Over on his YouTube channel Corrosive from the SignalsEverywhere YouTube channel has uploaded a tutorial that shows how to set up ADS-B aircraft tracking with an RTL-SDR, dump1090 and Virtual Radar Server. The decoder software is dump1090 which is a multiplatform command line tool, and Virtual Radar Server is a Windows and Linux compatible program that is used to display the data on Google maps.

ADS-B is used as a more accurate and modern replacement for traditional aircraft radar. Instead of relying on radar reflections, ADS-B simply transmits a radio signal containing plane data such as GPS location, speed, and identification codes. Other aircraft can use this data for collision avoidance, and ground control use it for traffic management. Setting up your own RTL-SDR based ADS-B receiver allows you to see and track on a map almost all the aircraft currently flying in your area.

Over on his YouTube channel SignalsEverywhere, Corrosive has uploaded a new video about setting up a KerberosSDR for direction finding. KerberosSDR is our new 4-input Coherent RTL-SDR that was crowdfunded on Indiegogo, and has now shipped to all backers. With KerberosSDR applications like direction finding and passive radar are possible. If you're interested, there are still about 70 units available in this batch. After that a second batch will be available in a few months.

In the video he goes over the full set up procedure, from setting up his chosen computing platform (a Raspberry Pi 3) to connecting up the KerberosSDR, connecting to it's web interface, calibrating, setting up the antennas, and then demonstrating some direction finding with four whip antennas on his car and a HackRF used as a signal source.

Over on Reddit freelance investigative journalist Emmanuel Freudenhal has put up a very interesting post about how he is using ADS-B tracking to keep an eye on the travel habits of dictators around the world. If you were unaware, ADS-B is a signal transmitted by aircraft which contains aircraft ID info, and data such as speed, altitude and GPS location. Websites like ADS-B Exchange aggregate ADS-B data from volunteer ground stations that are running (mostly) RTL-SDR dongles. Emmanuel notes that by watching the movements of aircraft registered to dictators, it is possible to keep an eye on their travel habits.

One story that Emmanuel has written using this data is a piece on Paul Biya, Cameroon's president. His article discusses how Paul Biya is often seen in Geneva Switzerland, away on private visits. In a comment, Emmanuel notes that since his story ran, Paul Biya has almost stopped travelling to Switzerland.

Emmanuel has also been running a Twitter bot that uses ADS-B data to automatically tweet when a dictator aircraft is detected at Geneva airport. A list of known dictator aircraft is kept on a publicly accessible Excel file.

Now he is hoping to expand his tracking operation, and is asking for more people to feed the ADS-B Exchange aggregation website. ADS-B Exchange is the site recommend to feed because it is the only ADS-B aggregation website that does not censor any aircraft. Other aggregation sites such as Flightradar24 and FlightAware have come under scrutiny in the past for their willingness to upon request censor and block the tracking of military/political aircraft and private jets owned by several companies. In particular several aircraft owned by dictators are reportedly censored. However, the counter argument is that not censoring aircraft may result in ADS-B tracking eventually being made illegal, or that costly legal suites may be brought against ADS-B aggregation companies.

On the Reddit post Emmanuel writes:

I'm a freelance investigative journalist (www.emmanuel-freudenthal.com / @emmanuelfreuden). I'm getting into SDR/ADSB and very glad I found this group because I need your help to track aircrafts!

With a colleague, we started a project to look into the travels of dictators around the world. It's an evolution of a Twitter bot (https://twitter.com/GVA_Watcher) started a few years ago. This bot tweets every time an aircraft owned by a dictatorship lands or takes off at the Geneva airport, Switzerland. And dictators visit Geneva, a lot. There's secretive banks and good healthcare, enjoyed by Algeria's departing president or Cameroon's president Paul Biya.

