Over on his YouTube channel Tom Stiles (hamrad88) has been experimenting with and reviewing our multipurpose dipole kit. Tom is a ham radio YouTuber who runs a show that produces content often, so we encourage you to subcribe to his channel if you're interested. Tom reviewed our dipole kit over a series of 5 videos which we link here [1: Discussing the product], [2: Unboxing], [3: First ADS-B Tests], [4: Second ADS-B Tests], [5: Third ADS-B Tests]. We post have embedded video 2 and 5 below.
In his testing Tom finds that using the antenna in the vertical orientation improves ADS-B performance. This is expected as ADS-B signals are vertically polarized, and so the antenna should be too. By using the included suction cup mount Tom is able to get the antenna attached to his window which improves reception by getting the antenna as close to the outdoors as possible. This is an expected use case for the antenna, and it's good to see that good results are being had!
If you're interested in the set please see our store at www.rtl-sdr.com/store, or use the links provided in Tom's videos. We also have a tutorial and use case demonstrations for our dipole kit available at www.rtl-sdr.com/DIPOLE.
Over on YouTube user radio innovation has uploaded a brief screen capture showing his Raspberry Pi 3 and RTL-SDR dongle being used as an always-on monitor for low transmit power based signals such as FT8, JT65 and JT9. These signals are transmitted by ham radio enthusiasts for the purpose of making contacts, and determining propagation conditions. This is a good application for an RTL-SDR and Raspberry Pi 3 as it enables cheap monitoring of these signals without the need to tie up a full sized ham radio.
To do this "radio innovation" runs Linrad on the Raspberry Pi, which is a program like GQRX that interfaces with the RTL-SDR dongle. Then the WSJTx software is used to decode the signals. He writes:
Remote Desktop screencapture of my Raspberry Pi3 monitor receiver on 40m amateurradio band with WSJTx and decoding FT8,JT65 and JT9. Receiver hardware is RTL-SDR(tcxo) + simple converter and homemade bandpass filter.
SDR software is LINRAD by SM5BSZ.
RasperryPi3 OS is Ubuntu Mate 16.04.
Update:We now have a tutorial on creating a similar set up available on a new post.
Over the last few years Brazil has been moving over to digital TV, and has planned to shut down the old analogue TV signals. Vinicius Lenci (PU2VLW) was watching with his SDR during the analog shutdown that occurred in Pedreira-SP on the 17th of January 2018 (note that the post is in Portuguese but Google Translate can be used). The video on his post captures the end of an era by eerily showing the analog TV audio signal suddenly cutting off and turning to noise. In another video where he was monitoring 16 analog channels with an analog TV receiver shows the channels slowly switching off one by one within a few minutes.
Shortly after the analog TV signals were shutdown, Vinicius notes that a new digital TV signal under test at 571 MHz appeared in place of one of the old analogue signals. Also he notes that the now empty 750 MHz band will eventually be replaced by mobile LTE technology.
Capturing the Analogue TV shutdown in Pedreira, Brazil.
Recently we've come into knowledge of a program on GitHub called "System Bus Radio" which lets you transmit RF directly from your computer, laptop or phone without any transmitting hardware at all. It works on the principle of manipulating the unintentional RF radiation produced by a computers system bus by sending instructions that can produce different AM tones. An SDR like the RTL-SDR V3 or RTL-SDR with upconverter, or any portable AM radio that can tune down to 1580 kHz can be used to receive the tones. To run the software don't even need to download or compile anything, as there is now a web based app that you can instantly run which will play a simple song.
However, the RF emissions don't seem to occur on every PC, or are perhaps at another frequency. We tested a Windows desktop and Dell laptop and found that no were signals produced. A list of field reports indicates that it is mostly MacBook Pro and Air computers that produce the signal, with some transmitting signals strong enough to be received from a few centimeters to up to 2m away. This could obviously be a security risk if a sophisticated attacker was able to sniff these tones and recover data.
This program runs instructions on the computer that cause electromagnetic radiation. The emissions are of a broad frequency range. To be accepted by the radio, those frequencies must:
Be emitted by the computer processor and other subsystems
Escape the computer shielding
Pass through the air or other obstructions
Be accepted by the antenna
Be selected by the receiver
By trial and error, the above frequency was found to be ideal for that equipment. If somebody would like to send me a SDR that is capable of receiving 100 kHz and up then I could test other frequencies.
There is also an interesting related piece of software based on System Bus Radio called 'musicplayer', which takes a .wav file and allows you to transmit the modulated music directly via the system bus.
If you're interested in unintentionally emitted signals from PCs, have a look at this previous post showing how to recover images from the unintentional signals emitted by computer monitors. This is also similar to RPiTX which is a similar concept for Raspberry Pi's.
The official software package of the SDRplay range of products is SDRuno and it has recently been updated to version 1.22. SDRuno is also compatible with the RTL-SDR.
In addition to some UI improvements for new users, the main changes are pasted below. What's also very interesting is their road map which states that future versions of SDRuno will have frequency scanning capabilities, a remote network streaming server/client implementation and an API for the support of third party plugins. This would improve it's capabilities similar to that of SDR#.
