Over on the crowd funding site crowdsupply.com there have recently been several updates on the Fairwaves XTRX SDR. The XTRX is an upcoming TX/RX capable SDR in a tiny Mini PCIe form factor. Mini PCIe is the expansion slot system used on some laptops. The SDR itself will be 2 x 2 MIMO, with a tuning range of 10 MHz - 3.7 GHz (down to 100 kHz with some degradation), and have a sample rate of up to 120 MSPS. It uses the LimeSDR RF chipset which provides most of the hardware required.
The XTRX is not yet for sale, and is planned for a crowdfunding run on Crowdsupply 'soon'. You can subscribe to future updates on their page. No word yet on pricing, but according to one of the developers comments on Reddit the price will be somewhere between the LimeSDR ($299 USD) and LimeSDR Mini ($139 USD). Eventually in the future if they can tap into a mass market they hope to get the price down to $50 USD.
Features & Specifications
RF Chipset: Lime Microsystems LMS7002M FPRF
FPGA Chipset: Xilinx Artix 7 35T
Channels: 2 × 2 MIMO
Tuning Range: 30 MHz - 3.8 GHz
10 MHz - 3.7 GHz
100 kHz - 3.8 GHz with signal level degradation
PCIe x2 Gen 2.0: 8 Gbit/s
PCIe x1 Gen 2.0: 4 Gbit/s
PCIe x1 Gen 1.0: 2 Gbit/s
Sample Rate: ~0.2 MSPS to 120 MSPS
Frequency: 26 MHz
Stability: <10 ppb stability after GPS/GNSS lock, 500 ppb at start up
Form Factor: full-size miniPCIe (30 × 51 mm)
Bus Latency: <10 µs, stable over time
Synchronization: synchronize multiple XTRX boards for massive MIMO
The idea is to keep the barrier of entry to SDR as low as possible, by making SDR programming accessible to kids as well. The software is currently a work in progress, but they write that they are attempting to develop the Scratch blocks necessary to enable the transmission and reception of text messages. Something like that would make a great learning tool for educators.
The video demo shows Scratch and the LimeSDR running on a Raspberry Pi 3. During the demo he creates a simple 433 MHz spectrum display by connecting up several blocks.
The LimeSDR Mini is a smaller and cheaper version of their LimeSDR which has slightly reduced specifications. The main changes are the slightly restricted frequency range of 10 MHz – 3.5 GHz, and half the maximum bandwidth at 30.72 MHz. The mini also only has 1×1 TX/RX channels.
Recently the LimeSDR was released for crowdfunding on crowdsupply.com and already has raised $165,000 of it’s $100,000 threshold with 12 days remaining. Currently you can back the project for $139 with shipping expected on Dec 31.
Just last week we posted about how Marty Wittrock was able to get his LimeSDR receiving perfectly on his LattePanda mini Windows 10 PC with SDRAngel. Now Marty has uploaded a new video which shows the LimeSDR running on the LattePanda and SDRAngel again, but this time transmitting 40m LSB voice. At this stage Marty is well on his way to creating a fully portable LimeSDR based ham transceiver. He writes about his setup:
Setup: LattePanda Win10/64-bit, LCD, Capacitive Touchscreen, LimeSDR and SDRAngel Win32 with a transmit device loaded…Also using a USB 2.0 audio device to make the microphone and speaker audio connections…WORKS GREAT..!!
The LimeSDR is a RX and TX capable SDR with a frequency range of 100 kHz – 3.8 GHz, bandwidth of up to 61.44 MHz, 12-bit ADC and 2×2 RX/TX channels. Recently the LimeSDR team have been crowdfunding for their new ‘LimeSDR Mini’ which is a smaller and cheaper feature reduced version of the standard LimeSDR. While all the early bird $99 USD units have been sold out, they are still available at the $139 USD price. Currently the crowdfunding campaign has already reached it’s $100,000 USD target with 35 days left.
One important ‘feature reduction’ to note is that the LimeSDR Mini can only tune down to 10 MHz, so it may not be as useful as the full $289 USD LimeSDR for creating a SDR based ham transceiver like what Marty is doing.
