A couple of days ago we ran a post noting that the Airspy HF+ WRTH review was now available for public viewing. Now thanks to Jon Hudson of SDRplay for letting us know that the SDRplay RSPDuo review from WRTH has also been released for public viewing (pdf). The SDRplay RSP Duo is a 14-bit dual tuner software defined radio that is capable of tuning between 1 kHz - 2 GHz, with two separate 2 MHz bandwidths tuned to anywhere within that frequency range.

The review provides an overview of the RSPduo noting it's various features and discussing the SDRuno software. They also note that diversity reception would be an excellent application for a dual tuner SDR, but SDRuno does not support this feature as of yet. In their tests they also mention how they found very few overloading problems.

Jon would also like to note that the pricing in the review is incorrect. The RSPduo is US$279.95, and right now there is a seasonal $50 discount for US customers at HRO.

Over on YouTube channel Tech Minds has uploaded a video that shows how to install and use RPiTX version 2. RPiTX is software for the Raspberry Pi which can turn it into a 5 kHz to 1500 MHz transmitter which can transmit any arbitrary signal. RPiTX requires no additional hardware, but a filter is required for transmitting with any power or gain. Back in November RPiTX was updated to version 2 which brought with it a new GUI, and improved spectral purity.

In his video Tech Minds goes over the installation of RPiTX, and then goes on to demonstrate it in action with an RTL-SDR and SDRUno used as the receiver. He shows the several TX modes available such as the tone/chirp generator, spectrum painter FM with RDS, SSB and FreeDV.

SatNOGS is an open source project that aims to make it easy for volunteers to build and run RTL-SDR or other SDR based RF ground stations that automatically monitor satellites, and upload that data to the internet for public access. The antennas used in a typical home based SatNOGS station are small enough for a single person to handle, however recently the SatNOGS team have been working on setting up a monitoring station at the Dwingeloo Radio Observatory in the Netherlands.

Dwingeloo has a large 25 meter satellite dish antenna, and they connect it to an RTL-SDR on a laptop running the SatNOGS software. In the video they show it tracking the PRISM amateur radio satellite, and note that the use of this large dish will only be used in special circumstances. They write:

This week the Dwingelooradio Observatory tested their 25 meter dish as a SatNOGS station! Although not set up as a permanent SatNOGS station it is great to see this historic observatory linked to the network. Dwingeloo radio observatory was built between 1954 and 1956 near the village of Dwingeloo in the Netherlands. Since 2009 this single 25 meter dish has been a national heritage site.

Thank you to Giuseppe (IT9YBG) who just wanted to write in and note that Android TV boxes are an excellent computing platform for RTL-SDR dongles. They allow you to monitor frequencies or listen to DAB music directly from a TV, and at the same time there is no need to worry about battery consumption.

Giuseppe notes that using an Android TV box for SDR is as simple as installing the Martin Marinov Android RTL-SDR drivers from the Google Play store, and then downloading the SDR apps that interest you. No extra USB OTG cable is required, just plug the dongle into the back of the device. In his post he shows screenshots from apps like SDRTouch, welle.io DAB+, RTL-SDR AIS and SDRoid all running smoothly on his Android TV box.

With a system like this is it probably also a good idea to connect a wireless keyboard/mouse combination into a USB port as well.

Over on GitHub, Rakesh Peter (r4d10n) has uploaded a new terminal/ssh based console application called "retrogram~rtlsdr". This program uses an RTL-SDR and terminal window to display a spectrum analyzer drawn in ASCII art. Because it is terminal based, it is even possible to view the spectrum of a remote device over an SSH connection. The program is based on software designed for Ettus USRP SDRs, and has been adapted for RTL-SDR.

For other SDRs r4d10n has also worked on a "retrogram~soapysdr" version which should work with any SoapySDR compatible SDR, and "retrogram~plutosdr" for PlutoSDR SDRs.

Over on YouTube user ModernHam has uploaded a video showing how to perform a replay attack on a car key fob using a Raspberry Pi running RPiTX and an RTL-SDR. A replay attack consists of recording an RF signal, and then simply replaying it again with a transmit capable radio. RPiTX is a program that can turn a Raspberry Pi into a general purpose RF transmitter without the need for any additional hardware.