We want to expand this project to all of the world's airports. See our place-holding website: https://dictatoralert.org(which will get expanded soonish). To do so, we've partnered with ADSB-Exchange, which as you probably know, is the only website that doesn't censor flights. Usually the planes owned/chartered by dictatorships don't show up on flightaware or flightradar24 (anyone can asked to be removed). Some planes also don't share their GPS coordinates (e.g. Mode S) and so they don't show up.

In addition to the Dictator Alerts, we'll also use the data to do investigations into dictatorships, human rights violation and corruption.

The idea is to allow everyone to keep tabs, so the data will be available publicly, via Twitter bots and on a dedicated website (with e.g. a page per dictatorship and per airport).

To succeed, we need a lot more antennas! So, it'd be great if you could feed ADSB-Exchange. You can do that in addition to feeding other services. See how to do it here: https://www.adsbexchange.com/how-to-feed/ If you want to feed, please contact me on emmanuel.freudenthal@gmail.com, my twitter DM are open. It's quite important that you contact me before feeding, so that we also capture aircrafts that don't share their GPS coordinates.

That also means, you'll be able to see ALL of the data that you're collecting online.

What do you think? Would you be keen to participate? Any questions?

Your feedback is very welcome, i'm still learning!

Best,

Emmanuel

Other stories of interest: A similar story we ran last year was about tracking police and military aircraft at the G7 summit with an RTL-SDR, and three years ago we ran a story about tracking World Economic Forum Attendees with an RTL-SDR.

Thank you to Dimitris for submitting his article on creating an RTL-SDR based EMC probe. An EMC probe is a device that can be used to detect electromagnetic interference leaking from areas on electronic devices. For example an electronic PCB might have problems with RF leaking into other components. With the probe you could determine where the leak is coming from.

To create the probe he uses a 30cm semi-rigid coax cable and an RTL-SDR dongle. The semi-rigid coax is cut in half, the center conductor stripped back, then looped around on itself and soldered to the shield. Dave from EEVBlog did a video on this previously which is what inspired Dimitris. The next steps are simply to connect the probe to an RTL-SDR, put it into direct sampling mode and probe around for signals. Note that an RTL-SDR with direct sampling like our V3 model, or an RTL-SDR with upconverter is required to receive signals below 24 MHz.

His results show that he was able to successfully probe an OCXO oscillator, by seeing the 10 MHz signal in SDR#. The rest of his post goes on to discuss the limitations of this method, and compares it against professional EMC probes available on the market.

Corrosive from the SignalsEverywhere YouTube channel has recently released episode two of his new podcast. This episode is titled "Common SDR Mistakes and How to Resolve Them". In the podcast Corrosive discusses some tips like how to ensure that the gain on your SDR is set correctly, how to set the sample rate, how to optimize the waterfall display, and what antennas to use. Later he goes on to talk about our RTL-SDR Blog V3 dongles, and discusses some posts from our blog.

RadioCapture.com is a website run by Matt Mills that is capable of automatically capturing trunked radio communications from various agencies such as the emergency services and creating publicly accessible historical and live logs of the audio. This is a concept different to radio scanner streams, as all audio is logged and historical audio can be accessed easily at any time.

The system is based on SDR hardware such as the RTL-SDR. Currently Matt runs a receiver in Denver and captures Denver PD which can be listened to on the site without needing to log in. Once logged in (registration is free), other talkgroups available include various agencies in Colorado, New Jersey and Pennsylvania.

Recently Matt has put a call out for people to help support the site via Patreon. He notes that RadioCapture is currently run as a hobby, but with monetary support he hopes to be able to expand the site into a business and have receivers listening and uploading worldwide. He writes:

Hey! Thanks for supporting the continued operation and development of Radiocapture.com. This is a hobby project I've been working on this since late 2011. I'd like to turn it into a real business with your help.

Radiocapture.com is a software defined radio system I built that captures entire trunked radio systems. It demodulates and captures every call on every channel of one, or many systems.

