Tagged: airspy

OpenWXSDR: A Streamlined Automated Multi-Sonde Decoder for Raspberry Pi with RTL-SDR or Airspy

Thank you to Mike (DL2MF) for writing in about the release of OpenWXSDR, a new open-source Python framework that turns one or more RTL-SDR dongles or Airspy SDRs into a fully automated radiosonde ground station running on a Raspberry Pi 4/5 or Linux x86 machine.

If you are unaware, a radiosonde is a lightweight instrument package typically carried by a weather balloon to collect atmospheric data, including temperature, humidity, pressure, and GPS position. It transmits this data back to the ground via radio signals. Using an RTL-SDR or another software-defined radio (SDR) along with appropriate decoding software, hobbyists or researchers can receive, decode, and visualize these signals. Radiosondes are typically launched by local meteorological agencies in many cities worldwide at least twice per day.

OpenWXSDR continuously scans the 400-406 MHz meteorological band, automatically identifies balloon transmissions using DFT correlation analysis, and spawns dedicated rs1729 decoder subprocesses. Supported sonde types include RS41, RS92, DFM06/09/17, M10, M20, iMet-54, LMS6, and MRZ.

The software also supports multi-sonde and multi-SDR. While one dongle scans for new signals, others simultaneously handle active decoding sessions. Decoded telemetry can be submitted in parallel to SondeHub v2 and to OpenWX.de via MQTT (with optional TLS), and as Horus-compatible UDP JSON datagrams for local tools like SondeMonitor. A built-in Flask and Leaflet web interface shows live positions, flight tracks up to 20,000 points, PTU sensor readings, and signal metrics, with most settings editable from the WebUI during operation.

OpenWXSDR Web Interface
OpenWXSDR Web Interface

P25-Survey: A Tool for Scanning and Logging P25 Control Channels with an SDR

Over on GitHub, programmer blantonl has released p25-survey, a Python tool that scans a frequency range with an RTL-SDR, Airspy or HackRF and identifies any P25 control channels present. For each one found, it logs the WACN, System ID, NAC, RFSS ID and Site ID, the full IDEN_UP band plan, neighbor sites with resolved frequencies, and signal quality metrics including RSSI, BER and decode rate.

The tool also has an optional RadioReference cross-reference mode that annotates results with the RR system name and site description, flags frequency offsets versus the database, and generates a Markdown submission report for data not yet in RadioReference. An auto-gain feature sweeps gain values on each confirmed control channel and recommends the optimal setting for your SDR and location based on BER.

P25 Survey Tool
P25 Survey Tool

Stream1090: A New Approach to ADS-B Demodulation Using CRC-Based Framing Instead of Preamble Detection

Over on GitHub, Martin (mgrone) recently released stream1090, a new open source C++ Mode-S demodulator that takes a fundamentally different approach to finding aircraft messages. Rather than searching for the traditional preamble pulse sequence as dump1090 and readsb do, stream1090 continuously maintains shift registers and identifies valid messages based on their CRC checksum. In busy airspace where preambles can be corrupted by overlapping signals, this approach theoretically cannot miss a message as long as the data itself is intact. Since the CRC is always being computed, it can also be used for single-bit error correction.

The software supports both RTL-SDR and Airspy dongles. It's lightweight enough to run on a Raspberry Pi Zero 2W. Stream1090 is a demodulator only, designed to pipe output into readsb or dump1090-fa via socat, slotting into your existing ADS-B stack as a drop-in replacement for the demodulation stage.

If you have an ADS-B station in a high-traffic area, let us know if Stream1090 increases your message rate! There is also a discussion about it on FlightAware, where many people have indicated that they are getting great results.

Stream1090 GitHub Readme
Stream1090 GitHub Readme

Receiving the Artemis 2 S-Band Carrier With a Wi-Fi Dish and Airspy R2

Thank you to Simone Spadino for writing in and sharing how he received the S-band carrier signal from the Artemis 2 Orion capsule from his home in Italy, using a simple one-meter Wi-Fi grid dish, an Airspy R2, an LNA, a filter, and a downconverter. Simone notes that his results show it is possible to receive the Artemis carrier signal with a small dish.

Artemis 2 may have already returned to Earth safely, but there are future missions planned for 2027 and beyond, so Simone's write-up serves as a great place to get yourself ready to receive those future missions.

Simone's write-up notes that perfect tracking with a rotator wasn't required because the Wi-Fi dish had a beamwidth of about 11°, so he was able to manually orient the dish every 10 minutes using an Android smartphone. On the first night, he achieved a carrier SNR of 5.5dB, and on the second night, 6.5 dB.

Artemis S-Band Carrier Received with Wi-Fi Grid Dish
Artemis S-Band Carrier Received with Wi-Fi Grid Dish

Khanfar Software: Analog Radio Hunter

Recently, M. Khanfar released a new free program, "Analog Radio Hunter," described as a "professional RF analysis and monitoring application built around GNU Radio and Fosphor." The software currently supports RTL-SDR, Airspy, and HackRF. Khanfar writes:

Analog Radio Hunter is a professional RF analysis and monitoring application built around GNU Radio and Fosphor.

It is designed to scan large RF spans, quickly lock onto active signals, and monitor analog transmissions with NFM, AM, or WFM audio demodulation.