The process is to record a raw IQ file with the RTL-SDR, and then use RPiTX V2's "sendiq" command to transmit the exact same signal again whenever you want. With this set up he's able to unlock his 2006 Toyota Camry at will with RPiTX.

We note that this sort of simple replay attack will only work on older model cars that do not use rolling code security. Rolling code security works by enduring that an unlock transmission can only be utilized once, rendering replays ineffective. However, modern rolling code security systems are still susceptible to 'rolljam' style attacks.

In the video below ModernHam goes through the process from the beginning, showing how to install the RTL-SDR drivers and RPiTX. Near the end of the video he shows the replay attack in action.

Over on YouTube user knoxieman has uploaded a video that provides a few tips on using DSD+ and an RTL-SDR for listening to DMR digital voice signals. The video is designed as a companion to Tech Minds' video which shows a full set up procedure for DSD+.

Knoxieman's video includes some tips on SDR# settings, virtual audio cable setup, and using a program called "DisplayFusion" to keep the DSD+ event windows permanently on top of the SDR# window. 

On December 16 Rocket Lab launched 13 new cubesats into orbit via it's Electron rocket which was launched from New Zealand. One of those Cubesats is "CubeSail" which is a set of two satellites that aims to deploy a 260 m long solar sail between the two.

CubeSail is a technology demonstration by CU Aerospace which shows the viability of solar sail propulsion for deep space missions. It was built and is operated by students at the University of Illinois at Urbana-Champaign through the Satellite Development, or SatDev student organization.

Over on Reddit, one of the engineers working on the Cubesail project has put out a request to help receive and upload any telemetry that you receive from the Cubesail satellite. Currently they only have one ground station which makes monitoring the satellite difficult as they can only collect data when it is passing overhead.  By employing the help of radio enthusiasts from around the world they hope to gather more data. He writes:

According to the information a 437 MHz antenna is required, and most likely it will need to be a directional antenna that is hand or motor tracked. Some SatNOGS ground stations are already receiving and recording Cubesail data too.

Back in early 2017 we posted about Manuel's (aka DO5TY / Tysonpower) design for a single band 140 MHz 3D printed carbon fibre Yagi antenna. Today he's submitted a new video about creating a dual band 3D printed carbon fibre cross Yagi antenna for only 20€. Note that the video is narrated in German, but there are English subtitles. He's also uploaded an English text tutorial to his blog, which includes links to the 3D printer STL files.

The antenna is designed to be a low cost replacement for the commonly used Arrow dual band 2m/70cm antenna which is designed for receiving and transmitting to amateur radio satellites. Many amateur radio satellites have an uplink frequency set at around 145 MHz, and a downlink frequency around 435 MHz (and some satellites have the frequencies reversed). So a dual band Yagi is ideal for these satellites. Manuel writes that with his 5W Baofeng handheld he's already made several successful contacts with his new antenna.

Manuel's antenna consists of several 3D printed joints, with a carbon fibre rod used as the main boom. Aluminum rods make up the receiving and transmitting elements. The video also discusses impedance matching and how he uses a diplexor so that there is only one connection required to the radio. The advantage of his antenna over the Arrow is that it is significantly cheaper, and also much lighter in weight.

Over on YouTube SignalsEverywhere (aka Corrosive) has uploaded a new video where he shows a demonstration of him listening in to a DECT digital cordless phone with his HackRF. 

DECT is an acronym for 'Digital Enhanced Cordless Telecommunications', and is the wireless standard used by modern digital cordless phones as well as some digital baby monitors. In most countries DECT communications take place at 1880 - 1900 MHz, and in the USA at 1920 - 1930 MHz. Some modern cordless phones now use encryption on their DECT signal, but many older models do not, and most baby monitors do not either. However, DECT encryption is known to be weak, and can be broken with some effort.

In his video Corrosive uses gr-dect2, a GNU Radio based program that can decode unencrypted DECT signals. In the video he shows it decoding a DECT call from his cordless phone in real time.

Bitcoin is a digital currency based on blockchain technology, and Blockstream are a large innovator in the Bitcoin world. They have recently been developing the 'lightning network' which is a layer that sits on top of the blockchain. The goal of the lightning network is to provide a second layer that helps to speed up bitcoin transactions and alleviate network congestion.