A single RadioCapture server can capture hundreds of simultaneous voice transmissions and a bunch of sites, additionally it's designed in such a way that it can run across multiple computers. My biggest RF site uses 3 machines to capture 19 P25 systems, and easily hits more than 100 active voice channels recordings simultaneously every day.

Matt has also noted that if the site is able to become self-sustaining via Patreon, he hopes to also be able to bring out a RadioCapture kit consisting of 10-16 RTL-SDR dongles, hubs and cables which would allow anyone to easily capture and upload almost all trunked communications from their area. He also notes that at the time of writing:

RadioCapture has 701790271 unique recordings of 503779875 unique transmissions (some calls get captured on multiple transmitters) from the 21 systems that have been captured

If you're interested in talking to Matt about the site, you can also join his Rocket.Chat room at radiocapture.chat.

NAVigation with Indian Constellation (NavIC) (previously known as IRNSS) is an Indian navigation system consisting of 7 satellites in geosynchronous and geostationary orbits above India. It is intended for both public and military use, with a public resolution of up to 20m, and military resolution of up to 1m. After a few set backs, the satellite constellation was completed in April 2018.

Over on his blog Radiojitter, Priyasloka has put up a post showing how he was able to receive and decode the IRNSS/NAVIC satellites. To do this he uses an RTL-SDR with a GNSS antenna connected, and a modified version of the MATLAB GPS code found in this previous post, and in SoftGNSS. His post first goes through how he was able to decode and receive GPS, then goes over the technical details of the NAVIC signal, and then shows some result screenshots where he was able to determine his location with both GPS and NAVIC.

Priyasloka writes that he hasn't uploaded the modified code yet, but he plans to do so soon.

Over on his blog '19max63' has posted about his tests with a $2 Aliexpress low noise amplifier (LNA) and his RTL-SDR. The LNA is advertised as for boosting HDTV signals, but 19max63 has found that it does a decent job on other frequencies too. It can be found on Aliexpress for less than $2 including free shipping, by searching for "TV Antenna signal amplifier". One example listing is this one.

An LNA is useful to help lower the noise figure of a radio system which results in higher SNR values (especially at the UHF and higher bands), and can be used to overcome losses in the signal chain from components like coax cables and connectors. However, an LNA will not always help and when combined with strong in or out of band signals will make reception worse by causing overload and intermodulation products. Better quality LNAs have a low noise figure, and are able to handle stronger signals and not overload so easily.

Upon opening the cover, 19max63 found that the cheap LNA consists of a BFG425W transistor which should cover 40 MHz to 3 GHz, but may be band limited by the passive components. The BFG425W also has a max gain of 20dB at 2GHz and a noise figure of 0.8 dB at 900 MHz. 

In 19max63's tests, the LNA was able to improve his DAB radio (174 to 240 MHz) reception significantly, allowing him to receive several extra stations. His further tests also seem to show that it does a decent job at other frequencies from 137 MHz NOAA satellites to 1090 MHz ADS-B. Many of the comparison images do seem to show signs of overloading and intermodulation, but ADS-B in particular looks to be boosted quite nicely. So this looks like it might be a very cheap way to try and improve ADS-B reception.

Check out the his post for multiple SNR comparison images.

Recently Scanner School released episode 70 of their podcast, and on this episode they talk about various SDR topics with Corrosive from the Signals Everywhere YouTube channel. If you follow out blog, you'll know that Corrosive is a YouTuber that is consistently putting out high quality YouTube videos on a range of SDR and other radio related topics.

Scanner School is an online workshop that aims to help you get setup with an RTL-SDR based DMR/NXDN/P25 trunking system in four classes. They also have a weekly podcast. The description of this weeks podcast with Corrosive reads:

Corrosive has been working on his YouTube channel for about 4 years, and has a ton of videos on the SDR topic. If there is something that I am looking a trying when it comes to SDR, the first place I look is on Corrosive's channel.

Today we talk about some advanced SDR topics, both for receiving and transmitting.

