Tagged: gqrx

Talks from the AMSAT-UK RSGB 2017 Convention

The Radio Society of Great Britain (RSGB) and AMSAT-UK recently presented a number of talks at their latest convention held in October of this year. Some of the talks are SDR related and are interesting for those interested in satellite reception. A couple of interesting SDR related talks are presented below, and the rest of the talks can be accessed on their YouTube page.

Software defined radio for the satellite geek - Alex Csete OZ9AEC

In this talk Alex Csete (Oz9AEC) who is the programmer behind the popular GQRX software that is often used with RTL-SDRs discusses his latest work and some of his experiences with writing software for SDRs.

Going to space the libre way - Pierros Papadeas, Libre Space Foundation

In this talk Pierros Papadeas who is the founder of the Libre Space Foundation discusses their SatNOGS project. SatNOGS is a project that uses RTL-SDRs in custom 3D printed home made satellite tracking ground stations. It aims to enable easy access to live satellite data online by significantly increasing ground station coverage.

ADALM-PLUTO SDR Hack: Tune 70 MHz to 6 GHz and GQRX Install

Yesterday we posted an unboxing and a few tests with the PlutoSDR. On that post user rlwsdr commented and informed us that’s it’s actually possible to do a quick hack that changes the frequency range and bandwidth from 325 – 3800 MHz and 20 MHz up to 70 MHz to 6000 MHz and 56 MHz bandwidth. All that is needed to perform this hack is setting a device string on the PlutoSDR via a USB serial connection. This hack has been confirmed by Alex Csete and others on Twitter and ourselves. It works for both RX and TX.

Alexander Csete (programmer of GQRX) also posted instructions in a comment on our last post that explained how to get GQRX running with the PlutoSDR. 

Also in the last post we mentioned that all distributors were out of stock, but a few hours after that post went out Digikey restocked and they now have (at the time of this post) 184 units left at the $99 USD price.

Frequency and Bandwidth Hack

Thanks to ‘rlwsdr’ and Alexandru Csete for bringing attention to this hack.

It seems that the current shipping version of the PlutoSDR uses the AD9363 chip which is restricted to a frequency range of 325 – 3800 MHz and bandwidth of 20 MHz. However, the higher end AD9364 chip which can support 70 MHz to 6000 MHz and 56 MHz of bandwidth is supposedly nearly identical to the AD9363 chip. The PlutoSDR can be tricked into seeing a AD9364 chip simply by changing a device string on the unit, but it’s not guaranteed to give the full tuning range and bandwidth for every single unit. It’s possible that the AD9363 chips are actually AD9364 chips that failed performance QC checks and have just been rebranded as a lower end model, or that a cheaper silicon process is used with the lower end chip.

The instructions for performing this hack are actually detailed by the official Analog.com PlutoSDR wiki on the customization page. Just search for the heading “Updating to the AD9364”. The instructions state that this is only for older PlutoSDR units which actually came with the AD9364 chip, but it seems to work with the newer PlutoSDR units that have the AD9363 chips as well.

Simply plug the PlutoSDR in, and connect to it via a serial connection. On Windows you can use a program like PuTTY for this purpose. First search in device manager for the COM port assigned to your PlutoSDR, and then input this into PuTTY leaving the speed at 9600. You can then log in and set the environment variables using the lines provided in the wiki. Now in GNU Radio, GQRX etc you should be able to tune down to 70 MHz and up to 6 GHz and set the bandwidth to 56 MHz.

PlutoSDR Upgrade instructions
PlutoSDR Upgrade instructions

The images below show the PlutoSDR serial connection screen and the commands you need to type, the PlutoSDR tuning down to broadcast FM frequencies at 100 MHz, and a TX test at 70.1 MHz. It was found that the strength of the TX is a bit lower outside the official range, but can be increased by turning off the attenuation setting.

Serial_upgrade_PuTTY
pluto_upgrade_fm
tx_pluto_70mhz

Setting up the GQRX Experimental Branch for the PlutoSDR

First set up GNU Radio and gr-iio using the instructions from this Reddit thread.

