In his latest YouTube video Tech Minds explains and demonstrates Remote SDR V2, which is software that allows you to easily remotely access either a PlutoSDR, HackRF or RTL-SDR software defined radio. It is designed to be used with the amateur radio QO-100 satellite, but version 2.0 now include multiple demodulation modes, NBFM/SSB transmission capability, CTCSS and DTMF encoders, modulation compression and a programmable frequency shift for relays.
In his video Tech Minds shows how to install Remote SDR V2 onto an Orange Pi via the SD card image, how to access the web interface, and how to access and use the connected SDR.
Remote SDR V2 with Orange Pi and Transmit Capable
We note that the code is designed to be run on Orange Pi boards, which are low cost single board computers similar to Raspberry Pi's. However over on Twitter @devnulling has indicated that his own fork of the code should run on x86 systems. Aaron @cemaxecuter is also working on including it into a DragonOS release.
The image below demonstrates a typical Remote SDR V2 transceiver setup with two HackRFs.
A full QO-100 Transceiver Setup with Remote SDR V2 and two HackRF's.
Recently SDR-Boston hosted an online panel titled "Lessons Learned – Using SDR in the Classroom", and the video is now up on YouTube. A presentation was given by three panelists and moderator on the topic of how software defined radio has been used in University curriculum. Many of the courses make use of RTL-SDR dongles, as well as more advanced transmit capable SDRs.
Software-defined radio (SDR) technology is extensively being used across a wide range of research activities to help demonstrate feasibility of new algorithms and approaches that are rapidly defining the new current state-of-the-art in emerging wireless technologies (e.g., 5G/6G, drone networks) as well as providing new opportunities to explore the electromagentic (EM) spectrum world around us (e.g., radio astronomy, satellite communications, radar). Although SDR has become mainstream in research activities, it has not been widely used in the classroom environment to help students leap from theoretical concepts to practical hands-on learning.
The following presentations were given (more information available on the panel website):
1,024 ways to teach with SDR: Dr. Fraida Fund, New York University
Educators who are considering using software defined radio in the classroom face a dizzying array of choices, including hardware, software, and curriculum decisions. In this presentation, I will describe my experiences using software defined radio in different ways for a range of audiences, from high school to graduate school. I will share the decisions I made in designing each course or curriculum module, and the tradeoffs associated with those decisions.
Teaching SDR and DSP to Undergrads within CS: Dr. Marc Lichtman, University of Maryland
Dr. Lichtman will briefly discuss the course he designed and taught at The University of Maryland within the CS dept, introducing students in their senior year to SDR and DSP, as an elective. The first half of the course acts as a DSP and wireless comms primer, essentially condensing several courses that are normally taught at the graduate level within ECE, providing students with the necessary background by teaching DSP theory using diagrams, animations, practical demos, and code examples rather than a mathematically rigorous theoretical approach. The remainder of the course focuses on using SDRs to implement the DSP techniques they had learned. He has recently created a free online textbook based on his course, teaching SDR and DSP with Python, https://pysdr.org.
Teaching Introductory Communication Systems using SDR: Challenges, Benefits, and Lessons Learned: Dr. Cory J. Prust, Milwaukee School of Engineering
Exposure to software-defined radio (SDR) technology is a valuable experience for undergraduate electrical and computer engineering students. Decreasing hardware costs and easy-to-use software tools have made SDR experimentation readily available to the undergraduate laboratory setting. However, especially for students who are still learning the fundamentals of communication systems, laboratory exercises must be carefully designed to reinforce foundational concepts, meaningfully engage and motivate students, and be presented at an appropriate technical level. This presentation will describe the development and deployment of hands-on SDR-based laboratories used in an introductory communication systems course. Lessons learned from multiple offerings of the course will be discussed.
Hands-On Wireless Communications Education: It’s More Than I/Q Representation: Dr. Alexander M. Wyglinski, Worcester Polytechnic Institute
In most undergraduate and graduate courses focusing on digital communication systems engineering, the concept of representing all information in terms of in-phase (I) and quadrature (Q) comes up and becomes the foundation for many other concepts taught throughout the rest of the course. However, the treatment of I/Q tends to be over idealized and the real-world effects affecting this very important source of information is saved “for the next course”. With SDR technology, those real-world effects that are impacting the successful recovery of I/Q samples are experienced right away and the true challenges of digital communication systems engineering are experienced first hand. This introduction will provide some initial insight on the practical considerations when extracting I/Q samples from over-the-air and attempting to decode them for the purposes of recovering binary information.
SDR-Boston Panel Event: "Lessons Learned - Using SDR in the Classroom"
In his latest video Rob from Frugal Radio has reviewed the NooElec Inmarsat Patch Antenna Bundle. The US$79.95 bundle includes a PCB patch antenna, Inmarsat SAWBird LNA, SMA DC Block, SMA Barrel adapter and SMA pigtail. In the video Rob tests the bundle out on various AERO signals using the JAERO software, before moving on to compare the bundle with our own RTL-SDR Blog Active L-Band Patch antenna. The comparison results show that our $49.95 L-band antenna is better by about 5-6dB in SNR.
Our RTL-SDR Blog Active L-Band Patch antenna set is available on our store. However, please note that this antenna is currently in short supply due to the global electronics supply chain shortage. We expect to be sold out within a few days but we are aiming to be able to restock within 1-2 months from now.
Review : NooElec L Band Inmarsat Patch Antenna Bundle
Thank you to Mitsunobu for writing in and sharing news about the release of his new product which is a Hi-Z (high impedance) to 50 Ohm matching transformer. This transformer allows you to use small antennas such as short telescopic whips for HF/SW reception on software defined radios.
