Over on his YouTube channel Tech Minds has recently released a new video demonstrating how to use an RTL-SDR portably via an Android tablet and an OTG cable. In the video he goes through the various Android software options available including general receiver software such as RF Analyzer (free) and SDR Touch (£5.99) as well as AVARE ADSB for ADS-B aircraft reception. He goes on to demonstrate each program in action.
In political news 75 year old Buffalo protestor Martin Gugino has been generating controversy due to a video of him being pushed to the ground by a police officer, then subsequently lying motionless while bleeding from the head and being ignored by other officers.
Recently US president Donald Trump tweeted about a video news report by "One America News" (OAN) indicating that Gugino may have been trying to scan police with a "capture scanner". Whilst talking about the capture scanner they show an image of an RTL-SDR dongle and Android phone running the SDR Touch software. OAN go on to say that these capture scanners are designed to "skim microphones" in order to capture police communications, and are a tool commonly used by Antifa. Credit to @hackerfantastic for initially tweeting about the RTL-SDR being featured in the video.
Trump's tweet reads "Buffalo protester shoved by Police could be an ANTIFA provocateur. 75 year old Martin Gugino was pushed away after appearing to scan police communications in order to black out the equipment @OANN
I watched, he fell harder than was pushed. Was aiming scanner. Could be a set up?".
We're not entirely sure where this theory from OAN came from as there is no need to get so close in order to listen to police radio communications, since if unencrypted, they can be listened to from anywhere in the city. It's also unclear as to what microphones police would be using, and how these could be "skimmed" with an RTL-SDR. As for blacking out the equipment, an RTL-SDR cannot transmit so it would be impossible to use to jam the radios. An illegal jammer could be used after scanning, but police frequencies are already well known anyway, and there would be no need to scan for them so close even if low power comm links were used.
The video also shows that he appears to be filming police badge numbers with his phone before he was pushed, so it is unlikely that he was using an RTL-SDR and running SDR Touch at the same time as the camera app. No cables, antenna or dongle can be seen in the video either.
In the past we have seen a Slovenian researcher almost jailed for performing University research with an RTL-SDR, and a UN expert arrested for possessing an RTL-SDR in Tunisia. So this is a timely reminder to be careful as police and media do not always understand what an SDR is.
EDIT: Please note that this is not a political post or blog. We only post it to highlight the severe lack of understanding that can surround SDR and our technical hobbies. Comments inciting violence against protestors or anyone are NOT OK, and will be removed. Please keep discussions technical and civil in nature.
Over on YouTube user 2e26tenW has uploaded a video showing reception of the second harmonic of an NFC polling signal with his RTL-SDR. NFC stands for “Near Field Communication” and is a technology that enables smartphones and other devices to communicate with one another and some smart cards simply by bringing the two devices together.
In his experiment he uses a Nexus 7 tablet to poll an NFC enabled transportation card. As the RTL-SDR cannot receive the NFC frequency of 13.56 MHz directly without an upconverter or hardware or software direct sampling modified dongle, 2e26tenW instead tunes to the second harmonic at 27.12 MHz which allows him to receive the signal.
SDR Touch, the popular Android based software defined radio software for the RTL-SDR has been updated to version 2.0. This new version is a complete rewrite with many optimizations listed below.
- 100% rewritten from scratch
- Improved reception sensitivity and quality
- Optimized engine
- GUI overhaul (Landscape mode, more flexible)
- 16 bit audio
- FIR filtering
The author also writes that the rewrite allows for new features coming out in the future such as adjustable bandwidth, FFT size, plugins and a separate GUI for in-car use. SDR Touch is available from the Android Play store.
There are now dozens of software defined radio packages that support the ultra cheap RTL-SDR. On this page we will attempt to list, categorize and provide a brief overview of each software program. We categorize the programs into general purpose software, single purpose software, research software and software compatible with audio piping.
If you know of a program that is missing please leave a comment in the comments section at the bottom of the page.
13/02/2014 - Added Sodira, gr-wmbus, rtlsdr-waterfall, QTRadio, multimon, sdrangelove, lte-scanner, rtl_tcp, rtl_sdr_FS20_decoder.
17/02/2014 - Updated the Linrad description.
28/04/2014 - Added Modesdeco and Trunk88.