Now install gr-osmosdr-gqrx with the iiodev branch.

git clone https://github.com/csete/gr-osmosdr-gqrx
cd gr-osmosdr-gqrx/
git checkout plutosdr
mkdir build
cd build/
cmake ../
make
sudo make install
sudo ldconfig

Install the GQRX prerequisites

sudo apt-get install git build-essential cmake qtbase5-dev qt5-default qtscript5-dev libssl-dev qttools5-dev qttools5-dev-tools qtmultimedia5-dev libqt5svg5-dev libqt5webkit5-dev libsdl2-dev libasound2 libxmu-dev libxi-dev freeglut3-dev libasound2-dev libjack-jackd2-dev libxrandr-dev libqt5xmlpatterns5-dev libqt5xmlpatterns5 libqt5xmlpatterns5-private-dev pulseaudio

Install GQRX

git clone https://github.com/csete/gqrx.git gqrx.git
cd gqrx.git
mkdir build
cd build
cmake ..
make
sudo make install

Now GQRX should be ready to use the PlutoSDR. In the GQRX confiuguration screen select the device as Other or PlutoSDR and set the device string as “plutosdr=0”. Then you can set your sample rate and RF bandwidth, decimation etc. If you’ve done the frequency range hack then remember to select “No limits” in GQRX so that you can actually tune down further.

Note that in VMWare Lubuntu we were only able to get stable audio from the PlutoSDR and GQRX at a maximum of 3 MHz. Anywhere between 3 – 60 MHz bandwidth the PlutoSDR and GQRX spectrum and waterfall runs smoothly, but the audio is crackly. Might be a VMWare problem, or maybe something that can be fixed in later GQRX releases.

We also tested the PlutoSDR together with the SpyVerter upconverter for HF reception. It seemed to work well.

The images below show the PlutoSDR working in GQRX. The images of the 2.4 GHz and 1.8 GHz bands show that there is little to no attenuation at the edges of the 60 MHz bandwidth, so the upgrade from 20 MHz to 60 MHz is working well.

900 MHz GSM Band

900 MHz GSM Band

Broadcast FM

Broadcast FM

1800 MHz Cellular

1800 MHz Cellular

2.4 GHz WiFi

2.4 GHz WiFi

PlutoSDR + SpyVerter Broadcast AM

PlutoSDR + SpyVerter Broadcast AM

Conclusion

So with this hack the PlutoSDR is a much nicer unit that really makes an interesting and affordable choice for those wanting to upgrade from the RTL-SDR. Combined with a SpyVerter upconverter the unit should also be able to receive HF signals quite easily, so this gives a total cost of $148 for a DC to 6 GHz receiving system with TX capability, 12-bit ADC resolution and up to 56 MHz of bandwidth.

Of course we still need to confirm what the performance of the unit is like, especially in the frequency ranges opened up by the hacks and in regards to strong signal handling. We will test those in the coming weeks. If it handles those well and other software developers support it in their software then despite the unit being advertised as a learning module for students, it might become one of the best and most affordable general purpose SDRs available.

Talks from the AMSAT-UK RSGB 2017 Convention

The Radio Society of Great Britain (RSGB) and AMSAT-UK recently presented a number of talks at their latest convention held in October of this year. Some of the talks are SDR related and are interesting for those interested in satellite reception. A couple of interesting SDR related talks are presented below, and the rest of the talks can be accessed on their YouTube page.

Software defined radio for the satellite geek - Alex Csete OZ9AEC

In this talk Alex Csete (Oz9AEC) who is the programmer behind the popular GQRX software that is often used with RTL-SDRs discusses his latest work and some of his experiences with writing software for SDRs.

Going to space the libre way - Pierros Papadeas, Libre Space Foundation

In this talk Pierros Papadeas who is the founder of the Libre Space Foundation discusses their SatNOGS project. SatNOGS is a project that uses RTL-SDRs in custom 3D printed home made satellite tracking ground stations. It aims to enable easy access to live satellite data online by significantly increasing ground station coverage.

