Earlier this year the Ukrainian company RigExpert released the FobosSDR, and only recently has it become available to most people in the world via global resellers. FobosSDR is an RX-only USB 3.0 device, with a 100 kHz to 6 GHz tuning range, 50 MHz of bandwidth, and 14-bit ADC resolution. Current pricing from US resellers is US$395 and from EU resellers around 495,00 €.
Recently Matt from the TechMinds YouTube channel reviewed the FobosSDR, showing an unboxing, description and review of the hardware. Unfortunately, while the specs on paper look good, Matt notes that the FobosSDR does not perform well.
In the video, Matt starts by testing around the broadcast FM band and shows how the FobosSDR suffers from multiple mirrored signals, even with the gain settings turned right down. He notes that other similarly priced SDRs perform a lot better and that even an RTL-SDR performs better.
Matt then goes on to test the HF bands, noting that there is no gain control available on these bands and that there are also extreme levels of signal mirroring all across the HF band.
Unfortunately, we are starting to see other similar reports about poor performance from the FobosSDR. For example, on arcticdx's blog he also does not recommend the SDR [1][2],
Over on YouTube the Linus Tech Tips channel has recently released a video about the HackRF titled "It’s TOO Easy to Accidentally Do Illegal Stuff with This". Linus Tech Tips is an extremely popular computer technology YouTube channel. The HackRF is a popular transmit capable software defined radio that was released about 10 years ago. The portapack is an add-on for the HackRF that allows the HackRF to be used as a handheld device, and when combined with the Mayhem firmware, it enables easy access to some controversial tools that could get a user into a lot of legal trouble very fast.
In the video Linus, whose team is based in Canada, mentions that they decided to purchase the HackRF and similar devices because of the Canadian government's plan to ban various RF tools, including the Flipper Zero and HackRF.
Linus then discusses and demonstrates "van eck phreaking" with TempestSDR, showing how he can use the HackRF to recover the video from a PC monitor wirelessly. He then goes on to demonstrate how the Portapack can be used to jam a wireless GoPro camera transmitting over WiFi.
Finally, Linus discusses the legality and morality of such devices being available on the market.
Thank you to Jacopo (@lego11/IU1QPT) and Robin (@OK2AWO) for writing in and sharing with us his thoughts about how the SDR community as a whole should move on from the use of WXtoIMG, and instead switch to SatDump, which now has full feature parity with WXtoIMG and additional features too. SatDump is available on Windows, MacOS, Linux, and even on Android. An up-to-date guide for receiving APT with SatDump written by @lego11 can be found on his website here.
Historically, WXtoIMG has been the software of choice for the popular hobby of decoding NOAA APT weather satellite images with RTL-SDR and other SDRs. However, the software has unfortunately been abandoned by its authors for several years, and can now only be found on third-party websites which increases the possibility of downloading a virus. Also, a hack involving a proxy, or directly updating via a powershell script is now required to allow WXtoIMG to update its TLE/ Kepler files due to the celestrak.com to celestrak.org domain name change.
Lego11 also notes a whole host of other issues regarding vulnerabilities and bugs with WXtoIMG:
The software is ancient and uses obsolete libraries, such as Visual C++ 2002 with .NET. These libraries are the main concern when it comes to WXtoIMG, as I don't find it particularly likely for someone to find an entry point through the software itself. However, a much more likely scenario is a virus abusing the loaded library in memory when WXtoIMG is running and using it to gain an entry point. There are at least 20 vulnerabilities affecting MSVCR70.dll, and all are well known (such as CVE-2007-0025) which makes it even more concerning. CVE-2008-4255 in particular allows for remote code execution on the user's computer, which is very serious. There are certainly many more vulnerabilities that have been exploited regarding MSVCR70, but due to the obsolescence of this software component they are usually not tracked in a CVE.
In either case, just as nobody would use Windows XP as a daily driver in 2024, nobody should use WXtoIMG as a matter of caution, even if the above mentioned vulnerabilities were not present.