In a previous post we noted that Blockstream have data channels leased on several geostationary satellites. The goal of these satellites is to help users download the blockchain, which is the ledger of all bitcoin transactions ever made. Over time the ledger grows and becomes larger and larger, and at the time of writing is currently about 200 GB in size. Rural/field users of Bitcoin with slow, intermittent, or no internet connection can use this satellite to download or update their ledger and confirm that they have received payments.

To receive the satellite an RTL-SDR dongle together with a Linux PC, LNB and satellite dish antenna are used. More information about setting up a receiver can be found on their GitHub.

Recently Blockstream have released news that their satellites now support Lightning transactions. In addition the Asia-Pacific satellite is now online. This should help boost adoption of the lightning network among rural users.

Thank you to YouTube user "ModernHam" for submitting his video that shows one way to weatherproof our 'RTL-SDR Blog Multipurpose Dipole Antenna'. This is the antenna we include as part of our RTL-SDR kit, and it is an excellent beginners antenna. Dipole antennas typically receive better than mag-whips, are easier to mount on windows, and can receive 137 MHz weather satellites too.

However, due to their portable telescopic collapsible design, our antennas are not designed for permanent outdoor use as dirt and grime can gum up the collapsing mechanism. In his video ModernHam decided to waterproof the dipole for permanent outdoor mounting. To do this he modified the plastic base by cutting it down, and then places the dipole inside a PVC pipe with some bubblewrap used to hold it in place. This keeps the elements out, and looks pretty good mounted up high too.

Thanks to Zoltan (aka Veryokay on YouTube) for submitting information about his Inmarsat STD-C EGC live stream setup. His setup allows him to access the Inmarsat STD-C signal from anywhere in the world over the internet, thanks to the use of an OpenWebRX server. Inmarsat STD-C is a geostationary satellite service that provides information for search and rescue, as well as news, weather and incident reports for mariners. We have a tutorial from a few years ago which shows some example messages. OpenWebRX is an efficient SDR streaming server platform that allows you to access RTL-SDR's and other SDRs from anywhere in the world via an internet connection.

In his setup Zoltan uses a Raspberry Pi 3, RTL-SDR Blog V3, L-band LNA and L-band antenna for receiving and processing the signal. Power is provided via a Power over Ethernet (PoE) adapter, and the whole thing is placed outside, in a weatherproof plastic lunchbox.

The video shows the hardware, and then goes on to describe the software setup, along with a demonstration of the OpenWebRX stream. More information as well as the link to his publicly accessible OpenWebRX Inamrsat STD-C stream can be found on his blog post.

For ADS-B decoding, dump1090 is an RTL-SDR compatible program that is commonly used. In order to provide information about the aircraft being detected (e.g. icao24 hex address, registration/tail number and sometimes the type of aircraft like A380), dump1090 uses an offline database. Unfortunately this database has not been maintained in a very long time, so it is now out of date, and so cannot display information about many aircraft.

Recently Thierry had the idea to use the data from VDL2 aircraft transmissions to update his dump1090 database. VDL2 is a short data messaging system used by aircraft that will eventually replace the older ACARS messaging system. With an RTL-SDR and vdlm2dec decoder, the VDL2 signal which broadcasts at around 136 MHz can be received and decoded.

Contained within the data is the icao24 hex address and registration/tail number. By collecting this VDL2 data over a number of days, a new database can be generated which can then be imported into the dump1090 database. It however, doesn't seem to acquire aircraft type data.

Over on YouTube SignalsEverywhere (aka Corrosive) has uploaded a tutorial video showing how to use TempestSDR with an Airspy SDR. Back in November 2017 we posted about how we were able to get TempestSDR to run with an RTL-SDR, Airspy and SDRplay, and showed some results. Since then several people have managed to repeat our results, but many have also had trouble understanding how to make TempestSDR work and what all the settings are for.

TempestSDR is an open source tool that allows you to use any SDR that has a supporting ExtIO (such as RTL-SDR, Airspy, SDRplay, HackRF) to receive the unintentional signal radiation from a screen, and turn that signal back into a live image. This can let you view what is on a screen without any physical connections.

