The LimeRFE software-definable RF front-end has officially passed verification in its updated v1.0 revision form, with production of the backer boards on-track for a late-January shipping schedule.

As detailed back in August, the LimeRFE board – which offers low-noise amplification, power amplification, and filtering under software control from the LimeSDR and LimeNET families of software defined radios – is entering into production as a slightly modified design. Compared to the prototype, the LimeRFE v1.0 includes additional amateur radio band support: 50/70 MHz, 220 MHz, and 920 MHz, plus an enhanced 1280 MHz band. A hardware tweak requires, naturally, reverification ahead of mass production – and that verification is now complete.

“We are pleased to report that we’ve verified the 1v0 hardware design, and the first production boards have gone out to developers to facilitate application integration,” Lime Micro’s Andrew Back explains. “However, we are now waiting for a few remaining parts to arrive before we can assemble the backer boards. At the present time, it looks as though orders will ship toward the end of January, but we hope to have a firmer date soon and will provide a further update as soon as we do.”

More information on the project can be found on the Crowd Supply campaign page.

A fresh Field Report has been posted on the LimeSDR Mini Crowd Supply page, this time in video form courtesy of Signals Everywhere host Harold Giddings.

In the two-part video series, Harold investigates creating a DIY television station – specifically, transmission of DVB-S digital TV signals – using a LimeSDR Mini and affordable and common extras: a webcam, a laptop, and a low-cost satellite receiver dongle for the reception side, with software provided via DATV Express. Interestingly, Harold’s setup doesn’t include a low-noise block downconverter (LNB) – an tricky omission he explains during the video series.

More information on the Field Report, including both videos, can be found on the LimeSDR Mini Crowd Supply campaign page.

Community member Daniel Estévez has written of his efforts to measure the Allan deviation of a GPS disciplined oscillator (GPSDO) using a LimeSDR USB – following unsuccessful attempts to use a particular GPSDO to measure QO-100 NB transponder LO stability.

“A few days ago I tried to measure the QO-100 NB transponder LO stability using my DF9NP 10MHz GPSDO. It turned out that my GPSDO was less stable than the LO, so my measurements showed nothing about the QO-100 LO,” Daniel explains. “Carlos Cabezas EB4FBZ has been kind enough to lend me a Vectron MD-011 GPSDO, which is much better than my DF9NP GPSDO and should allow me to measure the QO-100 LO.

“Before starting the measurements with QO-100, I have taken the time to use the Vectron GPSDO to measure the Allan deviation of my DF9NP GPSDO over several days. This post is an account of the methods and results. I am using a LimeSDR-USB to compare the phases of the GPSDOs 10MHz outputs. To do so, the DF9NP GPSDO 10MHz output is used as an external reference in the LimeSDR as described in this post. The 10MHz output of the Vectron GPSDO is connected to the RF input of the LimeSDR through sufficient attenuation.

“This attenuation is provided by a Mini-Circuits ZFDC-10-1 directional coupler as follows: the OUT port is connected to the GPSDO 10MHz output, the IN port is terminated with a 50 Ohm load, and the CPL port is connected to the LimeSDR-USB. This is another less than ideal solution, but it gives lots of attenuation. The LimeSDR-USB is tuned to 9.9MHz with a sample rate of 2Msps. This is possible by setting the LO to 30MHz, running with 32x oversampling, so the DAC rate is 64Msps, and using the NCO at -20.1MHz. This allows us to receive the 10MHz signal from the Vectron GPSDO at 100kHz in the IQ baseband.”

Full details of the measurements, including a GNU Radio flowgraph and the final results, can be found on Daniel’s blog.

Presentations from the DEF CON 27 Wireless Village have now been made available for streaming on YouTube, with 15 videos covering topics from Wi-Fi access point vulnerabilities to antennas for surveillance.

Taken from the recent DEF CON 27 hacker conference, the videos cover a range of topics: Several investigate Wi-Fi access point development and the security behind them, including one which proposes a new defence system for same; others look more at antenna systems, or wireless vulnerabilities in physical access control systems; one even investigates reverse-engineering of a wireless model railway control system.

All videos are available to stream now on the official DEF CON YouTube channel.

Researchers from Korea’s Sungkyunkwan University and Hallym University have published a paper on nano-scale radio frequency antennas they claim will prove invaluable for wearable electronics projects.

“The state-of-the-art of the Internet of things (IoT) and smart electronics demands advances in thin and flexible radio frequency (RF) antennas for wireless communication systems. So far, nanostructured materials such as metals, carbon nanotubes, graphene, MXene, and conducting polymers have been investigated due to their noteworthy electrical conductivity,” the researchers explain in the paper’s abstract. “However, most antennas based on metallic materials are thick, which limits their application in miniaturised and portable electronic devices.