ADALM-PLUTO SDR Hack: Tune 70 MHz to 6 GHz and GQRX Install

Yesterday we posted an unboxing and a few tests with the PlutoSDR. On that post user rlwsdr commented and informed us that’s it’s actually possible to do a quick hack that changes the frequency range and bandwidth from 325 – 3800 MHz and 20 MHz up to 70 MHz to 6000 MHz and 56 MHz bandwidth. All that is needed to perform this hack is setting a device string on the PlutoSDR via a USB serial connection. This hack has been confirmed by Alex Csete and others on Twitter and ourselves. It works for both RX and TX.

Alexander Csete (programmer of GQRX) also posted instructions in a comment on our last post that explained how to get GQRX running with the PlutoSDR. 

Also in the last post we mentioned that all distributors were out of stock, but a few hours after that post went out Digikey restocked and they now have (at the time of this post) 184 units left at the $99 USD price.

Frequency and Bandwidth Hack

Thanks to ‘rlwsdr’ and Alexandru Csete for bringing attention to this hack.

It seems that the current shipping version of the PlutoSDR uses the AD9363 chip which is restricted to a frequency range of 325 – 3800 MHz and bandwidth of 20 MHz. However, the higher end AD9364 chip which can support 70 MHz to 6000 MHz and 56 MHz of bandwidth is supposedly nearly identical to the AD9363 chip. The PlutoSDR can be tricked into seeing a AD9364 chip simply by changing a device string on the unit, but it’s not guaranteed to give the full tuning range and bandwidth for every single unit. It’s possible that the AD9363 chips are actually AD9364 chips that failed performance QC checks and have just been rebranded as a lower end model, or that a cheaper silicon process is used with the lower end chip.

The instructions for performing this hack are actually detailed by the official Analog.com PlutoSDR wiki on the customization page. Just search for the heading “Updating to the AD9364”. The instructions state that this is only for older PlutoSDR units which actually came with the AD9364 chip, but it seems to work with the newer PlutoSDR units that have the AD9363 chips as well.

Simply plug the PlutoSDR in, and connect to it via a serial connection. On Windows you can use a program like PuTTY for this purpose. First search in device manager for the COM port assigned to your PlutoSDR, and then input this into PuTTY leaving the speed at 9600. You can then log in and set the environment variables using the lines provided in the wiki. Now in GNU Radio, GQRX etc you should be able to tune down to 70 MHz and up to 6 GHz and set the bandwidth to 56 MHz.

PlutoSDR Upgrade instructions
PlutoSDR Upgrade instructions

The images below show the PlutoSDR serial connection screen and the commands you need to type, the PlutoSDR tuning down to broadcast FM frequencies at 100 MHz, and a TX test at 70.1 MHz. It was found that the strength of the TX is a bit lower outside the official range, but can be increased by turning off the attenuation setting.

Serial_upgrade_PuTTY
pluto_upgrade_fm
tx_pluto_70mhz

Setting up the GQRX Experimental Branch for the PlutoSDR

First set up GNU Radio and gr-iio using the instructions from this Reddit thread.

Now install gr-osmosdr-gqrx with the iiodev branch.

git clone https://github.com/csete/gr-osmosdr-gqrx
cd gr-osmosdr-gqrx/
git checkout plutosdr
mkdir build
cd build/
cmake ../
make
sudo make install
sudo ldconfig

Install the GQRX prerequisites

sudo apt-get install git build-essential cmake qtbase5-dev qt5-default qtscript5-dev libssl-dev qttools5-dev qttools5-dev-tools qtmultimedia5-dev libqt5svg5-dev libqt5webkit5-dev libsdl2-dev libasound2 libxmu-dev libxi-dev freeglut3-dev libasound2-dev libjack-jackd2-dev libxrandr-dev libqt5xmlpatterns5-dev libqt5xmlpatterns5 libqt5xmlpatterns5-private-dev pulseaudio

Install GQRX

git clone https://github.com/csete/gqrx.git gqrx.git
cd gqrx.git
mkdir build
cd build
cmake ..
make
sudo make install

Now GQRX should be ready to use the PlutoSDR. In the GQRX confiuguration screen select the device as Other or PlutoSDR and set the device string as “plutosdr=0”. Then you can set your sample rate and RF bandwidth, decimation etc. If you’ve done the frequency range hack then remember to select “No limits” in GQRX so that you can actually tune down further.

