Search results for: Marty Wittrock

LimeRFE: A LimeSDR RF Front End for Ham, Cellular and Wideband Networks

Over on CrowdSupply LimeMicro are currently preparing to crowdfund their next project called 'LimeRFE'. LimeRFE is an RF front end power amplifier with filtering. It is designed to be used in conjunction with a LimeSDR or LimeSDR Mini. The LimeSDR and LimeSDR Mini are 12-bit TX and RX capable SDRs that were crowdfunded in the past. The LimeSDRs appear to be mostly aimed at cellular/industrial/commercial use cases, but there have been efforts (mostly from Marty Wittrock) to make the LimeSDR useful for ham radio.

For ham radio usage the LimeRFE front end module contains band filters for the HF band (1.6 - 30 MHz), the 2m band (144 - 146 MHz), the 70cm band (430 - 440 MHz), the 23cm band (1240 - 1325 MHz), the 13cm band (2300 - 2450 MHz) and the 3300 - 3500 MHz band. They do note that for HF use, additional filtering may still be required. On these bands the power amplifier is capable of boosting the power up to a P1 point of 35 dBm on the lower bands down to 26.5 dBm at 3 GHz.

The LimeRFE is not yet available for CrowdFundng as it is still in the prototype stages, but they note that the board is close to being finalized. You can sign up to be notified of when the board is ready on the Crowd Supply page.

LimeRFE Rendering
LimeRFE Rendering

LimeSDR Mini Unboxing and Initial Review

The LimeSDR Mini has now started shipping out to backers, and we received our unit just last week. The LimeSDR Mini is the smaller version of the full sized LimeSDR which was released early last year in 2017. The standard LimeSDR has a frequency range of 100 kHz – 3.8 GHz, bandwidth of up to 61.44 MHz, 12-bit ADC and 2 x 2 RX/TX channels. In comparison the new LimeSDR mini has a 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 x 1 TX/RX channels. The price is however much less coming in at US$139 for the mini and US$299 for the standard LimeSDR.
In this post we’ll give a brief unboxing and review of the LimeSDR Mini. If you’re interested take a look at our previous unboxing and initial review of the standard LimeSDR as well.


The LimeSDR Mini came in a small black box inside an anti-static bag. No accessories like antennas are included in the package. The PCB comes without any enclosure, but an enclosure can be ordered as an additional extra. The size of the PCB is similar to an RTL-SDR, but a little wider. The RF sensitive components are covered with a shielding can. Removing the can reveals the main Lime System RF chip, the LMS7002M, as well as several RF transformer matching circuits.
One end of the PCB has a standard USB-A connector, whilst the other end has two SMA ports, one for receiving and the other for transmitting.
The LimeSDR Mini
The LimeSDR Mini


Continue reading

Testing out SDRAngel with an RTL-SDR

SDRAngel is a general purpose SDR program similar to other programs like SDR#, HDSDR and SDR-Console. It is compatible with Windows and Linux systems. However, SDRAngel has certain features that make it a good program to have in your SDR software arsenal.

One good feature is that if you have a TX capable SDR like a HackRF, PlutoSDR, BladeRF or LimeSDR then SDRAngel can also be used for TXing. Marty Wittrock has done a lot of previous work figuring out how to TX with LimeSDR and SDRAngel.

If you're only interested in RXing then SDRAngel also has some convenient features such as a built in DSD decoder which can be used to easily decode DMR/MOTOTRBO, dPMR, D-STAR and Yaesu System Fusion (YSF). The decoder is based on the DSDcc library which is a complete rewrite of the original open source DSD software.  It is not quite as developed and feature rich as DSD+, but still does the job decently. SDRAngel also has LoRa and analogue TV (ATV) decoders built in as well, although the ATV decoder kept crashing the software for us.

SDRAngel also supports multiple VFO's on the same bandwidth, has built in decimation, a nice phosphor effect RF spectrum display and a frequency manager. There is also the ability to run multiple SDRs in the same software instance at the same time.