“Herein, we report two-dimensional (2D) metallic niobium diselenide (NbSe₂) for a monopole patch RF antenna, which functions effectively despite its sub-micrometer thickness, which is less than the skin depths of other metals. The as-fabricated antenna has an 855 nm thickness and a 1.2 Ω sq⁻¹ sheet resistance and achieves a reflection coefficient of −46.5 dB, a radiation efficiency of 70.6%, and omnidirectional RF propagation. Additionally, the resonance frequency of this antenna at the same thickness is reconfigured from 2.01 to 2.80 GHz, while decreasing its length and preserving its reflection coefficient of less than −10 dB. This approach offers a facile process to synthesise 2D metallic transition metal dichalcogenides for the rational design of flexible, miniaturized, frequency-tunable, and omnidirectional monopole patch RF antennas for body-centric wearable communication systems.”

The resulting antenna, created by coating a plastic substrate with NbSe₂, is claimed to perform acceptably at just 10x10mm with an 855nm thickness. Full details are the paper, published in the journal ACS Nano.

RTL-SDR has drawn our attention to demonstrations from Bastian Bloessl of GNU Radio running on an Android smartphone – with no need for root access.

The Linux-based Android operating system is powerful, but some of that power is locked behind a system which prevents the user from making deeper changes to how it operates. A common practice is to ‘root’ Android-based devices – gaining access to the root user account – but doing so can bring unwanted side-effects, including disabling some applications or preventing over-the-air updates.

Bastian’s project, then, is to get GNU Radio running on an Android smartphone without rooting – and appears to be succeeding. In a recently-published video, Bastian shows GNU Radio 3.8 interfacing with a common USB-connected software defined radio – and entirely without the need to run as the root user. Even the display is hardware-accelerated.

Details haven’t yet been provided, nor a download, but Bastian is posting about the project on his Twitter account for those looking to follow his progress.

The Osmocom project has made a range of announcements in the last few days, including new features for the OsmoSTP signal transfer point package, the successful test of a breakout board for WWAN modems, and the publication of binary downloads for Ubuntu 19.10 and the latest Raspbian operating systems.

“OsmoSTP has received a variety of new features over the last few weeks,” project maintainer Harald Welte explains in a project update. “This includes: operation of STP in M3UA ASP role (normally a STP operates in SG role); operation as STP in STCP client/connect role (normally a STP operates in SCTP server/bind); support for SCTP multi-homing with configurable IPs on local and remote end; make point-code insertion into SCCP optional at for IPA ASPs; dynamic creation of ASPs within an IPA/SCCPlite AS; support traffic-mode load-share (in M3UA and IPA).

“We had recently received the prototype v2 of the m.2/NGFF WWAN modem breakout board and are happy to report that it immediately worked for both USB 3.0 super-speed as well as for PCIe,” Harald writes in a separate update. “All debug results and reworks from v1 have been incorporated in this v2. Design validation has completed, which means a first manufacturing batch is in up in the pipelnie, and we expect boards to become available from the sysmocom webshop in some 4-6 weeks (maybe a bit later due to Christmas holidays).”

Those running Canonical’s latest Ubuntu 19.10 or the Raspbian operating systems, meanwhile, will be pleased to hear of precompiled binaries of the Osmocom stack, provided in both stable and nightly builds through the OpenSuSE Build Service. Full details, and links to download, are available on the Osmocom website.

The Radio Society of Great Britain (RSGB) is to host a winter introduction to amateur radio at Bletchley Park, one-time home to World War II codebreakers at what was then designated Station X.

“The Radio Society of Great Britain (RSGB) at the National Radio Centre at Bletchley Park is pleased to offer a new workshop: An Introduction to Amateur Radio,” the event’s organisers write. “This introductory workshop is intended to give delegates a greater understanding of amateur radio, where there will be specialist people on hand to discuss how to get involved in this interesting hobby.

“The workshop will involve of a mix of introductory talks, videos and demonstrations, with the morning session being held in a classroom environment. After the workshop, delegates will have the opportunity to visit the RSGB’s National Radio Centre (located within Bletchley Park) to see an amateur radio centre in action.”

Details of the event, which is scheduled for Saturday the 14th of December, can be found on the Bletchley Park website.

Finally, researchers at the University of California at San Diego (UCSD) have unveiled a nanowatt wake-up receiver which they claim could dramatically improve the battery life of Internet of Things (IoT) devices.

“”The problem now is that these devices do not know exactly when to synchronise with the network, so they periodically wake up to do this even when there’s nothing to communicate. This ends up costing a lot of power,” explains Professor Patrick Mercier of the problem facing network-connected IoT devices which don’t require constant monitoring. “By adding a wake-up receiver, we could improve the battery life of small IoT devices from months to years.”

The result of Prof. Mercier’s team’s work is a wake-up receiver which draws 22.3 nanowatts while listening for a signal to wake up the main transceiver. While not the first such device, it is claimed to operate at a considerably wider temperature range than previous efforts – between -10°C and 40°C – while introducing just 540ms of delay compared to signalling the main radio directly.

“These numbers are pretty impressive in the field of wireless communications – power consumption that low, while still retaining temperature-robustness, all in a small, highly sensitive system — this will enable all sorts of new IoT applications,” Prof. Mercier claims. “You don’t need high-throughput, high-bandwidth communication when sending commands to your smart home or wearables devices, for example, so the trade-off of waiting for a mere half a second to get a 100,000x improvement in power is worth it.”

More details are available in the team’s paper, published in the IEEE Journal of Solid-State Circuits.