Corrosive's tutorial video shows us how to tune the signal in the TempestSDR software in order to receive a clear image as well as showing the software in action.

Welle.io is a Windows/Linux/MacOS/Android/Raspberry Pi compatible DAB and DAB+ broadcast radio decoder which supports RTL-SDR dongles, as well as the Airspy and any dongle supported by SoapySDR. It is a touch screen friendly software which is excellent for use on tablets, phones and perhaps on vehicle radio touch screens.

Thank you to Albrecht Lohofener, the author of welle.io for writing in and sharing his news about the release on welle.io version 2.

welle.io 2.0 Beta 1 released

I’m happy to announce the version welle.io 2.0 Beta 1. Since the first rtl-sdr.com post roughly two years ago (Mar 2017) welle.io became the leading open source DAB/DAB+ SDR. Many people are using welle.io in their daily life and gave a lot of feedback.

With all this feedback we started developing the version 2.0. Apparently, the biggest change is the complete redesign of the user interface (GUI). It changed from a dark design to a bright design and handles easily different screen resolutions and orientations.

Many users asked for a favorite list, automatic playing of last station and a mute button. Now these features are ready to test with the 2.0 Beta 1!

Another new feature is the settings menu where users can set the hardware receiver with all the necessary settings. This is more user friendly than the command line parameters.

For people with a deep technical interest we improved the expert mode a lot. In addition to the spectrum users can also view the impulse response, null symbol and constellation diagram, even at the same time! An experimental I/Q RAW file recorder as well as a debug output window is available for systems without a text console.

In the back-end we improved the multi-path behavior and started a source code refactoring to allow the code to be easily maintained. Great thanks to the people from the Opendigitalradio association (http://www.opendigitalradio.org/) which are actively contributing to this project.

Now it is possible to build a complete DAB/DAB+ system (transmitter and receiver) with open source!

As a result from this collaboration welle-cli is available. The main use case is to monitor DAB/DAB+ transmitters networks over the internet. Thus it has a HTTP API and includes a basic Web page which shows the features.

Everyone is invited to test the new version and to report issues. For reports we recommend to open an issue at the welle.io Github page (https://github.com/AlbrechtL/welle.io/issues).

We are also looking for people who would like to contribute to welle.io (translations, web page, documentation and development).

Download link: https://github.com/AlbrechtL/welle.io/releases/tag/v2.0-beta1

We wish everyone a happy New Year!

Outernet's moRFeus is a signal generator and frequency mixer that can be controlled either by it's built in LCD screen, or via software on a Windows or Linux PC. It can generate a clean low phase noise tone anywhere between 85 to 5400 MHz. Because it can be computer controlled it is possible to use moRFeus as a tracking generator for characterizing filters and measuring antenna SWR. A tracking generator is just a signal generator that can be set to output at the same frequency that the measurement receiver is tuned to.

In the past we've posted about some software developed by Ohan Smit, which allows a moRFeus to be controlled on a Windows/Linux PC via a nice GUI. Recently he's updated the software and it can now draw power (dbFS) graphs for characterizing filters when combined with an Airspy and TCP comms to GQRX. Ohan writes:

So when you press sweep, it detects if there is any TCP servers on port 7356 and if so tunes the radio and gets a power measurement and after the sweep is done, morfeusqt renders a graph on the fly.

It now also supports multiple devices, no configurations required. It just opens another window for the second device.

These features thus far work on both Windows 10 and Ubuntu 18.04.1, these are my two testing environments with GQRX and the Airspy.

Ohan also notes that he's working on several new features such as the ability to plot VSWR, remote control of the moRFeus via TCP, support for multiple SDR TCP protocols such as rtl_tcp, soapytcp etc, threading and progress bars, as well as possibly support for cheap Osmo-FL2K devices as a tracking generator.

You can follow his developments live on the Outernet forums.

