Category: PlutoSDR

Transmitting DVB-S with a PlutoSDR and Receiving it with an RTL-SDR

Over on YouTube Christopher Bridges has uploaded a video showing him using a PlutoSDR and a GNU Radio program to transmit a DVB-S signal, which is then received with an RTL-SDR. DVB-S is a digital video broadcasting standard designed for satellite transmissions and digital amateur television video (DATV) also uses DVB-S in the 1.2 GHz amateur band. In this example the PlutoSDR transmits at 1.28 GHz.

Chris uses the rtl_sdr command line software to receive the raw IQ data at 1 MSPS, and then uses the leandvb software to decode the raw IQ file directly into a video file.

If you’re interested in TXing DVB-S/DATV but don’t have a transmit capable SDR, then we note that even a Raspberry Pi just by itself can be used to transmit it with rpidatv.

PlutoSDR Quickstart Guide

This guide is intended to get you set up with your PlutoSDR quickly and easily on either Linux or Windows. We also show how to apply a simple software ‘hack’ to your PlutoSDR to extend its frequency range to about 70 MHz to 6000 MHz and bandwidth to 56 MHz.

Applying the Frequency + Bandwidth Expansion Hack

Note that the Windows SDR# plugin requires this hack to be performed first, which is why we put this hack at the top. This hack tricks the PlutoSDR firmware into thinking is has the AD9364 chip. As the AD9363 and AD9364 chips are very similar this works. Note that you do this at your own risk, but we feel that the risk is very low.

This tutorial is for Windows and PuTTY, but could be applied to any OS and terminal software

  1. If you don’t have it already, download the terminal emulator software PuTTY from putty.org.
  2. Plug in your PlutoSDR on the USB port.
  3. Open Windows Device Manager, and expand the Ports (COM & LPT) entry. Take a note of what COM port the PlutoSDR Serial Console is using. In the screenshot ours is using COM6. Close device manager after.
     
     
  4. Open PuTTY and select the ‘serial’ button.
  5. Under ‘Serial line’ type in the COM port the PlutoSDR is using. In our case we type COM6.
     
     
  6. Press Open and you should be greeted with a login screen.
  7. Login with the credentials username: root, password: analog.

Now follow the instructions in the following screenshot image, typing in the three commands as they appear.

PlutoSDR Upgrade instructions

An example of the commands being entered in PuTTY

After doing a reset your PlutoSDR should now be upgraded to the full frequency range and bandwidth.

Windows PlutoSDR SDR# Setup

  1. Download the Windows Drivers from here. Choose the latest version of the PlutoSDR-M2k-USB-Drivers.exe download.
      
  2. Run the installer and complete the installation by clicking through the prompts.
     
  3. Plug in your PlutoSDR. Windows should automatically recognize the PlutoSDR and a folder containing the PlutoSDR config file may pop up. PlutoSDR creates a USB disk drive, USB network connection and a USB serial port. You can confirm in Windows Device Manager if these interfaces have been added.
     
  4. Download and extract SDR# into a folder of your choice from airspy.com/download. Make sure that you download the x86 version, do NOT download the x64 version.
      
  5. Grab the current release of the SDR# PlutoSDR plugin from here. Download the sdrsharp-plutosdr-x.x.x.zip file.
      
  6. Extract the contents of the PlutoSDR SDR# plugin zip file into your SDR# folder.
      
  7. In the SDR# folder find the “FrontEnds.xml” file. Right click it and go to “Open With” open it with Notepad, or any other text editor of your choosing.
      
  8. Before the </frontendPlugins> closing tag, add the PlutoSDR key <add key=”PlutoSDR” value=”SDRSharp.PlutoSDR.PlutoSDRIO,SDRSharp.PlutoSDR” />, and then save and close Notepad.
     
     
  9. Open SDR# and under the Source pull down box choose PlutoSDR.
      
  10. Open the properties box by clicking on the cog icon which is next to the play button. In the default Connection tab ensure the Device-URI is “ip:192.168.2.1”, and then click on “Connect”.
      
  11. Still in the properties box go to the “Receiver tab”. Choose a sample rate up to or below 4 MSPS. Higher sample rates can be selected if desired, but note that you will have dropped samples (e.g. choppy audio). This is a hardware limitation of the PlutoSDR. (Note that there currently seems to be a bug where if you mouse over the FFT or waterfall parts of SDR# then the PlutoSDR config box will be sent to the background. Move the config box to the very left to avoid this. If it disappears just click the cog icon to get it back. If you can’t move it because you’ve moved it too far to the right, minimize SDR# and frag it back to the left.)
      