30/05/2014 - Added RTL Panorama, RTL SDR Panoramic Spectrum Analyzer, Chrome Radio Receiver, SeeDeR, DAB Player, RTL SDR Installer, PD/Max Wrapper, SDRWeather, LTR Analyzer, softEOT/softDPU and ScanEyes.
26/07/2014 - Added PiAware, OOK-Decoder, rtl_fm_python, rtl_power heatmap viewer, RTL Bridge, threejs-spectrum, CANFI Software, PNAIS, FLARM Decoder, Xastir, RTLSDR-Airband, SDRTrunk.
13/11/2014 - Added Touchstone, RFAnalyzer, RTL1090 XHSI Interface, Parus Decoder, PlotRTL1090, LRPT Decoder.
05/02/2015 - Added rtl_tool_kit, CubicSDR, OregonWeather, FreqWatch.
15/04/2015 - Added ADSBox, YouSDR, FlightAware Flight Feeder, Frequensea, Track your flight EUROPE, QSpectrumAnalyzer, Doppler & Demod, Redsea, rtl_heatmap, gr-gsm, driveby, SDRecord.
23/12/2015 - Added Remote rtl_udp, AISRec, dump978, AISDeco2, SDRrecorder, OpenWebRX, dsame, RTL-Widespectrum, rtl_ais, rtl_gopow, ham2mon, rtl_ais_android, inmarsatdecoder, spektrum, qtcsdr, rtl_power_fftw, JAERO, GNSS-SDRLIB, SVxLink.
8/09/2017 - Added inspectrum, gr-isdbt, telive, tetra-listener, gr-iridium, SDRuno, luaradio, rx_tools, kukuruku, chronolapse, cloud-sdr, natpos, d3-waterfall, SDRDue, gqrx-ghostbox, ships, rtlmic, tsl-sdr, universal radio hacker, dumpvdl2, re-dected, aerial-tv, questasdr, welle.io, spyserver, dspectrumgui, atcsmonitor, NRSC5 HD Radio Decoder, leandvb, imsi-catcher, block stream receiver, salamandra, deinvert, RS.
6/11/2017 - qradiolink
15/06/18 - Zeus Radio
11/01/19 - SCEPTRE
13/01/20 - VDLM2DEC, Blockstream Satellite, TempestSDR, rtlsdr-wsprd, rtl_map, Radwave, radiosonde_auto_rx, XRIT Decoder, SATNOGS, SigintOS, RadioCapture, EMI_Mapper, xrit-rx (KOMSAT 2A), RTLion, WSJT-X, noaa-apt, rtlSpectrum, fingerprinting_radios_w_ML, mySdrPlayback, QO-100_SSB-WebSDR_DATV-WebSpectrum, goestools, SigDigger, Tekmanoid EGC, Scytale-C, PEPYSCOPE, iridium-toolkit, Electrosense, ORBCOMM-receiver, r2cloud, coole-radar, vor-python-decoder, IridiumLive, radio_analyser, DSDPlusUI, retrogram-rtlsdr, vortrack, rtl_power-fm-multipath, glrpt, Spektrum SV Mod, gammaRF, SegDSP, rtl-ultrasound, radiosondy.info, OP25, RS41 Tool, TETRA Trunk Tracker, meteor_demod, FreqShow, rtl_tcp SDR, PLSDR, SDR Receiver, Echoes, rtlmm, FM2TXT, cnn-rtlsdr, Meteor Logger.
General Purpose RTL-SDR Software
We define general purpose SDR software as programs that allow the RTL-SDR to work like a normal wideband radio receiver.
SDR# (Windows) (Free)
SDR# (pronounced "SDR Sharp") is the most popular free RTL-SDR compatible software in use at the moment. It is relatively simple to use compared to other SDR software and has a simple set up procedure. We have a full overview of the installation procedure on our Quick Start Page. SDR# is designed to be use with the $199 Airspy SDR, but works just fine with the RTL-SDR.
SDR# is a simple to use program that also has some advanced features. It has a useful modular plugin type architecture, and many plugins have already been developed by third party developers. The basic SDR# download without any third party plugins includes a standard FFT display and waterfall, a frequency manager, recording plugin and a digital noise reduction plugin. SDR# also decodes RDS signals from broadcast FM.