While we talk about the more advanced topics of SDR today, I know we all have to start somewhere. If you are looking for online training to help you get started with SDR, check out our new Intro to SDR Workshop. This course will guide you though purchasing an excellent and affordable SDR to get started with.

Additionally, we will turn this SDR into a DMR, P25, and NXDN trunked receiver that can do more than your expensive scanner.

Over on YouTube and his blog user Charles Grassin has uploaded a short video and blog post showing how he's using an RTL-SDR EMI (electromagnetic interference) probe and OpenCV to create a visual EMI heatmap.

Earlier this month we posted about Dmitris' experiments in which he was able to create a home made EMI/EMC probe out of a loop of semi-rigid coax and an RTL-SDR V3. This type of probe is useful for determining what components or areas on a circuit board are emitting electromagnetic interference. EMI testing for PCBs may be critical for passing compliance tests.

Charles' project takes the RTL-SDR EMI probe idea a step further by combining it with OpenCV. OpenCV is an open source library of code for computer vision applications. With the EMI data generated by the RTL-SDR EMI probe, and a camera pointed at a PCB, Charles is able to overlay a heatmap on top of the visual image which reveals the EMI hot spots on a PCB.

The video below shows the EMI heatmap of an Arduino PCB being mapped out. His blog post shows some other examples like a keyboard and a hairpin RF filter. The code he's created is open source and available on his EMI_Mapper GitHub page.

Over on our YouTube channel we've uploaded a short video that gives a tutorial and demo of the KerberosSDR being used as an RF direction finding system in a car. If you weren't aware, KerberosSDR is our recently released 4x Coherent RTL-SDR which can be used for tasks such as direction finding and passive radar. KerberosSDR was successfully crowdfunded over on Indiegogo, and we have recently completed shipments to all backers. Currently we are taking discounted pre-orders for a second production batch on Indiegogo.

In the video we use a Raspberry Pi 3 B+ running the KerberosSDR image as the computing hardware. The Pi 3 is connected to a high capacity battery pack. It is important to use a high quality battery pack that can output 3A continuously as this is required for the Raspberry Pi 3 B+ to run without  throttling. The battery pack we used has multiple outputs so we also power the KerberosSDR with it.

Once powered up we connect to the KerberosPi WiFi hotspot, and then browse to the web interface page. We then tune the KerberosSDR to a TETRA signal at 858 MHz, perform sample and phase calibration, set the decimation and FIR filtering, and then enable the direction finding algorithm. At this point we enter the Android app and begin direction finding and logging our data.

After driving for a few minutes we stop and check the logfile and find that the majority of the bearing lines point in one direction. With this info, a drive in the direction of the bearing points to gather more data is performed. Once additional data was gathered we open the log file up again, and see where all the bearing lines cross. Where they cross indicates the location of the 858 MHz transmitter. The heatmap data also gives us a second confirmation that the transmitter is located where we think.

NOTE: Some of the features shown in the video like the heatmap, confidence settings and plot length settings are not yet released in the current version of the app. They will be released next week.

Full instruction on using the KerberosSDR are available at rtl-sdr.com/ksdr.

Recently several newspapers [CNA] [France24] [Guardian] [MEM] [HuffPostMG] have reported a story about a United Nations (UN) expert being arrested in Tunisia for having an RTL-SDR dongle. Dr. Moncef Kartas is a member of a UN panel of experts investigating violations of the UN arms embargo on Libya. 

On March 26, 2019 Kartas was arrested on his arrival in Tunisia on suspicion of spying for "unnamed foreign parties", and one of the key arguments being used against him is that he was in possession of and had used an RTL-SDR dongle. In the France24 article, they explain that he was using the RTL-SDR as part of his investigation for monitoring air traffic to Libya in an attempt to link flights against violations of the arms embargo. 