As for the bugs, there are many. Here's a list of the most important ones:
Cannot update TLE without external software, complicating the experience for newcomers and adding extra failure points
Map overlay doesn't work properly most of the times, especially if the user starts to receive the satellite before it is at least at 1° elevation
WXtoIMG will crash if Microsoft Defender starts a memory scan during a pass. This will lose the recording
WXtoIMG uses an outdated Win32 API to access audio. This doesn't always work on Windows 11 and Microsoft has stated that it will be removed soon.
WXtoIMG uses ALSA on Linux. The vast majority of Linux distributions don't support ALSA directly anymore, and WXtoIMG cannot work through an audio server (e.g. Pulseaudio) like all Linux applications are supposed to. Therefore, live recording doesn't work on Linux at all.
WXtoIMG doesn't run on MacOS anymore, as the system will refuse execution due to security problems and missing libraries.
WXtoIMG cannot support wav files from e.g. SDR# or SDR++ without using a third party tool such as NOAA-APT.
If a user moves or copies a recorded WAV file (see above), the map overlay will no longer work.
WXtoIMG is especially sensitive to concurrent CPU usage, which will result in "tears" on the image (as is evident on the images in the guy's tutorial). It cannot handle multitasking well on systems more modern than Windows XP due to changes in how the CPU scheduler works in more modern kernels.
WXtoIMG will lock up and then crash if the user starts it without first having updated TLEs due to missing NOAA-17. This is very serious, as it happens to newcomers all the time. It is one of the top support request emails/messages I receive. It is not possible to fix this crash easily.
WXtoIMG doesn't have updated coefficients for calibration, therefore NOAA-15 will look excessively cold compared to other satellites.
Thank you to RTL-SDR.COM reader Micha for submitting a story about how he has been able to use SDR# and the Airspy Server Network to explore cable TV stations across the globe via cable TV signal interference.
If you were unaware, the SDR# software from Airspy.com has access to the Airspy Server Network, which is a collection of public Airspy SDRs available all over the world that can be accessed freely over the internet. To access these SDRs simply select "Airspy Server Network" as the source in SDR#, and click on the "..." button next to the server address entry. A map will pop up where you can select from SDRs all over the world.
Using Airspy SDRs in Russia, and in other countries (Guatemala, Brazil, Chile, Uruguay, Mexico, Dominican Republic, Argentina, Indonesia, Vietnam, Micha found that there were several analog TV signals found at frequencies that should not have terrestrial TV signals there. Upon further investigation, he realized that these are actually cable TV signals that are leaking and causing interference across the RF bands. Micha notes that he's also observed how the leaking signals often change in frequency and intensity too, making it difficult to keep track of them.
Combined with the TVSharp SDR# plugin, Micha was able to recover some (very rough) images from these interfering signals. Micha has provided several images shown below that demonstrate Russian cable leakage, as well as for Mexico and Argentina.
Over on YouTube Baltic Lab has uploaded a video showing how he was able to successfully use an RTL-SDR Blog V4 and the included multipurpose dipole antenna kit to receive images from polar-orbiting NOAA weather satellites.
In the video, Baltic Lab shows how to orient the dipole antenna in a "V-Dipole" shape which optimizes it for receiving from satellites. He also shows how to use a VNA to confirm that the telescopic elements on the dipole are extended to the correct length, noting that he was able to achieve a VSWR of less than 1.2 between the target frequencies of 135 to 138.1 MHz, with a near perfect match at 136.5 MHz.
He then demonstrates receiving the NOAA APT signals with his laptop, and successfully recovering the weather satellite image.
Over on the YouTube channel "SecPGH" a talk by Grey Fox titled "Introduction to Software Defined Radio For Offensive and Defensive Operations" has been uploaded from the BSidesPGH 2024 conference. BSidesPGH 2024 was a security conference held in Pittsburgh, PA, USA on July 25.
The talks are generally about network security, however, Fox's talk is all about RF security topics and software defined radio. In the talk, he introduces SDR, and devices like the Flipper Zero and demonstrates various basic examples such as receiving FM from a handheld radio and ADS-B.