Generally for HF reception you would want to use a full sized antenna, which can be many meters long and certainly not portable. However, by using an high impedance transformer it becomes possible to use smaller portable antennas. Reception with a small antenna and transformer will still be suboptimal compared to a full sized HF antenna, however, if the signals are strong enough the transformer will allow you to receive them decently.
In the tests shown on his blog (in Japanese, use Google Translate) he shows how the transformer adapter can be connected to a small telescopic whip and Malachite DSP SDR for portable use. Later he also shows how the adapter can make our Dipole Kit antenna work well for HF on a RTL-SDR Blog V3 with direct sampling.
Rob from Frugal Radio has recently uploaded the next episode in his excellent YouTube series on Aviation monitoring. In this episode Rob covers HF aviation communications. Rob writes:
Whether you are using a Software Defined Radio (SDR), an old school HF receiver, or utilizing a WebSDR, there is plenty to monitor when you know where to look.
This video will give you the basics of where to find the Aviation Communications that take place from 3-30 MHz (HF / Shortwave).
This episode covers VOLMET broadcasts, the Major World Air Route Areas (MWARA), and Military Nets like the US Global Communications System (HFGCS).
Remember, these signals travel thousands of miles. It can be quite exciting to receive them over such great distances. When editing this video I was listening to a VOLMET station in Auckland, New Zealand - a distance of over 7500 miles (12,200km) away!
Monitoring HF Aviation Voice Communications with your SDR Radio or a WebSDR
As a follow on to the previous post on fake SDRplay units, we also wanted to provide some guidance on fake RTL-SDR Blog V3 clones which are on the market. We are starting to receive an increase in support requests for fake RTL-SDR Blog V3 units. Please be aware that we cannot support these devices, and most of them are missing key features like the bias tee and the TCXO despite advertising these features on the listing and writing on the dongle body. Also as mentioned below a good majority of them appear to have a defect and poor performance.
Please check our store at www.rtl-sdr.com/store for our official stores on Amazon, eBay, Aliexpress and this site. We also have links on our store to our official local resellers.
We note that we tested a few of the "RTL.SDR" clones, and all had a defect causing very strange distorted spectrums where the signals where wider than they should be, and some units introduced a mysterious high pitched whine into every signal.
Spectrum from cloneSpectrum of an original RTL-SDR Blog V3
To be clear, different brands of RTL-SDR are perfectly fine - no one owns the RTL-SDR hardware concept and we are not any more "official" than any other brand (although we believe we were the first to start designing and producing significantly improved units and the first to design in a factory fitted TCXO, SMA connector, bias tee, thermal pad, and a redesigned PCB for lower noise and less spurs).
However, these clones shown in the image above can be considered a sort of scam as they attempt to trick buyers into believing that they are purchasing our RTL-SDR Blog V3 units with false advertising and by copying the enclosure design, when in fact the PCB inside is something inferior.
2021 Supply Chain Updates
As many of you may know the world is currently dealing with a major shortage of many electronics parts so we wanted to provide an update on the supply chain for the RTL-SDR Blog V3.
In particular, the world is very short on temperature compensated oscillators (TCXO's), a critical component used in our units to ensure frequency stability. The TCXO shortage is actually much worse than other components as AKM, the Japanese semiconductor factory that produces a critical component for making TCXOs burned down late last year. There are alternative suppliers, however their pricing is many multiples higher, and they are also inundated with orders increasing lead times.
We believe that we have enough TCXO stock in storage to last us several more months, however we may run into a shortage in the later months of this year. After we expend our current TCXO stock, we expect to have TCXO again around December, with more RTL-SDRs being ready by January 2022. We want people to be aware, as during these months of no stock more clones may appear on the market. Most clones do not use TCXOs, and hence have poor frequency stability.
Also on a related note our Amazon stock levels may be a little spotty throughout this year as there are currently often delays with shipping and the ports.
We also note that other products that we resell on our store such as the FlightAware Prostick Plus and NanoVNA V2+ are also experiencing supply issues, and may not have stock for a while. Production of some of our other products like the L-band Patch are also delayed due to shortages.
Due to the shortages component prices are also significantly increasing, and you may notice an increase in RTL-SDR pricing from us and competitors too. We hope that we will be able to reduce our pricing again once the global shortage is over, most likely around early next year.
The ##rtlsdr IRC Freenode chat channel will be moving to irc.libera.chat. However ##rtlsdr admins note that the Freenode channel will remain open for now. This move is in wake of the recent takeover drama surrounding Freenode, and the resignation of the majority of Freenode staff.
The ##rtlsdr IRC channel is where many RTL-SDR, software defined radio and RF enthusiasts hang out. You can join and idle with any IRC client, or a web client is available at https://kiwiirc.com/nextclient/irc.libera.chat/##rtlsdr.
A discussion about the move has also been opened on Reddit /r/rtlsdr.
Many other related project channels such as #gnuradio are also moving over to Libera.
Over on his YouTube channel saveitforparts has uploaded a video showing how he has built an automated weather satellite image collector for the NOAA APT and Meteor M2 LRPT satellites. The video shows a time lapse of him building a QFH antenna, and how he's mounted a Raspberry Pi and RTL-SDR inside a waterproof enclosure attached to the antenna mast. He goes on to show how he's automating the system with the Raspberry-NOAA V2 software.
Automated Home Weather Station (Satellite Image Collector)
