Community member Luigi Cruz has written up how he modified a LimeNET Micro to take part in the Galmon global navigation satellite system (GNSS) monitoring network.
“In this blog post, I will explain how I managed to get a GNSS multi-constellation monitor called Galmon working on my LimeNET Micro,” Luigi explains by way of introduction to the project, which was discussed in brief in an earlier OTA. “The Galmon project is a crowdsourcing tool developed by @PowerDNS_Bert to monitor the health status of GNSS constellations including the GPS, GLONASS, BeiDou and more notably Galileo. The project relies on volunteers to set up inexpensive stations based on the Ublox-M8 module to receive GNSS packets and send diagnostic data back to an aggregator.”
Luigi’s project relies on accessing the LimeNET Micro’s on-board GNSS module bidirectionally, rather than simply listening to its output. A quick hardware modification – “quite easy to make using a cheap fixed temperature soldering iron,” Luigi explains – and the LimeNET Micro was ready to run a Galmon node. The software, which includes a browser-based dashboard, pulls in information on “current satellites being received by your station in real-time [including] a bunch of cool diagnostics for each satellite, like health status, elevation, signal-to-noise ratio, and ephemeris age.”
The full write-up is available on Luigi’s blog.
QRadioLink 0.8.0 has been officially released, following two weeks of release candidate testing, and it brings with it new FreeDV digital modes, an upgraded GNU Radio, performance improvements, and an overhauled user interface.
First announced by Adrian Musceac earlier this month, QRadioLink 0.8.0 represents a major revamp of the popular software package including an entirely new user interface. “The new interface gets rid of the GNU Radio Qt GUI elements and is based entirely on Qt5,” Adrian explained at the time. “Of course, QRadioLink still supports the LimeSDR and Lime-mini through SoapySDR.”
Since the initial 0.8.0 commits were made to the project’s GitHub repository, there have been three Release Candidate (RC) builds. The first introduced the new user interface, increased the sample rate range, improved performance, and added new configuration options; the second release candidate addressed reported issues, while the third addressed still more including missing duplex operation functionality and the lack of audio compressor.
Now, QRadioLink 0.8.0-2 has been released as the latest non-RC build, bringing with it some improvements over the Release Candidate versions: the software has gained support for FreeDV 1600 and FreeDV 700C digital modes, the fast Fourier transform (FFT) code performs better, and the build is now based on GNU Radio 3.7.13 and Qt 5.13.
The new build is available now on the QRadioLink website.
AMSAT-DL has passed on a warning from the operators of the QO-100 Es’hail-2 satellite, following the detection of radio amateurs operating uplinks at too high a power level.
Launched in November 2018, Es-hail-2 – now known under its operational identifier of QO-100 – carries amateur radio transponders which have proven popular for a range of projects and experiments. Unfortunately, the future of these transponders is at risk unless users pay attention to the power levels of their uplinks and downlinks.
“This morning (around 05:25-05:33 UTC, 2019-09-22) alarms were triggered in the Es’hailSat satellite control centre in Qatar due to High Power uplink on the NB transponder,” writes AMSAT-DL president Peter Guelzow. “Considering the safety of transponder they may SWITCH OFF the QO-100 transponder in case if it exceeds the limits again. Please accept and respect the transponder guidelines rules and band plans.
“Please stop running high power, even not for experiments or try-out! If you want to test your power, please use a dummy load and power meter. Keep your Downlink strength at the same level as the CW Beacon, maximum one S-Unit above will be tolerated! Stay within the borders of the transponder. Do not transmit below the CW Beacon and do not transmit above the PSK Beacon! Please help everyone on QO-100 to adjust operation practices accordingly. Please be friendly and polite with other OMs on QO-100, but don’t hesitate to give them reports.”
More information is available on the AMSAT-DL forum.
David Rowe, Gerhard Burian, and Steve Sampson have been experimenting with transmission of FreeDV 2020 over QO-100, using a LimeSDR USB for transmission.
“Gerhard (OE3GBB), Steve (K5OKC), and I have been working on FreeDV 2020 over the Es’hail 2/QO-100 satellite,” David writes. “This satellite is in geosynchronous orbit and has a linear transponder. It’s designed for SSB so has a narrow bandwidth which rules out most digital voice modes – except FreeDV. For example FreeDV 2020 can send 8 kHz wide speech over just 1600 Hz of RF bandwidth. A linear amplifier also means the OFDM waveforms used by FreeDV will pass OK, as long as your transmit system is linear.”