The PlutoSDR is an Analog Devices $99 - $149 RX/TX capable SDR with 20 MHz of bandwidth and a 325 MHz to 3.8 GHz frequency range that is software hackable to 56 Mhz of bandwidth and a 70 MHz to 6000 MHz frequency. It has an on board Xilinx Zynq Z-7010 FPGA, which has a built in dual core ARM Cortex-A9 processor as well. This processor is capable of running Linux and Linux SDR software on the PlutoSDR itself. PlutoSDR's can be purchased directly from Analog Devices, or via Arrow, DigiKey or Mouser.

Recently "Lama Bleu" has been working on a custom firmware image for the PlutoSDR. Installing custom firmware allows you to load up a pre-configured Linux system which already has a bunch of useful software installed. He writes that his version is not designed to have a nice GUI, but rather focuses on scripting and data acquisition software. A list of software pre-installed to the image is shown below:

• iio tools : iio-info, libiio 0.16
• CW generator (python) (FG8OJ for CW processing code : https://github.com/fg8oj/cwkeyer)
• SoapySDR + SoapyRemote 0.6 (Pothosware https://github.com/pothosware/SoapySDR)
• LeanTRX ( + DATV TX scripts) (F4DAV and PABR team http://www.pabr.org/radio/leantrx/leantrx.en.html)
• Python 2.7 + numpy ( including iio and SoapySDR bindings)
• rxtools : rx_sdr, rx_fm, rx_power ( Robert X. Seger https://github.com/rxseger/rx_tools
• Retrogram (Peter Rakesh https://github.com/r4d10n/retrogram-plutosdr)
• LUAradio (Vanya Sergeev http://luaradio.io)
• multimon-ng (Elias Önal https://github.com/EliasOenal/multimon-ng/)
• csdr ( + nmux) (Simonyi Károly College for Advanced Studies https://github.com/simonyiszk/csdr)
• OpenWebRX (András Retzler HA7ILM https://sdr.hu)
• gnuplot + libpng ---> signal.sh script to acquire and plot directly on the pluto using rx_power.
• Busybox utilities : netcat, at, timeout, ntpd and more (at and timeout to perform scheduled tasks or end a task).
• morfeus_tool !

To access these tools you simply connect to the PlutoSDR via a network connection and SSH. With some of the tools installed it is possible to do things on board the PlutoSDR like recording signals, demodulating signals, transmitting CW, stream demodulated audio over a network, plot the spectrum on the terminal, create an online SDR with OpenWebRX, do a long spectrum scan and transmit DATV. 

An alternative custom firmware is PlutoWeb which we posted about in the past. This image is designed for creating a web interface GUI, and for running streaming software such as OpenWebRX.

Thank you to Zoltan for submitting his scripts for installing the rtlsdr-wsprd WSPR decoder onto a Raspberry Pi, and showing us how to configure it for an RTL-SDR V3 dongle running in direct sampling mode. This set up allows users to create an extremely low cost and permanent RX WSPR monitor.

WSPR is an amateur radio digital HF mode designed to be decodable even if the signal is transmitted with very low power and is very weak. It can be used to help determine HF radio propagation conditions as WSPR reception reports are typically automatically uploaded to wsprnet. Direct sampling mode on the RTL-SDR V3 allows you to receive HF signals without the need for an upconverter. For best results it is recommended to use a simple bandpass filter for the band of interest.

Zoltan's tutorial comes with a companion YouTube video where he demonstrates his set up. He uses a random wire antenna on his roof directly connected to an RTL-SDR V3, which is connected to a Raspberry Pi 3.  The Pi 3 communicates to his home network via an Ethernet cable.

Over on YouTube Corrosive has uploaded a new tutorial video showing us how we can demodulate DVB-S DATV (Digital Amateur TV) on a Windows PC with SDRAngel. DATV is a mode used by hams to transmit and receive digital video, and SDRAngel is a multiplatform SDR software platform that supports multiple SDRs such as the RTL-SDR, HackRF, PlutoSDR, LimeSDR and more.

SDRAngel comes with a built in DATV demodulator, but it is necessary to install the FFMPEG video decoder yourself. Corrosive's tutorial shows where to download the decoder, and how to install it into SDRAngel. He then goes on to show how to use SDRAngel to begin receiving and demodulating a DATV signal.

We note that in a previous post Corrosive also showed in another video how to transmit and receive DATV with a LimeSDR and a modified $20 DVB-S receiver.