We gave SDRAngel a try on Windows and were able to easily get it up and running with an RTL-SDR. Regular WFM, FM, AM, SSB etc modes all work fine and so does the DSD decoder which we tested on a DMR signal. Getting it to decode was extremely simple, just add a DSD Demodulator channel, then click on the signal and you should be instantly decoding. It is probably the easiest way to get started on decoding a non-trunking digital voice channel, but for trunking channels and P25 signals you should probably still use Unitrunker and DSD+ or SDRTrunk.

SDRAngel Screenshot
SDRAngel Screenshot

Below is a brief tutorial on getting up an running with SDRAngel on Windows with an RTL-SDR:

  1. Download the latest version of SDRAngel from the releases section of the GitHub. Only a build for Windows x64 is available and this has the filename sdrangel64_v3.8.4.7z (version number may change in the future). Linux .deb files are also available for various Ubuntu versions.
  2. Using 7zip, extract the 7z file to a folder on your PC.
  3. Plug in your RTL-SDR dongle, and run sdrangel.exe. We assume zadig has already been previously run to install the RTL-SDR drivers.
  4. On the left under 'sampling devices control' click on the small hand icon. A drop down box will pop up, and from here you should be able to select the RTL-SDR. Press ok.
  5. Now you can click the green play button on the top left to start the SDR.
  6. By default the display bandwidth is zoomed in very closely with x16 decimation and a sample rate of 1 MSPS. So in the top left box change "Dec" to 1, and increase the sample rate to 2 or 2.4 MSPS if you like.
  7. We suggest also clicking on the 'DC' button in the top left to remove the DC spike.
  8. Now you can tune around just like in other software by using the frequency numbers in the top left.
  9. If you want a spectrum analyzer display, go to the bottom left box, and click on the blue spectrum icon.
  10. Unlike most other software you need to add a demodulator first before you can click on a signal and listen to it. The list of available demodulators can be found in the second box on the left, just below the hand icon which you used to add the RTL-SDR.
  11. Select the correct demodulator for your signal of interest (e.g. WFM, NFM, AM, DSD, LoRa etc...), and then click the "+" icon. This will add the demodulator to the right of the SDRAngel window. You may want to drag the right window a little large if you cannot see all of the demodulator option as well.
  12. Now you can click on the signal in the spectrum window to move the VFO and begin demodulating the signal. You can explore the demodulator options on the right.
  13. Multiple demodulators can be added if desired, just repeat steps 8 - 10. If you add more than one demodulator, the VFO's will need to be dragged.
  14. If you're having trouble getting a digital voice signal with DSD to be recognized, try zooming in with the decimation feature or reducing the sample rate. It doesn't seem to work too well with higher bandwidths.

LimeSDR Transmitting on the LattePanda

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.

LimeSDR, LattePanda, and SDRAngel Transmitting on 40m LSB Voice

LimeSDR and SDRAngel Running on a LattePanda

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..!

LimeSDR With LattePanda Win10 64-bit

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.

LimeSDR and LattePanda Win10, 64-bit running SDRAngel with 7" LCD/Touchscreen

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.

LimeSDR Transmitting Voice and Data with SDRAngel

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

Posted by Marty Wittrock on Tuesday, 15 August 2017

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 🙂 !!

Posted by Marty Wittrock on Saturday, 12 August 2017

Two Videos Showing the LimeSDR on HF in SDR-Console V3

The LimeSDR is a RX/TX capable SDR with a 100 kHz – 3.8 GHz frequency range, 12-bit ADC and 61.44 MHz bandwidth. It costs $299 USD and we think it is going to be an excellent next generation upgrade to SDR’s with similar price and functionality like the HackRF and bladeRF. Back in August we posted how they had added HF functionality to their drivers, and posted some videos from LimeSDR beta tester Marty Wittrock who had gotten HF working well  in GQRX.