Next, he goes on to demonstrate security topics such as showing how to capture and analyze signals from a 433 MHz security alarm using an RTL-SDR and Flipper Zero, and how to jam frequencies and replay captured signals. Finally, he demonstrates WiFi cracking with the help of Kali Linux and Flipper Zero with WiFi dev board attached.
Over on YouTube "Sam's eXperiments logs" have uploaded a video showing how he was able to succeed when using TEMPESTSDR to eavesdrop on HDMI cables with his SDRplay. TEMPESTSDR software combined with a software defined radio allows a user to eavesdrop on TVs, monitors, and more by wirelessly receiving their unintentional RF emissions and recovering information from those emissions. In many cases it is possible to recover live images of the display, clear enough to read text.
Sam's video explains the challenges he faced with signal strength due to the highly effective shielding of his HDMI cables. To get around this Sam shows how he unshielded his HDMI cables for the test. This is good news for privacy, as it shows how effective shielding can be at stopping these kinds of attacks. He then goes on to show the results he obtained which show text being read from his screen.
Over on the Tech Minds YouTube channel, Matt has uploaded a video where he reviews a new book by Elektor titled "Raspberry Pi 5 For Radio Amateurs" (€5 off coupon code "Techminds"). The book is all about projects for the Raspberry Pi 5 that can be done with RTL-SDR Blog V3 and V4 software defined radios.
In the video Matt explores the books contents, showing off the various possible projects. Matt also shows how to get started with the book by installing Raspbian, and the RTL-SDR drivers, and then goes on to show how examples of the various software programs mentioned in the book such as SDR++, flrig, chirp, dump1090, predict, HamClock, rtl_tcp, rtl_433, qsstv, fldigi, Xdx and more.
Back in April of this year, we posted about the FobosSDR, an upcoming software defined radio product from the Ukrainian company RigExpert. FobosSDR is an RX-only USB 3.0 device, with a 100 kHz to 6 GHz tuning range, 50 MHz of bandwidth, and 14-bit ADC resolution. At the time of the previous post, FobosSDR was not yet for sale, but now we see that it is available from some European distributors with a price of 495,00 € (~US$544).
Recently 'Radio Bunker' has uploaded a video review of the FobosSDR on his YouTube channel. Note that the video is in Spanish, however, you can use the YouTube auto-translate function.
In the video, Radio Bunker unboxes the FobosSDR and explains its specs and features, then goes on to show how to install the drivers and get it up and running with SDR#. He then shows the SDR receiving some signals like broadcast AM, FM, shortwave, DAB, and WiFi in SDR# with 50 MHz bandwidth.
Over on YouTube The Comms Channel has uploaded a video showing how they used a KrakenSDR to track down the location of an ATIS transmission tower.
If you weren't already aware, KrakenSDR is our 5-channel coherent radio based on RTL-SDRs, and it can be used for applications like radio direction finding. It can be purchased on Crowd Supply.
Airports typically have an ATIS (Automatic Terminal Information Service) transmission tower that broadcasts audio of recorded information such as weather, runway conditions, and any important notices.
In the video, they use the KrakenSDR to track down the location of an ATIS transmission tower at their local airport. In the future, they intend on using the KrakenSDR to help track down Meshtastic radios.
Over on hackster.io we've seen a story about how maker Jon Dawson designed a self-contained software-defined radio based on the Raspberry Pi Pico that can receive 0 - 30 MHz, with up to 250 kHz of bandwidth. The Raspberry Pi Pico is a microcontroller board based on the Raspberry Pi Foundation's own RP2040 chip.
The Pi Pico Rx's front end consists of a Tayloe Quadrature Sampling Detector (QSD) mixer which makes use of the PIO (Programmable Input/Output) feature on the RP2040. The circuit also has an encoder knob for tuning and a small OLED screen.
Jon had originally created the Pi Pico Rx on a custom PCB, however, his latest work brings the cost down by showing that it can just as easily be implemented on a breadboard with through-hole components.