While initial experiments with FreeDV 1600 worked, FreeDV 2020 proved more challenging. “We guessed that this was due to significant phase noise on the channel, from the many up and down conversion steps and the transponder itself. Fortunately the SNR was quite high,” David explains. “Steve and I modified the OFDM modem used for FreeDV 2020 to handle this.”
“The quality is quite high, and through a nice set of speakers the wide, 8kHz audio bandwidth is very pleasant. However I can hear some frame rate modulation, and I’ve heard similar on some other 2020 samples over HF channels from the US test team. I’ll explore that at some stage.”
David’s full write-up is available on rowetel.com.
Tauris-1, a satellite carrying an amateur radio FM to Codec-2 transponder, was successfully launched earlier this month – though its transponder has yet to be activated.
Launched from the Taiyuan Satellite Launch Centre on a CZ-4B rocket on the 12th of September, Taurus-1 – also known as Jinniuzuo-1 – is carrying an amateur radio FM to Codec-2 transponder, similar to that used on the LilacSat-1 satellite: FM signals received on 145.82 MHz are retransmitted as Codec-2 signals at 9600 bps on 436.76 MHz with telemetry available on 435.84 MHz.
“Good signals from Taurus-1 on 435.840 MHz,” Mark Jessop writes on Twitter of his initial testing. “Doesn’t look like the FM/Codec2 Transponder is enabled yet though – no response on 436.760 MHz when transmitting on 145.820 MHz.”
More information on the satellite, including information on receiving the downlink, can be found on Southgate Amateur Radio News.
Videos of the Martlesham Microwave Round Table presentations have been published on YouTube, including a look at Practical GNU Radio, transmission and reception of QO-100, and a low-pass harmonic filter for 23 cm use.
Now available on the Martlesham Microwave YouTube channel, the videos cover six presentations and discussions made during the event: Practical GNU Radio by Heather Lomond; From Death-Rays to Dinner by William Eustace; Equipment for Es’hail-2/QO-100 Narrowband by David Bowman; DATV on Es’hail-2/QO-100 by Noel Matthews; a Low-Pass Harmonic Filter for 23 cm by John Quarmby; and the UK Microwave Group (UKuG) SDR Voice Transceiver Project discussion session.
All six videos are available to view now on the Martlesham Microwave YouTube channel.
Hackaday has drawn our attention to a project to create a hackable electronic multi-tool for the radio amateur – the Antuino.
“Antuino is an accurate instrument that can be used in the field to measure SWR, field strength, modulation, etc. In the lab, it can be used to sweep filters, measure gain, distortion, frequency response, etc.,” explains creator Ashhar Farhan. “It works upto 150 MHz. On the third harmonic, it is usable on 435 MHz band as well (with reduced sensitivity).
“The Antuino, unlike simpler instruments is based a superhet architecture that measures the response of the antenna or circuit at exactly the tuned frequency. It is based on Analog Devices’ Logarithmic Amplifier, the AD8307 to provide accuracy of 1 dB in your measurements. It is tuned with a crystal locked PLL based on Si5351 oscillator chip.”
“Most of the active ham radio operators today are of the grey haired, retired variety. If the hobby is to stand any chance of outliving them, it needs to find a way to be attractive to the younger generations who grew up with the internet,” writes Hackaday’s Danie Conradie of the project. “The availability of affordable and hackable equipment can go long way to making this happen, and Ashhar Farhan has been one of the biggest contributors in this regard.”
The Wireless Broadband Alliance and the LoRa Alliance have released the results of a joint study investigating how high-bandwidth Wi-Fi and low-power long-range LoRaWAN can support each other in various Internet of Things (IoT) deployment scenarios.
“Wi-Fi and LoRaWAN are two important technologies utilising the unlicensed spectrum, and they already address a large proportion of IoT use cases,” says Tiago Rodrigues, general manager of the WBA. “The Deployment Synergies paper highlights the ways in which these technologies are impacting private-public business models and enabling IoT services, while also identifying ways in which the technologies complement one another and can be used to further expand the Internet of Things.”