As Kartas' business in Tunisia was to present his findings on the arms embargo violations, other experts believe that the arrest is politically motivated, and that ownership of the RTL-SDR for espionage is simply being used as an excuse. However, while the investigation continues Kartas remains in Jail, and in Tunisia a charge of espionage could be punishable by death. As Kartas holds UN diplomatic immunity, and as Tunisia is a member of the UN, the arrest and detainment is seen as illegal.

We hope that Kartas is safe and will be released soon. If you want to keep an eye on his story, there is a Twitter account called "Free Moncef Kartas" @FreeMoncefK that appears to be posting news articles and tweets about his arrest.

Thank you to Happysat for writing in and noting that over on the Amsat-DL forums user Markro92 has uploaded a realtime Windows DVB-S demodulator with GUI. The demodulator works with the RTL-SDR, HackRF, SDRplay and PlutoSDR support is due to be added soon. Happysat notes the following: 

It can demodulate DVB-S and S2 signals with very low symbolrate on Es Hail-2 geosat on 25,9 East from the Wideband Transponder. So you do not need a modified lnb or modified satelitte stb :) Of course you can also see the amateur tv streams which people uplink theirself.

To see if there is any stream active one can visit the wideband WebSDR and above the stream the info is displayed which parameters in use (symbol rate and mode dvbs(2)) so you can adjust in the Demodulator program. Stream + Chat: https://eshail.batc.org.uk/wb/ .

The latest version of the software will always be always available at http://v.1337team.tk/dvb-s_gui_amsat.zip.

Thank you to Walter P. for writing in and sharing with us his conversion of an old analog boombox into a fully functional wideband software defined radio based on an RTL-SDR dongle and upconverter.

Inside the boombox Walter stripped away the analog circuitry and replaced it with a new LCD screen, Raspberry Pi, RTL-SDR, upconverter and an audio amplifier. Four rotary switches on top of the radio are used to control the frequency, demod mode and volume, and there is also a numerical keypad which can be used to enter the frequency directly. 5V and HF antenna connectors have been added to the side, as well as an upconverter enable switch on top. Walter also added a Spyserver mode to the software, which allows you to connect to the radio over WiFi with SDR#, although he notes that using the integrated Pi WiFi module seems to introduce noise on the speakers.

If you're interested in building a similar device, Walter has provided the full Python code and installation instructions for his build.

Edit 09 May 19: It was pointed out that the word "ghettoblaster" could be considered offensive in some cultures. We have changed the word in our article to "boombox" and apologize for any unintended offence.

Yesterday we posted about a real time Windows demodulator for receiving amateur TV DVB-S/S2 on Es'Hail-2/QO-100. Recently another YouTube user "M Khanfar" also submitted a video tutorial showing how to decode Es'Hail-2 DVB-S2 on Ubuntu with an RTL-SDR and the LeanDVB decoder.

Khanfar notes that although the LeanDVB decoding method is not real time, his tests show that the LeanDVB method is able to work with a much lower SNR signal compared to the Windows demodulator. The process is to simply capture an IQ file with GQRX, then run LeanDVB on the command line with the recorded IQ file. It will create a TS file that can be played in any media player.

His receiving setup consists of an RTL-SDR, 100cm dish, modified LNB and a home made bias tee that can switch his LNB between horizontal and vertical polarization.

Thank you to Godrey L for submitting his article/tutorial that shows us how to broadcast a DAB/DAB+ radio station using a LimeSDR and ODR-mmbTools. The LimeSDR Mini is a US$159 12-bit TX/RX capable SDR that can tune between 10 MHz – 3.5 GHz, with a maximum bandwidth of up to 30.72 MHz. ODR-mmbTools is an open source DAB transmission chain which is compatible with USRP and LimeSDR SDRs.

DAB stands for Digital Audio Broadcast and is a digital broadcast radio signal that is available in many countries outside of the USA. The digital signal encodes several radio stations, and it is considered a modern alternative/replacement for standard analog broadcast FM.