The full writeup can be found on Jon's blog "101 Things", as can the open source firmware. He has also uploaded a YouTube video explaining and demonstrating the project which we've embedded below.
The LibreSDR is a relatively new software defined radio on the market. It is based on the AD9363 radio transceiver chip and an AMD XC7Z020 FPGA, and appears to be an upgraded/modified Chinese clone of the PlutoSDR. It can be found on marketplace sites like Banggood for US$319.99. (The Tech Minds YouTube description box also notes coupon code BG91c241, Exp:8/31, which brings it down to US$$259.99)
In his video, Matt from the Tech Minds YouTube channel introduces the LibreSDR / ZynqSDR, and explains how to set up the LibreSDR firmware, which is an unofficial port of the PlutoSDR firmware.
He then tested the SDR with SDR++ on Windows for receiving the air-band and found that it worked well, except that it only worked over USB, and did not work with the ethernet connection. Next, he tries SDR-Console V3, and finds that he is able to connect to the LibreSDR via ethernet with this software. Matt goes on to test his QO-100 setup, replacing his PlutoSDR with the LibreSDR, noting that the VCTXO in the LibreSDR works great to prevent any signal drift.
Finally, Matt tests transmission of DATV with the LibreSDR, but finds an issue with a center spike causing issues with decoding. He notes that the center spike does not occur with his PlutoSDR.
The latest August edition of the RadioWorld Magazine has included an article by James Careless about the use of software defined radios for shortwave radio listening. RadioWorld is a magazine targeted towards radio broadcast owners, managers and engineers all over the world. The article explores SDRplay and RTL-SDR Blog V4 units from the perspective of a shortwave listener new to software defined radios, comparing them to his high-end Sangean ATS-909X2 shortwave digital receiver.
Over on her YouTube channel SignalsEverywhere, Sarah has uploaded a new video showing how to use a program called 'hacktv-gui' to transmit analog TV signals using a HackRF software defined radio. Analog TV standards such as PAL and NTSC have been phased out in most of the world in favor of digital TV standards instead. However, transmitting these yourself can be a fun experiment that may help breathe life into old television sets.
In the video Sarah explains how to use the hacktv-gui and hacktv software, and how to create a video transmission. She mentions how hacktv also supports the use of a FL2K device, which is a cheap VGA adapter that can be used to transmit signals.
The RTL-SDR hardware began its life as a DVB-T TV receiver USB stick, but these days it is rarely used for this purpose. However, in countries where DVB-T hasn't been upgraded to DVB-T2 it is still possible to use the RTL-SDR for TV reception.
Recently, RADIOTO bg from DXing.org wrote in and wanted to share with us his video showing how to use the RTL-SDR V3 for DVB-T reception in OpenPli Enigma2. OpenPli is an open-source Linux distribution for TV set-top boxes and Enigma2 is the TV application it runs.
RADIOTO's video shows a step-by-step guide to setting up the RTL-SDR in OpenPli. The procedure is relatively simple, just requiring the user to select the correct driver for the RTL-SDR via the set-top menu.
Recently on the Tech Minds YouTube channel, Matt uploaded a video explaining how to set up and use the Radioberry HF SDR Transceiver Pi Hat. The Radioberry is an HF SDR transceiver based on the AD9866 chip. It has an operating frequency between 0 - 30 MHz, a 12-bit ADC, a maximum bandwidth of up to 384 kHz, and one RX and one TX channel. It is designed as a 'Pi hat' which means that it needs to be connected and sit on top of a Raspberry Pi single-board computer.
In his video Matt shows how to set up the Radioberry Raspberry Pi software. The process begins with installing the Raspbian OS, logging into SSH, and running the Radioberry installation script. He then shows how to connect to the Radioberry over a local network using SDR-Console V3. Later he shows how to install the pihpsdr software which gives the Radioberry a desktop control app that can be used with a LCD screen connected to the Raspberry Pi.