Note that in VMWare Lubuntu we were only able to get stable audio from the PlutoSDR and GQRX at a maximum of 3 MHz. Anywhere between 3 – 60 MHz bandwidth the PlutoSDR and GQRX spectrum and waterfall runs smoothly, but the audio is crackly. Might be a VMWare problem, or maybe something that can be fixed in later GQRX releases.

We also tested the PlutoSDR together with the SpyVerter upconverter for HF reception. It seemed to work well.

The images below show the PlutoSDR working in GQRX. The images of the 2.4 GHz and 1.8 GHz bands show that there is little to no attenuation at the edges of the 60 MHz bandwidth, so the upgrade from 20 MHz to 60 MHz is working well.

900 MHz GSM Band

900 MHz GSM Band

Broadcast FM

Broadcast FM

1800 MHz Cellular

1800 MHz Cellular

2.4 GHz WiFi

2.4 GHz WiFi

PlutoSDR + SpyVerter Broadcast AM

PlutoSDR + SpyVerter Broadcast AM

Conclusion

So with this hack the PlutoSDR is a much nicer unit that really makes an interesting and affordable choice for those wanting to upgrade from the RTL-SDR. Combined with a SpyVerter upconverter the unit should also be able to receive HF signals quite easily, so this gives a total cost of $148 for a DC to 6 GHz receiving system with TX capability, 12-bit ADC resolution and up to 56 MHz of bandwidth.

Of course we still need to confirm what the performance of the unit is like, especially in the frequency ranges opened up by the hacks and in regards to strong signal handling. We will test those in the coming weeks. If it handles those well and other software developers support it in their software then despite the unit being advertised as a learning module for students, it might become one of the best and most affordable general purpose SDRs available.

Video Tutorial: Installing GQRX and RTL-SDR on a Raspberry Pi

Over on his YouTube channel AVT Marketing has uploaded a new beginner friendly video that shows how to easily install and use GQRX on a Raspberry Pi single board Linux computer. GQRX is a Linux based general purpose SDR receiver program which is compatible with the RTL-SDR. The Raspberry Pi 3 has enough processing power run this software easily with the RTL-SDR.

The tutorial is a 2-part series, with the first video showing how to install the software from scratch. AVT shows every necessary step including installing git, cmake, build-essential, getting and installing the drivers from the Osmocom github and installing libusb. For someone very new to Linux this tutorial is a simple step by step start. The second video goes on to show how to actually use GQRX on the Raspberry Pi.

Version 2.6 of GQRX Released

Version 2.6 of the popular SDR program GQRX has just been released (changelog). GQRX is a general signal browsing program similar to programs like SDR#, HDSDR and SDR-Console. However GQRX is designed to run on Linux, MacOS and Raspberry Pi 2 & 3. Note that v2.6 is still a work in progress for MacOS. Apart from the new features and bug fixes, one of the major improvements appears to be reduced CPU usage, meaning that it should run better on older PCs. The changelog is pasted below:

New features

  • 1-2-5 scaling on FFT axis.
  • Audio waterfall.
  • Remember AGC settings between sessions.
  • Right-click on FFT resets frequency zoom.
  • Separate dB ranges for pandapter and waterfall.
  • Raw I/Q mode.
  • Portaudio support.
  • Command line option to set Qt style (fusion, windows, …)
  • Binary packages for Raspberry Pi 2 and 3 (see below)

