with us his new project called sdrtop. sdrtop is a terminal-based SDR tool that is compatible with the HackRF and RTL-SDR. Viktor writes:

I bought a HackRF because I was curious how SDR works and found the whole topic interesting.

Later I wanted to understand what was actually in the radio signals, and I ended up writing a terminal tool for that. Along the way it grew RTL-SDR support too.

sdrtop is a bench instrument in a terminal: spectrum, waterfall, gain and clipping, lab-style readouts, and digital demodulation for measurement, not for listening.

I started it to learn the signal path. What it turned into is a gap I kept hitting: cheap SDRs used for real measurements over SSH, in tmux, or on a cyberdeck, where a heavy GUI just slows you down.

No audio on purpose. If RX stops, the numbers go stale instead of looking fine forever.

I care about being able to trust the numbers, so the signal path is written in Rust from scratch rather than sitting on a DSP library. The only external piece in that chain is the FFT crate. (rustfft).

On RTL-SDR it has native full support (R820T, E4000, R828D): single tuner gain + AGC, spectrum, waterfall, and the measurement panels the dongle can actually back.
HackRF and tinySA are supported as well; Soapy is available in beta for other devices.

Written in Rust, open source, one-person hobby project, and still very much in active development. Classic Bluetooth is in progress; spectrum and lab are what I use every day.

sdrtop reminds us of a few previous terminal-based SDR programs such as sdrrat, as well as terminal-based ADS-B radar displays such as radar-tui and coole-radar.

SDRtop Terminal Based SDR Tool Screenshots

October 1, 2026

Using an Affordable Optical Encoder as an SDR Tuning Wheel

Thank you to Gerrit (PA3BYA) for writing in and sharing a hardware project he completed that combines an affordable optical encoder and a microcontroller with custom firmware to create a high-resolution USB mouse wheel for SDR tuning. Many people prefer using a knob to tune through the bands rather than a keyboard and mouse. Gerrit writes:

Although I initially developed it for use with the RTL-SDR, it is actually a general-purpose tuning solution that can be used with virtually any SDR software. Many SDR projects use a cheap mechanical rotary encoder with, for example, 24 pulses per revolution.

But why settle for a 24-pulse mechanical encoder when an affordable optical encoder can provide 600 pulses per revolution? For this quick SDR experiment, I combined a high-resolution optical encoder with a tiny Digispark ATtiny85 and turned it into a standard USB mouse wheel for tuning.

The result is a surprisingly simple and platform-independent tuning control that works with SDR software on macOS, Windows, Linux, and even a Raspberry Pi.

The encoder he used is a cheap Chinese part, costing around 17 Euros. However, one interesting issue that Gerrit encountered was that the cheap encoder would not reliably operate when powered from 5V, even though the operating voltage was specified as 5V to 24V. To fix this, he suspected that the input LDO was dropping too much voltage at the low 5V end, so he modified the encoder by shorting the input and output of the 78M05 regulator, to allow direct 5V power without any dropout.

His firmware for the ATtiny85 is open source and can be found on GitHub.

The Optical Encoder and ATTiny85 Microcontroller

October 1, 2026

FoxSDR Updates: Node Canvas, Single Map Display, Linux+Android Builds, Locating Air Traffic Radar Positions

Thank you to wonderingStars for writing in and sharing updates to his FoxSDR software program. FoxSDR is a new AI-coded software that supports all common protocols and SDRs.

The first update that wonderingStars notes is the addition of a node canvas where you can wire radios, decoders, speakers, and displays together. It can run up to five SDRs at the same time, each with its own decoders. This is now FoxSDR's main screen.

The second update is a map that can accept multiple inputs from multiple decoders, allowing users to plot various data streams such as ADS-B, AIS, amateur high-altitude balloons, and more on a single map.

The third update is that Linux x64 builds are now published, although they are noted to still be in development. An Android arm64 build has also been released in alpha form. To access this, users will need to sign up to test.

The final update adds a new radar sweep feature, which locates the positions of air-traffic radars around you by listening to 1090 MHz. The author explains:

Secondary surveillance radars rotate and interrogate aircraft transponders as their beam passes. Aircraft that broadcast ADS-B also report their own position, so every reply they give reveals where a radar was pointing at that moment. Radar Sweep collects these replies over hours and works out each radar's location, rotation speed and direction on its own. It then draws bearing lines towards aircraft that answer the radar but broadcast no position, and marks a position where two radars' lines cross.

It is the same idea as PlanePlotter's Beamfinder, except that Radar Sweep finds the radar sites itself instead of being given them. It is not affiliated with PlanePlotter or its authors.

In testing on a 12.8-hour recording, it confirmed two radars, each within about 5 km of a published airfield position. Bearings to held-out aircraft had a median error of 0.3°.

You need a 1090 MHz antenna, an SDR running at 2 MS/s or more, and a few hours of traffic. Radar Sweep remembers the radars it finds and never reveals your location.

It is available free to FoxSDR users in the United States.

The author also wanted to share an upcoming feature, which is the GUI builder, which will allow you to customize your own GUI.

AI Disclaimer: wonderingStars describes their company as a human-gated AI company, and FoxSDR is AI coded.

October 1, 2026

RF-Traffic-Monitor: Track Aircraft, Ships, Drones and Radiosondes in One Program

Thank you to Stefanos (Steeod) for sharing a new program he created, "RF-traffic-monitor." Stefanos created this program because he initially wanted to install adsb.im (an ADS-B feeder image that also tracks ships, radiosondes, and ACARS/VDL2/HFDL) on Windows 10, but was unsuccessful in doing so, as adsb.im is written for Linux machines.