Matt goes on to show how he was also able to use the Radioberry TX function to make WSPR contacts across Europe from with his home location in the UK, despite its very low 150 mW output power.
Over on his YouTube channel, Simon has uploaded a video showing how while on holiday he was able to explore the various HD Radio stations available around the USA.
If you are in the USA, you might recognize HD Radio (aka NRSC-5) signals as the rectangular looking bars on the frequency spectrum that surround common broadcast FM radio signals. These signals only exist in the USA and they carry digital audio data which can be received by special HD Radio receivers. Earlier in 2017 a breakthrough in HD Radio decoding for SDRs like the RTL-SDR was achieved by Theori when he was able to piece together a full HD Radio software audio decoder that works in real-time. Nowadays you can use software like HDFM - HD Radio GUI to easily receive HD Radio with an RTL-SDR.
In his video Simon shows the various HD Radio signals he found while on holiday, and also shows some of their secondary features, including traffic data, and weather radar maps. Interestingly he also spots HD Radio in the AM bands, but finds his signal is not strong enough to decode.
The rest of the video explores other signals he finds such as a studio link, and TV audio signals.
This post is about the KrakenSDR, one of our products from our sister company KrakenRF. If you weren't already aware, KrakenSDR is our 5-channel coherent radio based on RTL-SDRs, and it can be used for applications like radio direction finding. It can be purchased on Crowd Supply.
In this update we'd like to share some of the KrakenSDR projects we've been working on, as well as various projects we've seen from our customers.
Kraken Pro Cloud Online Mapper Updates
Recently we've been working hard at improving the 'Kraken Pro Cloud' online mapper service at map.krakenrf.com. If you were unaware, this service is an online mapping application that can be used together with one or more KrakenSDRs to display their generated bearings on a map. This is useful if you have multiple KrakenSDRs at fixed sites spread out over a wide area, as it allows you to instantly triangulate. The features include:
Multiple Kraken's displaying on a single map
Display a Heatmap just like the Android App
Ability to remote control the Kraken's individually, or all together from a single interface
Ability to share your Kraken with other users
Display log files collected from the Android App or Kraken Web GUI
Recently we've added multiple new features and improved several points:
Ability to plot multi-VFO (multi frequency) data coming from a KrakenSDR
Ability to put Kraken's into groups
Improved heatmap calculation and rendering speed
Fixed a memory leak that caused the mapper to crash after several hours
Improved the history feature (see further below)
Improved the interface
We'd like to especially highlight the improvements to the history feature. The history feature allows you to look back in time and see what the bearings and heatmap at that time looked like. This is useful if you are tracking something, but don't know exactly when the transmissions occur, or are tracking a moving object, and want to be able to review data at a later time.
Currently, we are supporting up to a week of free history, but this may change depending on how much history affects server load. For full disclosure, we eventually plan on making longer history recording available, but this will likely be a paid subscription feature. The timeframe of free history provided may change in the future too.
We also added the ability to play back history at faster speeds, kind of like a timelapse. To do this the heatmaps for each interval need to be precomputed first so that the playback is smooth, and so a 'precompute' button has been added.
We also want to note again that Kraken Pro Cloud is currently in beta, and there may still be some bugs. We also do not guarantee any uptime or privacy so please do not use the service for mission critical tasks. If you encounter bugs, please report them on our forums at https://forum.krakenrf.com, or via email to thekraken@krakenrf.com.
The gif animation below shows heatmap playback at 4x speed while the KrakenSDR was tracking the bearing towards a weather balloon.
Kraken Pro Cloud Mapper History Playback
KrakenSDR Core Updates
Since the last update we have made various bug fixes and a few minor changes to the core software. We highlight some changes below:
Our images have been updated to include SignalMedic's TAK server. (More on this in a section below)
(Beta feature) Added the ability to demodulate narrowband FM to audio files. This is in beta as the audio files don't come out particularly clean sounding, but it may be useful for some.