  • Real-time FFT + waterfall spectrum display
  • Fast scan with dwell, pause-on-squelch, and skip-ignored channels
  • Detection list with hits, timestamps, and smart deactivation
  • Favorites profiles with monitor and favorites-only scan modes
  • Built-in recorder with auto-record and event log
  • Dedicated WFM broadcast receiver with presets
  • Multi-SDR device support (RTL-SDR, Airspy, HackRF) with auto-detect and device switching
  • NFM and AM audio demodulation (in addition to WFM)
  • Peak-follow in span (auto-tune to strongest signal inside the current MS/s window)
  • Frequency list filtering to skip/mute ignored channels
  • Scan and detection profiles (save/load named presets)
  • PPM correction for RTL-SDR calibration
  • Spectrum interaction controls (cursor readout, click-to-tune, wheel step, drag-pan)
  • Recorder options (record when muted, timestamp/frequency in filename, beep on favorite)
  • WFM de-emphasis selection (50/75 µs) and preset management
  • Audio Output menu with refresh (route audio to speakers, VB-Cable, or USB output)
  • Signal Stability Filter with Min Open + Grace timing and per-target routing
  • Histogram IQ Rec with live IQ follow controls and inspectrum integration
  • Auto Squelch Calibrate (noise floor + margin) for faster field setup
  • Smart Deactivate dual-layer logic (time-based + hit-rate busy rule)
  • Favorites cooldown auto-reactivation for busy channels
  • Favorite TX tones (Tone 1-9), edge selection, and tone test buttons
  • Learning Mode hover guidance for faster onboarding
  • Status bar live metrics for Last, Active, Favorite, Peak SNR, and Level
Unique scanning and detection approach: Traditional sweep scanners only see the center frequency they step to. Analog Radio Hunter monitors an entire chunk of spectrum at once and reacts to peaks inside it. That is a major differentiator.
 

High-Impact Capabilities

  • Wide-span reactive scan engine that hunts activity across a full chunk, not one center point at a time.
  • One-click IQ capture and histogram visualization with follow and idle flow controls.
  • Carrier-resilient channel management using Smart Deactivate + favorites cooldown logic.
  • Field-ready setup speed using Auto Cal squelch and persistent live status metrics.
  • Operator-selectable audio routing to speakers, VB-Cable, or USB audio output devices.
  • Operational clarity from GUI color heatmaps, scan debug reasons, and learning-mode tips.

Signal Stability Filter: Logic and Tuning

  • Purpose: reject short squelch flicker and noisy open/close chatter before actions trigger.
  • Min Open (ms): raw squelch must stay open this long before stable-open is accepted.
  • Grace (ms): stable-open is held briefly after raw close to avoid tiny dropouts.
  • Apply targets: Detection, Rec+Alerts, Scan Hold, and optional Audio Out gating.
  • Start values: Min Open 150-250 ms, Grace 40-80 ms, then tune by channel behavior.

Like his other software, which we previously covered, it is free but not open source. Anti-virus programs may flag the software as suspicious due to heuristics. We believe this to be a false positive, but as with all software that isn't open source, we recommend being highly suspicious and only run it in a sandboxed environment like a VM to be sure.

M Khanfar Analog Radio Hunter
M Khanfar Analog Radio Hunter

Mykola: A New Fast Multichannel Scanner Application for RTL-SDR, Airspy and HackRF

A new multichannel SDR scanner application called 'Mykola' has recently been released by a Ukrainian programmer with the same name as the application. A scanner application allows users to scan a much wider bandwidth than the SDR's instantaneous bandwidth, while automatically searching for active signals.

Mykola advertises extreme scanning speed abilities, adaptive noise floor, and simultaneous demodulation of 3 channels (20 in the paid pro version). It currently supports RTL-SDR, Airspy R2, and HackRF SDR devices. Some of the other features include automatic normalization of the noise floor, audio panning, and support for Windows and macOS.

The application is free, but a pro version will be available in the future, which enables additional features such as stored channel scanning, recording, voice activation, CTCSS/DCS decoder, SDR migration, channel editor, and a base channel set. The pro version is not yet available, and pricing has not been announced. 

Features of the Mykola Scanning Software
Features of the Mykola Scanning Software
Mykola Scanner Interface
Mykola Scanner Interface

SDRSharp Frequency Manager Python Application

Thank you to Argilli Marco (IU4HMY) for writing in and sharing with us his Python application called "SDR# Frequency Manager 1.0.1" for managing frequency lists in SDR#. SDR# is a popular free SDR program commonly used with RTL-SDR and Airspy dongles. Argilli writes:

SDR# Frequency Manager is a Python application designed to simplify the management and editing of frequency lists used by SDR#. The software allows you to open, edit, and save SDR# XML frequency files in a clear and structured interface.

The application is free but closed source and available on his website.

SDR# Frequency Manager Python Application

DSDPlus Public Release Updated & Fast Lane Changes

The team behind DSDPlus has recently uploaded a new public release version 2.547. The last public release was version 1.101, released several years ago. Up until now, only DSD+ Fastlane customers have had access to the new version.

The new version adds new programs like FMP, which can be used to receive the FM signal from an RTL-SDR, Airspy or SDRplay SDR and transfer it to DSD+ over TCP. Previously, a program like SDR#, or SDR++ would have to be used along with audio piping software like VB Cable. 

Also introduced are numerous enhancements, including a single-receiver trunk-tracking mode that eliminates the need for dual SDR setups, a site loader GUI for rapid tuning and system selection, significantly expanded digital protocol support such as full P25 Phase II TDMA voice following, encryption algorithm and key ID detection, and GPS/AVL location and mapping capabilities. Hardware integration has also improved with features like bias-tee control for RTL-SDR Blog dongles, serial-targeted device selection, and smoother TCP-linked operation between DSD+ and FMP components.

The full list of changes can be found in the "Notes.txt" file in the DSDPlus zip file. The Radio Reference Wiki also has a summarized changelog.

The team also notes that they are now closing new signups to the DSD Fastlane program. FastLane was a program that allowed users to pay a small fee to receive the latest updates. They note that the program will remain active for users who have already signed up.

DSD Plus V2 Public Release with FMP24
DSD Plus V2 Public Release with FMP24