“The reality is that no one single technology is going to fit the billions of IoT use cases,” adds Donna Moore, chief executive and chair of LoRa Alliance. “It is collaborative initiatives like this one with Wi-Fi that will drive innovation to solve important issues, leverage an even broader range of applications and, ultimately, ensure the success of global mass IoT deployments in the future.”
The white paper itself is available to download from the LoRa Alliance website.
The US Federal Communications Commission (FCC), Wireless Telecommunications Bureau (WTB), and Office of Engineering (OET) have approved the first commercial deployments in the 3.5 GHz band as part of the Citizens Broadband Radio Service (CBRS).
The approval notice provides five system administrators – confirmed as Amdocs, CommScope, Federated Wireless, Google, and Sony – with permission to open spectrum access services (SAS) in the 3.5 GHz band for initial commercial deployments (ICDs), following the completion of labs testing in May this year.
“We are thrilled to have reached this milestone for Initial Commercial Deployments of services and devices in the Citizens Broadband Radio Service,” say Wireless Telecommunications Bureau chief Don Stockdale and Office of Engineering and Technology chief Julius Knapp in a joint statement. “It is the result of a successful coordinated effort between industry and government that breaks new ground in spectrum management and is a major step in paving the way for 5G. We extend our congratulations to all of the many people who played a role in getting us to this point.”
Full details are available in the FCC’s public approval notice.
The GSM Association (GSMA) has announced the launch of an Inclusive Tech Lab, designed to improve access to telecommunications and financial technologies, with three years guaranteed funding from the Bill & Melinda Gates Foundation.
“In launching the GSMA Inclusive Tech Lab, we are taking a bold new step to support and stimulate innovation through greater experimentation and a willingness to take risks,” says John Giusti, chief regulatory officer at the GSMA. “The GSMA Mobile for Development programme has already had a direct impact on improving the lives of 58 million people. The Lab will allow our team of dedicated ‘technopreneurs’ the opportunity to take a hands-on approach to break down the barriers to economic and social inclusion further.
“Today there are challenges of expanding access to financial services, bridging the digital services gap for women and vulnerable user groups, and providing digital identity solutions for the one billion individuals with no form of ID. These challenges drive our activity as we work on the transformative digital innovations of tomorrow.”
“We are proud to be collaborating with the GSMA and funding the Inclusive Tech Lab to strategise, build, and pilot technologies to support the industry with innovations to drive financial inclusion for the poorest,” adds Matt Bohan, senior programme officer for Financial Services for the Poor at the Bill and Melinda Gates Foundation. “The Lab will enable us to create and explore products, from interoperability platforms to standardised APIs and more, that will help the industry to drive innovation to include poor people at a whole new pace and scale.”
The first output of the lab, which is open to projects from industry and academia, is expected in the first quarter of 2020. More information, including how to apply, can be found on the GSMA website.
Amazon has announced it is getting into the wireless protocol business, launching a low-bandwidth long-distance protocol for the Internet of Things dubbed Sidewalk.
Unveiled during an event at which Amazon showcased a range of network-connected smart devices, including low-cost smart home accessories and wearable devices imbued with connectivity to the company’s Alexa voice-activated assistant platform, Sidewalk is designed to operate in the 900 MHz spectrum. “We think it will be great for keeping track of things, keeping things up to date,” Amazon’s Dave Limp claimed during the unveiling, “but first and foremost, it will extend in the distance at which you can control these kinds of simple, low-cost, easy-to-use devices.”
Technical details on Sidewalk have not yet been made available, though the company has pledged to publish the protocol for third-party adoption, though the company claims that testing of 700 Sidewalk-enabled devices in LA showcased a range of about a mile. The first commercial Sidewalk product, meanwhile, is to be the Ring Fetch, a dog-tracking accessory for pet owners.
Finally, RTL-SDR has drawn our attention to a plugin bundle for SDR# which pulls in some of the most popular plugins automatically during installation.
Maintained by Rodrigo Pérez, the SDR# Community Package includes the latest SDR# software along with a collection of the most popular community plugins: a baseband recorder, DDE tracker, digital audio processor, frequency manager, connector for Gpredict, level meter, network remote, and support for the LimeSDR family of software defined radios – making it a one-step installation for those looking to use a LimeSDR with SDR#.
The latest community build is hosted on the SDR# download page, just under the plain Windows download. It will be updated as new plugins and SDR# releases are made available.