With the release of the Raspberry Pi 5, we have now also added a Raspberry Pi 5 ready-to-use image as well. The Raspberry Pi 5 runs the KrakenSDR software very smoothly and makes the GUI very responsive. Performance is similar to the Orange Pi 5. If are are new and choosing a platform to run the KrakenSDR on, we would highly recommend the Raspberry Pi 5 now.
Recently we have been working on getting an iOS version of the KrakenSDR app out. The app is close to completing development and should be out within about a month. Once released we will update our Wiki with links to the app, or you can simply search on the iOS app store for 'KrakenSDR'
KrakenSDR Crowdsupply Conference Workshop
One of the members of our team, Syed, recently ran a workshop on KrakenSDR. The workshop had attendees put together a KrakenSDR set on a large pizza pan and had teams go out into a local park to find a hand held radio transmitter. Photos of the day can be found here.
KrakenSDR Workshop at the Crowd Supply Conference
Highlights from Customers
KrakenSDR YouTube Tutorial from Skyler F
Over on YouTube user 'Skyler F' has uploaded a great video that demonstrates and shows how to set up KrakenSDR. In the video he demonstrates him finding some cellular phone towers.
KrakenSDR Talk by KO4CEQ
We've also seen a great talk by KO4CEQ about KrakenSDR which has been uploaded to YouTube. In the talk he discusses KrakenSDR and shows his very neat car based setup.
Elektor Review of the KrakenSDR
Online store and magazine Elektor has uploaded to their blog a great review of the KrakenSDR. In the review they explain the KrakenSDR specs, and how it can be used as a regular SDR, and then go out to show how they created an antenna array and used the DoA software.
Elektor's Review of the KrakenSDR
Signal Medi's TAK Server
Thanks to 'SignalMedic' who had coded up a TAK server for KrakenSDR. TAK (Tactical Assault Kit) is software used by the military and other organizations for visualizing geospatial information such as enemy and friendly positions. Civilian versions of TAK also exist, such as ATAK for Android.
The TAK server allows for a KrakenSDR cursor to appear on a TAK map. TAK only allows for a single bearing line to show, so it's not as effective as our own mapping app, but this may be useful for customers who are only using TAK.
SignalMedic has made two implementations. One based on NodeRED, and the other based on Python. As mentioned previously, our image files now include the Python TAK server.
KrakenSDR TAK Server by SignalMedic
Aaron (aka cemaxcuter, aka creator of DragonOS) has also uploaded a video showing the TAK server in action.
Adrian's 3D Printed Antenna Spacer Arm
In the past we've highlighted Adrian's excellent 3D printed antenna spacer. The files for the 3D printed antenna spacer are available on Thingiverse.
Adrian has recently created a modified version of the arm that is significantly longer and should be able to cover 150 MHz to 1766 MHz. He also notes that he's updated the original arm to include files for laser cutting.
Dbvanhorn 3D Printed Antenna Spacer
We've also seen another 3D printed antenna spacer uploaded to Thingiverse. This file is based on OpenSCAD and allows you to customize the length to be printed.
Over the years we've posted several times about the TEMPEST applications of software-defined radio. TEMPEST aka (Van Eck Phreaking) is when you listen to the unintentional RF emissions of electronics and are able to recover information from that. In the past, we posted about TempestSDR, an RTL-SDR compatible program that allows you to view images from a computer monitor or TV simply by picking up the unintentional RF emissions from it.
Usually, the images received are fuzzy and it can be difficult to recover any information from them. However recently there has been work on combining Tempest techniques with deep learning AI for improving image quality.
Deep-tempest has recently been released on GitHub and from their demonstrations, the ability to recover the true image with deep learning is very impressive. From a fuzzy grey screen, they show how they were able to recover clear text which looks almost exactly like the original monitor image.
Deep-tempest is based on gr-tempest, and requires GNU Radio, Python 3.10 and a Conda environment. Instructions for installing it are on the GitHub.
The whitepaper on the University research done to implement Deep-Tempest can be found freely on arxiv at https://arxiv.org/pdf/2407.09717.
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