Now that SDR-Console has added support for the LimeSDR and HF reception, Marty has uploaded two new videos showing it in action. The first video shows some SSB reception on 40M and the second shows some CW reception on 20M. Marty runs SDR-Console on a MSI Core i5 Cube PC. Marty also writes:

Even with the ‘older’ LimeSDRs that I have that don’t have the proposed modified matching networks on them the performance at 20m and 40m was actually REALLY good for voice and CW. Obviously if the band conditions for 15m and 10m were better the days that I tested the LimeSDR it would have been even better since ‘as-designed’ matching networks seem to do better at 30 MHz and up. Checking the performance at 162.475 MHz (my local Cedar Rapids, Iowa NOAA Weather Station) the performance is excellent on a VHF antenna.

The LimeSDR on 40m Phone using SDRConsole V3.0
LimeSDR Operating on the HF 20m Band with SDRConsole V3.0


The LimeSDR can now tune to HF Frequencies

Back in June the LimeSDR completed its $500,000 crowd funding goal. The units are still in production and have not yet shipped, but the software is currently being worked on heavily. In a recent update they have enabled HF reception on the LimeSDR hardware. LimeSDR beta tester Marty Wittrock wrote in to let us know his review of the new update:

Another major step forward for the LimeSDR yesterday…

As a part of the continuing development of the PPAs for Ubuntu and other distros, the LimeSDR is now supported for native HF tuning – – no transverter required. Receive has been functionally tested from 7.0 MHz to 56 MHz and even with the matching networks as they are in the LimeSDR I have (which is not what will be delivered in November – the LimeSDRs the backers will receive in November will have modified matching networks to be more broadband and perform better than what I have right now) the receive quality was very good with my applied HF station antenna (ground mounted vertical for 80m – 6m). I shot two videos yesterday of the LimeSDR operating on the 20m band – one with USB voice and one with CW/RTTY on the contest weekend for RTTY (REAL active). I ran this completely from a USB 3.0 Flash Drive plugged into a Dell 3020 and booted from that Flash Drive to operate the LimeSDR. The Flash Drive is loaded with Ubuntu Xenial (16.04), all the applied support files (SoapySDR, GNURadio, OsmoSDR. etc) and the application GQRX to tune and demodulate the LimeSDR. The setup worked VERY well and the results can be viewed with the two videos provided here:

20m Phone Using the LimeSDR in Native HF Tuning Mode Receive
20m CW and RTTY Using the LimeSDR in Native HF Tuning Mode Receive

Again, I was impressed with the quality of the direct, native, HF tuning of the recent updates to LimeSuite. Having this functionality in LimeSuite finalizes for receive, but I still need to check out the transmit. It’s my hope that Simon Brown’s SDR Console V3.0 will update with the new HF tuning improvements such that I can use his app on Windows to do a full checkout in receive/transmit with the LimeSDR and hopefully apply it to the WSPR app to have the LimeSDR operate HF digital modes on the HF band and Amateur Radio frequencies to have the first true LimeSDR operation benchmark.

I fully intend to have Flash Drive images available for download once I put the final touches on the Flash Drive I have. This will allow all Hams that want an instant solution for booting Ubuntu and running GQRX for receive to use their LimeSDRs right out of the chute without having to install ANYTHING provided that they have a PC that is decently fast (3.0 GHz, 8GB RAM) and has USB 3.0 ports on the PC. I’m looking for a reliable means to read/write the Flash Image and then take the image and ‘burn’ other USB 3.0 Flash Drives with the image. Once I have that reliably working, I’ll post the image and the Flash Drive app so ANYONE can make their own from a blank 32GB to 128GB Flash Drive.

More to follow on the HF transmit as I have those apps and check that out – – Stay tuned..!

The LimeSDR is a RX/TX capable SDR with a 100 kHz – 3.8 GHz frequency range, 12-bit ADC and 61.44 MHz bandwidth. It costs $299 USD.