Thanks to Marty Wittrock for sharing with us his latest news about his experiences with the LimeSDR. Over on YouTube he’s uploaded a video showing that the LimeSDR can run perfectly on a ‘LattePanda‘ which is a full Win10 64-bit PC in a Raspberry Pi sized package. The one Marty uses costs about $209 with a fully activated Windows 10 licence and has 64G eMMC memory, a 1.44 GHz CPU and 4GB of RAM. The cheaper version with 2GB of RAM and 32GB eMMC memory only costs $119 USD. Of interest is that the LattePanda also comes with an Arduino co-processor for various GPIO projects, which could be useful for switching in and out various radio blocks like filters and LNAs.
In his video Marty shows that the SDRAngel software run the LimeSDR smoothly on the LattePanda, and he demonstrates receiving the 30M band. He writes:
Ladies and Gentlemen may I present to you: The LimeSDR operating on receive on the 30m Shortwave Band using SDRAngel running on a Windows 10, 64-bit, 4G (RAM) 64G (FLASH) operating at 1.8 GHz on a LattePanda – – THE SMALLEST WINDOWS 10 PC ON EARTH..! No kidding, this makes my MSI ‘hockey puck’ PC look monstrous…The LattePanda is about the same size as my LimeSDR and a VERY POWERFUL little PC, too…I’m INCREDIBLY impressed with this tiny PC…This Single Board Computer also has an integrated Arduino processor such that all the bandswitching and other functions required to make a Software Defined Transceiver will be very trivial to add-in…The ‘proof of concept’ is complete – – this shows that it CAN BE DONE to make the LimeSDR into a compact, wideband Software Defined Transceiver that can be run on a car battery if needed…Watch the video and see for yourself…CHEERS..!
In a second newer video he demonstrates the system running on a 7″ LCD touchscreen. He writes:
Here’s a follow-up YouTube video I did when I laced-up the LattePanda to a 7″ LCD and the companion Capacitive Touchscreen for the LimeSDR. This thing is awesome and very compact – it’s amazing. I’m planning to take those same components and mount them into a walnut case that I’m getting made from furniture-grade wood from Amana. The case will be sloped and will have enough room to put the LattePanda, LimeSDR, USB 3.0 hub, and *maybe* the PA – but I have to think that the PA will be outboard along with the Bandpass Filter Card assembly, too. I am planning to make a preselector/receive preamplifier for the LimeSDR that will reside in the case, too. The LattePanda not only has the Intel CherryTrail processor there for Windows, but it also has an integrated Arduino processor on the board along with the Arduino development software and the GPIO on the LattePanda to drive the BPF, PA, T/R switching, and the receive preamplifier/preselector/filter. No kidding – when this is all done this thing is going to be unstoppable. SDRAngel is open source so adding the communications for band switching will not be hard to do between Edouiard’s source in Win32 and to the Arduino through DLL calls. I’m even giving some serious thought about how LimeSDR-Mini will be included as an alternative with an even smaller footprint for this.
Looks like the LimeSDR is slowly starting to all come together as a fully usable system for ham radio thanks to the efforts of people like Marty. Remember that Lime are currently crowdfunding for their latest LimeSDR Mini product, which is a cheaper $139 version of their LimeSDR. Currently almost $85k of the required $100k has already been raised, with still 40 days to go.
Back in June 2016 the first LimeSDR crowdfunding campaign completed raising over a million dollars in pre-orders at a cost of $249 – $299 per LimeSDR unit. THe LimeSDR is a RX and TX capable SDR with a frequency range of 100 kHz – 3.8 GHz, bandwidth of up to 61.44 MHz, 12-bit ADC and 2×2 RX/TX channels.
Currently the LimeSDR Mini is being sold on the crowdfunding site CrowdSupply for $139, but the first 500 early bird backer can get the lower price of $99. Accessories such as an acrylic enclosure and set of whip antennas are also available for $40. Crowdfunding is due to end on October 30 and the units are expected to ship on Dec 31, 2017. Note that in the last few minutes that it took to write this article the number of pledges went up by 5 (started at 41), so we’d suggest being quick to claim the early bird if you are interested.