Bugs fixed

  • Stuttering audio with Pulseaudio backend.
  • Use system font on FFT plot (too small font on high res displays).
  • Broken FUNcube Dongle Pro+ support on Mac OS X 10.11.4.
  • Correct display of negative offsets between -1 and 0 kHz.
  • Reset frequency digits below the one that is being changed.
  • LNB LO could not be set from I/O configuration dialog.
  • Update squelch level when switching between demodulators.
  • Set correct filter range when loading bookmark.
  • White area on waterfall.
  • RFSpace Cloud-IQ support on Mac OS X, RPI binaries and in PPA.

Miscellaneous improvements

  • Input decimator performance.
  • SDRPlay integration through SoapySDR.
  • Only probe for devices when the program is started.
  • Allow user to enter ALSA device name.
  • Set default audio FFT range to -70…0 dB.
  • Restore audio FFT dB scaling between sessions.

GQRX

Installing GQRX on OSX El Capitan

OSX users often don’t have much choice when it comes to general purpose SDR receiver software for the RTL-SDR or other SDR’s. However, one program that works well on Macs is GQRX. Installing GQRX on OSX can sometimes be difficult as the most common installation method involves using Macports, which won’t always work depending on the version of OSX you are using.

Recently, OSX and RTL-SDR user smittix wrote in to use to let us know that there is now a very easy way for El Capitan OSX users to install GQRX. Basically the GQRX team have now released a DMG file which can be downloaded and installed just like most other easy to use applications. Using the DMG file smittix was able to get up and running within 5 minutes.

GQRX running on El Capitan OSX
GQRX running on El Capitan OSX

Combining the bandwidth of multiple RTL-SDRs: Now working in GQRX!

A few days ago we posted how Oliver, an RTL-SDR experimenter, managed to (incoherently) combine the bandwidths of two RTL-SDR dongles to create a 4.4 MHz FFT display in GNU Radio. Now Oliver has taken this idea further and produced an updated version of his GNU Radio program

Oliver’s GNU Radio program is now capable of combining four RTL-SDR dongles and is now also capable of piping the output via a FIFO to GQRX. With four RTL-SDR dongles you can get a total bandwidth of 8.4 MHz. He also writes that it is even possible to listen to analog signals that are in overlapping areas.

Four RTL-SDRs producing a total of 8.4 MHz of bandwidth in GQRX.
Four RTL-SDRs producing a total of 8.4 MHz of bandwidth in GQRX.

Installing GQRX on Mac OSX

Mac OSX users can have a hard time with the RTL-SDR as there are not many software packages available for it. One software package that is known to work well on OSX is GQRX, which is a general multi mode receiver GUI that is similar to the Windows software SDR#. Over on smittix’s blog, the author has created a post showing how to install the latest version of GQRX on OSX. The installation involves using Macports, a system that allows some open source programs like GQRX to be automatically compiled and installed on OSX.

GQRX running on a Mac Computer
GQRX running on a OSX Computer

RTL-SDR with GQRX Running on an Odroid C1 at 1 MSPS and Max FFT

Over on YouTube user neutron2025 has uploaded some videos showing GQRX running on an Odroid C1. The Odroid C1 is a low cost ($35 USD) mini computer with an Arm Cortex A5 quad core CPU and 1 GB RAM which runs Ubuntu 14.04 or Android KitKat. It is a much more powerful competitor to the Raspberry Pi which also goes for around the same price.

Despite its low cost, the video by neutron2025 shows that the Odroid C1 has enough processing power to run the relatively CPU intensive GQRX SDR software with the RTL-SDR at a 1 MSPS sampling rate and maximum FFT resolution.

To install GQRX, GNU Radio also needs to be installed. Installation of GNU Radio is a lengthy process containing many writes to the file system. The amount of writes that occur could destroy a SDCard. To get around this neutron2025 connected an external hard drive and used that as a swap file while installing GNU Radio. His installation notes can be found on pastebin. He writes that installation took around 8 hours.