Added • Support for 1366×768 default layout • ADC overload detection in AGC off mode • ADC overload acknowledgment system to avoid lockout condition • Custom step size for each mode • Band Button Groups (Ham Lower, Ham Upper, Broadcast) • Two additional SP1 width presets (2560 and 3840) • Additional menu option in memory panel to reset column widths (helps when upgrading) • Scheduled Recording • Auto update
Changed • Registry reset now only clears 1.2+ entries • SP1 Window max size supports 4K displays (3840×2160) • Small improvements to the memory panel (panel width and field width changes) • Improvements to the IF output mode • UTC time fixed to 24 hour format • Play!/Stop button colour coordinated • Move MUTE button to make way for VOLUME label • Moved Squelch value display to the right
Fixed • Log10 SING error • Aero support detection to try to prevent rendering issues • Freezing when switching to HiZ port in gain mode • Gain “pumping” issue when in gain mode • Settings panels not displaying properly when “un-minimised” • Zoomed in frequency scale drag out of bounds bug • Noise floor measurement bug • Improved RSP error handling • Sample rate change causing spectrum display issues • Device selection bug
Known Issues • SP2 CWAFC drift issue (Zoom/window size/freq display) – will be addressed in 1.23, workaround for now is to zoom out fully in the SP2 window and then the CWAFC feature will work. • IF output mode disabled SP1 spectrum mouse clicks – temporary issue until LO is separated from the VFO (see plans below)
Following on from the 1.21 release where we outlined the features for coming releases, we have updated our plans, as shown below. The purpose of publishing this information is to give people an insight to the development plans but it is NOT a guarantee of the exact feature line-up and we cannot give release dates.
1.23 Intermediate update • Recording of selected signal only (either I/Q or audio) to WAV file format • Selected signal piped to VAC in I/Q format
1.3 Major update • Separation of VFO and LO frequency control • Frequency scanning
1.31 Intermediate update • Remote client for network based streaming I/Q server applications
1.4 Major update • Addition of new API for third party plugins
APL is an old but very concise array oriented programming language that uses mostly special characters to represent functions and operators. Dyalog APL is a modern implementation of APL, and is designed to make it easy to analyse and process large amount of data.
Over on YouTube there has recently been a talk uploaded from the Dyalog17 conference where Moris Zucca talks about using RTL-SDRs with Dyalog APL. In the talk he shows how he processes the RF data in the APL language leading to a reverse engineered garage door opener. The talk slides can be found here and the blurb reads:
Software-defined radio (SDR) is a radio communication system in which components such as amplifiers and modulators are implemented using software instead of the traditional hardware. In the last decade, technological advances by RealTek Labs (RTL) have made SDR viable for hobbyists. Moris Zucca (SimCorp Italiana) is one of the hobbyists who has taken up the RTL-SDR challenge; he explains how he has connected the Dyalog interpreter to various devices and converted the radio signals using APL. A little bit of reverse engineering means that he now possesses possibly the only remote control for a garage door that can be activated using APL!
Exploring the RF spectrum with Dyalog APL - Moris Zucca - Dyalog '17
Over on YouTube FairlawnARC.org have uploaded a talk about SDRs and ham radio by Ria Jairam (N2RJ0). The talk is a good overview of the current state of SDRs for ham radio use, and she discusses the various hardware and software options as well as giving many tips for improving your ham station. The blurb reads:
Our speaker was Ria Jairam (N2RJ), a world class contest operator and member of the Frankford Radio Club. Ria discussed the latest technology and offerings from Flex Radio, the HPSDR project (Ananradios), RTL SDR and others, as well as practical tips for contesting, DXing and rag chewing using your SDR. This presentation was held on Friday, October 20, 2017, 1900 hours at the Fair Lawn Senior Center, 11-05 Gardiner Road, Fair Lawn, NJ. The event was open to the public & refreshments were served.
Ria Jairam, N2RJ YLs, SDR & Setting Up A World Class Station
Part 2 - Ria Jairam, N2RJ YLs, SDR & Setting Up A World Class Station
Over on his site rtl-sdr.ru, Vasilli has been back at work creating new plugins for SDR#. The latest plugin is a TCP server that takes the demodulated mono audio stream from SDR# and sends it over TCP (note that the site is in Russian but the Google translate button on the right can be used). This can be used to easily stream audio over the internet or a network, or even locally on the same PC to another program. If enough programs support TCP audio streams, then the plugin could potentially replace the need for software like Virtual Audio Cable or VBCable by allowing another method for piping the audio from SDR# into a decoding program.
Installing the plugin is the same as usual. Just extract the SDRSharp.TcpServer.dll file to the SDRSharp folder, open plugins.xml with a text editor and paste in the 'magic line' specified in MagicLine.txt.
To test the server you can connect to it with VLC media player. Some special commands need to be specified to VLC in order for it to understand the audio format. To enter them go to Media->Open Network Stream and make sure 'Show more options' is checked. Enter the network URL as 'TCP://127.0.0.1:20022' (without quotes), and enter the Edit Options field as ':demux=rawaud :rawaud-channels=1 :rawaud-samplerate=48000 :rawaud-fourcc=s16l' (without quotes). Ensure the first colon in the line is copied over properly. Then enable the TCP server in the SDR# plugin, and click Play in VLC. Ensure the SDR# is muted, and the volume in VLC turned up. Audio should now begin streaming through TCP.
Hopefully in the future we can see some audio compression algorithms and more decoding software supporting TCP audio connections.
Vasilli has also updated many of his other plugins too, including creating a DSD_TCP plugin which allows you to transmit the digital audio directly to DSD+ via a TCP connection.