HDSDR (Windows) (Free)
HDSDR is based on the old WinRAD SDR program. HDSDR supports the RTL-SDR through use of an ExtIO.dll module. To install HDSDR, download the program from the link on the main HDSDR page, then to use the RTL-SDR you will need to download the ExtIO_RTL2832.dll file an place it into the HDSDR folder. When opening HDSDR, select the newly copied ExtIO_RTL2832.dll. The other dlls that come with HDSDR will not work with the RTL-SDR, even though they have RTL-SDR in their filename. The official installation instructions can be found here.
Along with a FFT display and waterfall, HDSDR has some extra advanced features. Users will also find an Audio FFT and waterfall display on the bottom of the screen. The output audio can also be bandpass filtered by dragging the filter borders on the display. Bandpass filtering the audio can really help clean up a noisy signal. The audio processing also supports placing of notch filters either manually or automatically. There are also noise reduction and noise blanker features and an automatic frequency centering algorithm which will automatically center the signal, so you don't need to click exactly in the center of a signal. Traditional ham radio users will also enjoy the S-units signal strength meter and the built in frequency manager.
SDR-RADIO.COM V2/V3 (Windows) (Free)
SDR-RADIO.COM V2 and the newer V3 is a popular SDR program with many advanced features. As such is it a fair amount more difficult to learn and use compared to SDR# and HDSDR. Be sure you install version 2 and not V1.5 as only V2 has RTL-SDR support.
Once sdr-radio is installed, to get it working with the RTL-SDR you will need to compile or download three .dll files (SDRSourceRTL2832U.dll, rtlsdr.dll and libusb-1.0.dll) and place them into the sdr-radio folder. To compile your own dlls see the instructions here, otherwise download the dlls directly from the bottom of this link. If the dlls were placed in the correct folder you will be able to add your RTL-SDR as a receiver by clicking on the +Definitions button, and then finding and adding the RTL SDR (USB) option under the search drop down menu.
Like HDSDR, not only does sdr-radio have a RF FFT signal and waterfall display, but also an optional audio spectrum FFT and waterfall display. Built in are also several DSP features like a noise blanker, noise reduction filter, notch filter and squelch options. The EMNS noise reduction filter is particularly good at automatically cleaning up and clarifying voice signals.
To add to the feature list, sdr-radio also has built in PSK, RTTY and RDS decoders, and also comes with a satellite tracker. Furthermore, sdr-radio V2 (not V3 yet) has an excellent remote server which will allow you to easily set up and connect to a remote RTL-SDR server over a network or the internet. Finally, sdr-radio is capable of listening to up to 6 signals in the same chunk of visible spectrum at a time.
The Android based SDR program SDRTouch has been officially updated to version 1.7. News comes via this forum post. This looks to be a major update which significantly improves audio quality and performance. The new features are listed below.
- FM is now in STEREO
- New audio recording feature for PRO users
- Improved reception and audio quality. All filters were tested for quality and all bugs discovered were removed.
- The multi-threading logic was completely rewritten. Now it’s faster than ever before.
- Audio is now using NDK.
- PPM correction, audio gain setting
- A lot of bug fixes and UI enhancements
- Experimental x86 support
The programmer of the Android based software defined radio app SDR Touch has released a public beta of version 1.7. The programmer writes that the new features include
New multi-threaded core, native audio support, experimental x86 support is included as well. Although most changes are under the hood (the release is build for performance boosts), probably the most obvious non-performance enhancement is FM STEREO.
If you intend to install the beta you will need to first uninstall your existing version of SDR Touch, which will cause you to loose any presets you may have set. The programmer warns that this version may be unstable as it is in beta.
You can download the beta from http://sdr.martinmarinov.info/
Wavesink is a new SDR Android App, which allows your RTL2832U based dongle to receive FM radio with RDS, Digital Audio Broadcast Radio (DAB) and VHF band Digital Radio Monodial (DRM+). DAB+ support is also to be released by next week, and a station memory will also be added in a future release.
The app is currently in beta development, and only the trial version is released, which will allow you to use the app for 5 minutes at a time. They indicate that the commercial version will be out soon.
To use this with your Android device, you will need a USB OTG (On the Go) cable, and your device must support USB host mode, which most Android devices above 3.1 should support.
I gave the app a quick spin in FM mode, and found that the interface was a little clunky, but the app worked fine, and the FM and RDS signals were decoded correctly.