So, to get around this, Stefanos decided to fire up ChatGPT to write his own similar Windows program. The end result was RF-traffic-monitor, which is capable of tracking aircraft, ships, and radiosondes using an RTL-SDR or HackRF. It can also use the SDR to decode ACARS, VDL2, and HFDL. With a compatible WiFi adatper the software is also capable of tracking drones via Wi-Fi Remote ID.

AI Disclaimer: The author notes that this program was written by ChatGPT.

September 29, 2026

Echo Pro: KiwiSDR, OpenWebRX, WebSDR and FM-DX iOS Browser App now with Live Transcription and Translation

Back in April we posted about the release of Echo, a free iOS app designed for browsing global web-based KiwiSDR, OpenWebRX, WebSDR, and FM-DX software-defined radios. Mark, the developer of Echo, has written in to us again and wanted to share news about the release of the Pro (paid) version of Echo.

Echo Pro adds several features such as recording, on-device transcription and translation, iCloud sync, and the ability to access recordings across Apple devices. The transcription and translation service may be quite interesting, as it allows you to record an entire foreign radio program to text, and translate it to your language for later reading.

Echo Pro costs either US$4.99/month or US$39.99/year. More information about the app is available at echosdr.com.

September 29, 2026

RTL-SDR Pager: Android App for Receiving and Decoding POCSAG and FLEX Pager Messages

Thank you to Christian from ebcTech.eu for writing in and sharing with us the release of his new Android app called "RTL-SDR Pager" (Google Play Store link). The app is designed to work with an RTL-SDR dongle connected to the Android device. It is capable of decoding POCSAG and FLEX messages. However, Christian notes that he hasn't been able to test FLEX decoding so far because there are no FLEX channels in his area, so he would be interested in any feedback on this.

The app also provides push alerts, allowing you to monitor for a specific RIC or keyword and allows you to save channel lists.

The app offers a free demo that allows up to 50 messages. Upgrading to unlimited messages costs $3.99.

Screenshots of the ebcTech RTL-SDR Pager App

September 28, 2026

Turning a Smartphone’s Speaker Amplifier into a Silent Intentional VHF Morse Transmitter

Thank you to Efe Işık (TA1EEI) for writing in and sharing with us his open-source project showing how to turn a modern Android smartphone’s internal Class-D speaker amplifier into a silent, intentional VHF Morse transmitter. Efe writes:

By pushing inaudible 21 kHz full-amplitude PCM audio via Android's AudioTrack, the amplifier's PWM switching circuit radiates near-field RF harmonics into the 144 MHz (VHF) band. The signal is strong enough to be received in AM mode on common SDRs and BK4819-based handheld transceivers (such as the Quansheng UV-K5) simply by placing the antenna near the speaker grill.

Everything is open-source, requires zero Android permissions, and includes instructions on receiver setup and frequency alignment.

With the software running on the Android device, simply use an SDR or handheld radio to look for the signal in the 144 - 146 MHz region. Increasing the volume can help increase transmission power.

This reminds us of the TrojPix project, a more sophisticated method that uses a program on a PC to imperceptibly modulate pixels on a screen, effectively turning video cable/screen EMI into an air-gapped data transfer path.

September 28, 2026

Elektro-L3 Now Drifting West to 14.5°W: L-Band xRIT Could Return to Western Europe in October

Back in May, we posted about how Russia's Elektro-L3 geostationary weather satellite was expected to move from 76°E to 14.5°W, which would finally bring an unencrypted L-band LRIT/HRIT downlink over Western Europe. Thank you to RTL-SDR reader tec_msat for writing in and letting us know that the move now appears to be underway.

tec_msat writes that Elektro-L3 went quiet around September 10. Updated TLEs on September 13 then showed the satellite drifting west at roughly 1.7 degrees per day. Around September 20, its orbit was circularized, making it drift faster at around 3.1 degrees per day. At its current speed, it should reach 14.5°W around October 12. Based on Elektro-L5's commissioning timeline, test transmissions could begin within days of arrival.

Elektro-L5, launched in February 2026, has now been successfully commissioned at L3's old 76°E slot, which covers Asia, the Middle East, and parts of Russia and Australia. It has been transmitting GGAK, LRIT and HRIT, as well as X-band RDAS. With L5 taking over the eastern slot, L3 will replace the aging Elektro-L2 at 14.5°W. L2 never provided LRIT/HRIT from that position due to power supply issues, although the original Elektro-L1 did when it was stationed there.

Roscosmos noted in August, when announcing L5's commissioning, that L3 may be moved to 14.5°W. However, there has been no official announcement from Roscosmos that the relocation has started, so the drift observations currently come from amateur TLE tracking.

Once commissioned, L3 should once again make geostationary L-band weather imagery at 1691 MHz available to users in the UK, Ireland, Iceland, Portugal, Spain and western France. tec_msat also speculates that the signal may be stronger over Europe than it was from 76°E (potentially due to better elevation angles), making xRIT reception even easier.

If you're in the coverage area, now might be a good time to get your dish, feed and LNA ready. SatDump is the best software tool to use for reception and decode and our Discovery Dish with L-Band feed and RTL-SDR Blog V3 is a great starting point for hardware.

Expected Elektro L3/L4/L5 global coverage from mid-October 2026.