The LimeSDR Mini looks like it could compete favorably with the PlutoSDR, which is another recently released $99 SDR with TX capabilities. Both the PlutoSDR and LimeSDR Mini are 12-bit devices, but the LimeSDR Mini has the larger 30 MHz bandwidth available, and can tune lower. In contrast the PlutoSDR only has a stable bandwidth of about 4 MHz, although it can be pushed higher with dropped samples. The PlutoSDR also has a tuning range (with hack) of 70 MHz – 6 GHz, vs the 10 MHz – 3.5 GHz of the LimeSDR Mini. Another plus of the LimeSDR products is that they are fully open source.
These are exciting times for SDR enthusiasts with cheap TX capable radios now starting to proliferate on the market!
Over on the LimeSDR facebook group Marty Wittrock (KN0CK) has been experimenting with his LimeSDR and SDRAngel. SDRAngel is a general purpose SDR program similar to SDR#/HDSDR/SDR-Console etc, but with the key difference that it is designed to incorporate TX features as well. SDRAngel has releases available for Linux and Windows.
Marty writes that in early August SDRAngel programmer Edouard (F4EXB) resolved most of the issues with LimeSDR compatibility and now TX and RX in SDRAngel with the LimeSDR works great.
SDRANGEL/LIMESDR WINDOWS UPDATE – WORKING!: …For the first time in 18 months the LimeSDR has a working Windows transmit and receive application..! Check out the video for more, but for those that don’t use Linux, you can now experience full transmit and receive using the Win32 SDRAngel version 3.5.5 and Zadig 2.2 that loads the LimeSDR driver…Just load Zadig first as you normally would to select the LimeSDR (after you’ve initially installed it) and then launch SDRAngel…The application will allow you to operate ANYWHERE from 160m to 70cm using any demodulator and modulator you wish (AM, FM, SSB, CW, and more!). I tested it this evening from 40m to 10m to 2m tonight and it works EXCELLENT..!! Get in while the gettin’ is good – A full-up transceiver app now exists for the LimeSDR and this is just the beginning..! 73 de KN0CK
LIMESDR/SDRANGEL UPDATE: Yours truly the mad scientist, playing with the LimeSDR on HF at 7.0 MHz here within the shack (no external antennas applied) TRANSMITTING NO DELAY ON HF LOWER SIDEBAND USING SDRANGEL AND THE LIMESDR..!! FINALLY, an app that supports receive and transmit for the LimeSDR is available free of charge and WORKS PERFECTLY..!! See it for yourself on the attached video…And I do have the recipe for this since it’s on Linux (Ubuntu 16.04) for now…A Windows 7/10 build IS planned…A RED LETTER DAY FOR THE LIMESDR..!! #LimeSDR #SDRAngel #HF 🙂 !!
Recently Michael DG0OPK wrote in and wanted to share some videos of the LimeSDR in action that he’s uploaded to YouTube. The first video shows LimeSDR running with the SDRangel software and receiving the 950 MHz mobile phone band. SDRangel appears to be GPU accelerated so the waterfall can show a lot of detail very quickly.
The second video shows the LimeSDR transmitting DVB-S/S2 on and ODROID XU4, and the signal being received on a PC using and Airspy, and being watched live with a standard DVB-S2 TV Card. The Odroid XU4 is a single board computer like the Raspberry Pi but much more powerful.
On his channel Michael also has some other LimeSDR videos that you can check out such as testing the LimeSDR with GNURadio on the 23cm band for full duplex DVB-S2, and running the LimeSDR at full speed 60fps, 50 MHz on a i7 PC.
The LimeSDR is a full duplex RX/TX capable SDR with a 100 kHz – 3.8 GHz frequency range, 12-bit ADC and up to 80 MHz of bandwidth. A unit currently a unit currently costs $289 USD on Crowd Supply.