  12. Press close the configuration box, and then press the Play button in SDR#. The PlutoSDR should now be running.
     
     
  13. Open the configuration box again to adjust the gain.
     

Linux Instructions (Still Coming)

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Opening a Car and Garage Door With PlutoSDR

Over on his YouTube channel Tysonpower (aka Manuel) has uploaded a video showing how he was able to use his PlutoSDR to perform some simple replay attacks that open his garage and car doors. To do this he records the signal from the wireless keyfobs with the PlutoSDR, and then uses a GNU Radio program to replay that signal again at a later time. From the tests he concludes that the PlutoSDR can be a great cheaper alternative to a HackRF, with the PlutoSDR coming in at $100 vs $300 for the HackRF.

To get around the rolling code security on his car he records the keyfob with the PlutoSDR while it’s out of the wireless range of his car, so that the rolling code will not be invalidated. Then later closer to the car the PlutoSDR is used to replay the car keyfob signal which opens the door.

Note that Tysonpower’s video is narrated in German, but English subtitles are available through the YouTube interface.

ADALM-Pluto 2-tone Test at 144 MHz

Over on his YouTube channel Adam 9A4QV has been testing his ADALM-PLUTO SDR in the 2M ham band at around 144 MHz. In one of his videos he shows a 2-tone test. A 2-tone test is used to determine how well an SDR can handle two strong narrowband signals at once, without causing intermodulation and imaging problems. The two tones in his video occur with real world signals on the 2M band when two amateur radio operators are transmitting strong signals at the same time.

The video shows that the Pluto SDR has some intermodulation problems occurring when the two strong signals transmit at once. No problems are noticed when only one signal transmits.

Problems like this with the PlutoSDR may be expected as it was never designed to be a high performance receiver, but rather a tool for learning and experimentation. But it is still possible to use it as a more general purpose receiver if you are aware of the limitations.

(Almost) Receiving HRPT with the ADALM-PLUTO and a WiFi Grid Antenna

Over on YouTube user Tysonpower has uploaded a video showing how he was (almost) able to receive the HRPT signal from NOAA18 with an ADALM-PLUTO, LNA4ALL and a WiFi grid antenna.

Most readers will be familiar with the low resolution 137 MHz APT weather satellite images transmitted by the NOAA weather satellites. But NOAA 15, 18, 19 and well as Metop-A and Feng Yun satellites also transmit an HRPT (High Resolution Picture Transmission) signal up in the 1.7 GHz region. These HRPT images are much nicer to look at with a high 1.1 km resolution. If you follow @usa_satcom on Twitter you can see some HRPT images that he uploads every now and then.

However HRPT is quite difficult to receive and decode because the bandwidth is about 3 MHz so something with more bandwidth than an RTL-SDR is required. The signal also needs a ~1 meter or larger dish antenna as it is very weak, and you also need a motorized pointing system to track the satellite with the dish as it passes over.

Despite the difficulty in his video Tysonpower showed that he was able to at least receive a weak signal using a non-optimal 2.4 GHz WiFi grid dish antenna, LNA4ALL and his ADALM-PLUTO. The signal is far too weak to actually decode, but it’s still pretty surprising to receive it at all. In the future Tysonpower hopes to be able to improve his system and actually get some image decodes going. Note that the video is in German, but there are English subtitles available.

L-Band and 6GHz Tests with the ADALM-PLUTO SDR

Over on YouTube Adam 9A4QV has uploaded two videos that show his tests with the ADALM-PLUTO SDR on the L-band and up at 6 GHz. In his first video the L-band test shows that the receiver is quite sensitive in this region, managing to receive L-band satellites without any LNA. Although he also tests reception with an LNA4ALL in the receive chain, and this still does improve reception even more.

In the second video Adam confirms that reception is available up to 6 GHz using a PlutoSDR with frequency extension hack enabled.

Some Further Tests with the ADALM-PLUTO SDR

Last week we posted about the unboxing of the ADALM-PLUTO SDR as well as some information about a hack that can be used to increase the tuning and bandwidth range of the SDR. In this post we show some initial tests and first impressions of the the receive performance of the SDR.

We tested the PlutoSDR on a number of frequencies, some in the default tuning range, and some in the frequencies enabled by the hack. In terms of sensitivity not much difference was noticed in the expanded frequencies. Sensitivity overall is decent and seems to be comparable to other SDRs. However, the PlutoSDR does suffer quite heavily from out of band imaging. Although there is a 12-bit ADC being used, filtering is still necessary for many signals. Broadcast FM, DAB, HDTV and GSM are all very problematic and images of these signals can be found all over the spectrum if they are strong. Above about 800 MHz two broadcast FM stations show up in the exact same place at all frequencies, no matter the gain setting.

Imaging is probably expected as the IIP3 spec of the AD9363 RF chip used in the PlutoSDR is not that great at only -18 dBm at max gain. Other SDRs like the Airspy Mini and RSP2 don’t have imaging anywhere as bad as the PlutoSDR as they have naturally high dynamic range in the case of the Airspy and filter banks built-in in the case of the RSP2.