The tutorial is split into four parts. The first part simply explains what SDRs are and in particular discusses the LimeSDR and how it can be used with ODR-mmbTools. Part two discusses what hardware you need, and explains what each component of the ODR-mmbTools software does. Part three gets into the actual setup of the software on Linux. Part four finishes with actually transmitting the signal and decoding it with an RTL-SDR and the Welle.io DAB decoder.

The end result is a DAB radio station with three stations being broadcast.

EMWIN is an acronym for Emergency Managers Weather Information Network, and is a service for emergency managers that provides weather forecasts, warnings, graphics and other information in real time. EMWIN is broadcast from geostationary NOAA GOES satellites, and if you have a GOES SDR receiver setup it is possible to receive and decode EMWIN data.

However, if you don't want to set up a GOES receiver, KD9IXX writes on his blog how he investigated EMWIN and found that 24/7 dedicated EMWIN VHF repeaters are common around the US. Having found an EMWIN repeater in his area at 163.37 MHz he used the TrueTTY decoder and was able to successfully decode the 1200 baud 8-bit ASCII encoded signal and receive weather text information. He notes that VHF EMWIN is an excellent source of non-internet based weather data that could be useful to anyone requiring weather data in emergency circumstances.

Corrosive from the SignalsEverywhere YouTube channel has released a new episode of his podcast, this time discussing the topic "Is Software Defined Radio Illegal?". Recently we posted about the unfortunate arrest of a UN investigator in Tunisia. Reports from news agencies seem to indicate that a major factor in his arrest was his use of an RTL-SDR dongle for monitoring air traffic as part of his investigation on Libya arms embargo violations. Although it is suspected that other political motivations are at play.

In his podcast Corrosive tries to open a discussion on whether software defined radio (SDR) is illegal, since SDR receivers have the possibility to be able to receive, demodulate and decode almost any signal. He first focuses on mostly American FCC laws regarding scanners, but similar laws are likely to be in place throughout most of the western world. Later in the podcast he discusses transmit capable SDRs and how these are more likely to come to the attention of politicians.

Redditor [K3PWN] has recently released his project called “RTLion”. RTLion is a software framework for RTL-SDR dongles that currently supports various features such as a power spectrum plot and frequency scanning. The software can run on a Raspberry Pi 3 and all features are intended to be accessed via an easy to use web browser interface, or via an Android app. The software can also be run with Docker, making it useful for IoT applications.

RTLion project can be described as a framework due to the implementation of various features other than the frequency scanner. The common structure of the project is appropriate for adding new features too. RTLion Framework has a Flask–SocketIO based Web interface which houses it’s features there. Web interface preferred to the command line interface for facilitating the usage and supporting remote operations. Matplotlib used for creating graphs, more specifically pylabpsd(Power Spectral Density) method mostly used for converting the complex samples (stored in a numpy array) to FFT graphs.

Main purpose of the RTLion Framework is creating a framework for RTL2832 based DVB-T receivers and supporting various features such as spectral density visualizing and frequency scanning remotely. These features are provided on the Web interface and accessible via the RTLion server or the RTLion Android App for RTL-SDR & IoT applications.

All of his code is open source and available on Github. Currently he’s looking for feedback on improving the framework and we are interested to see where this project may lead in the future.

Over on YouTube the Radio Society of Great Britain (RSGB) has uploaded a talk by Noel Matthews (G8GTZ) titled "The Farnham WebSDR: DC to Microwaves on your smartphone". The Farnham WebSDR runs 8 (soon to be 10) RTL-SDR dongles in order to cover multiple bands from DC to 2 GHz.

If you're interested in their talks, the RSGB also recently uploaded several other amateur radio related talks from their 2018 convention to their YouTube channel.

This presentation gives an overview of the Farnham WebSDR (http://farnham-sdr.com/) which currently covers the LF bands through to 10GHz. The presentation describes the system architecture and antennas currently used on each band and how the team has used RTL dongle receivers, available for under £10, to give good RF performance on all bands from DC to 10GHz. There is a demonstration of the SDR in use on both PC and smartphone.