Below are some example screenshots of the imaging we saw from strong signals. We used SDR# with the new PlutoSDR plugin, and set the sampling rate to 3 MSPS. On these screenshots we note that turning down the gain did not help, so these images were present in some way no matter the gain settings. There is probably still some optimization to go in the SDR# plugin, so it’s possible that imaging could be reduced with further work.

DAB Appearing at 79 MHz

DAB Appearing at 79 MHz

GSM at 133 MHz

GSM at 133 MHz

No imaging here (see next slide)

No imaging here (see next slide)

But moved 1 MHz up and there is heavy imaging

But moved 1 MHz up and there is heavy imaging

GSM @ 315 MHz

GSM @ 315 MHz

BCFM Pulsing in at 415 MHz

BCFM Pulsing in at 415 MHz

BCFM interference shows up like this at all frequencies above 800 MHz

BCFM interference shows up like this at all frequencies above 800 MHz

To test sensitivity we recorded audio on a few weak signals that did not have any images present, and we kept the gain at the highest it could go without the noise floor rising or images showing up.

Again we used SDR# with the PlutoSDR plugin, and set the sampling rate to 3 MSPS. We note that anything higher than 4 MSPS causes lost samples and thus jittery audio as this is the hardware limit of the PlutoSDR.

BCFM

This is a weak BCFM station. The PlutoSDR actually seemed to receive it better than the Airspy Mini. The RSP2 could not receive it, and the weak audio heard on the RSP2 is audio from an image.

PlutoSDR

PlutoSDR

Airspy Mini

Airspy Mini

SDRplay RSP2

SDRplay RSP2

161 MHz

This is a voice weather station. Here the PlutoSDR was very comparable to the Airspy Mini and RSP2. Not much sensitivity degradation in the ‘hacked’ expanded frequency range.

PlutoSDR

PlutoSDR

Airspy Mini

Airspy Mini

SDRplay RSP2

SDRplay RSP2

858 MHz

This is a digital trunking signal (there was no stable voice source this high to test with). Sensitivity is about the same as the other SDRs.

PlutoSDR

PlutoSDR

Airspy Mini

Airspy Mini

SDRplay RSP2

SDRplay RSP2

BCAM (Night)

A night time BCAM test. The PlutoSDR was coupled with a SpyVerter. Performance was quite good and on par with the Airspy Mini.

PlutoSDR

PlutoSDR

Airspy Mini

Airspy Mini

SDRplay RSP2

SDRplay RSP2

L-Band

Tested reception with a L-band patch antenna (no external LNA). Tested STD-C reception too. The PlutoSDR worked very well on L-band and had similar performance to the SDRplay. The Airspy is not good at L-band without an LNA and could not receive the STD-C channel by itself.

PlutoSDR

PlutoSDR

PlutoSDR STD-C

PlutoSDR STD-C

Airspy Mini

Airspy Mini

SDRplay RSP2

SDRplay RSP2

SDRplay RSP2 STD-C

SDRplay RSP2 STD-C

Conclusion

It’s clear that the PlutoSDR wasn’t made to be a general purpose high performance SDR, but rather a hackers/experimenters/learning SDR.  Performance in terms of out of band imaging is not great, and for any real listening filters may be required. That said, the performance is overall still not bad and overall still a bit better than an RTL-SDR or HackRF. With filtering the performance could be comparable to something like the Airspy Mini or SDRplay RSP2. Performance on L-band is very good, assuming you can filter or use a directional antenna to attenuate strong blocking signals. It’s also possible that further tweaks to the filter settings of the SDR# PlutoSDR plugin could improve imaging problems.

It’s also a bit disappointing that the maximum sample rate available is only 4 MSPS without drops. So this is the highest rate that you can use if you want to decode a signal, or listen to audio. For wideband waterfalls or spectrum analysis or other applications tolerant to dropped samples it should be possible to go up to the full 61.44 MSPS.

All in all, if you are interested in a low cost wideband SDR that does almost everything including TX, and are not too concerned about strong signals, images and overload, then this is still a great purchase at $99 USD (Digikey out of stock now, available for $149 on the Analog.com store). This SDR should be especially interesting to you if you are an SDR hacker/experimenter/student or are a fan of cheap SDRs/RTL-SDR/HackRF etc. If you are a ham or DXer and want something that just works with your high performance antennas and strong signals then you might look elsewhere.

On Twitter others have come to similar conclusions.

Transmitting DVB-S with a PlutoSDR and Receiving it with an RTL-SDR

Over on YouTube Christopher Bridges has uploaded a video showing him using a PlutoSDR and a GNU Radio program to transmit a DVB-S signal, which is then received with an RTL-SDR. DVB-S is a digital video broadcasting standard designed for satellite transmissions and digital amateur television video (DATV) also uses DVB-S in the 1.2 GHz amateur band. In this example the PlutoSDR transmits at 1.28 GHz.

Chris uses the rtl_sdr command line software to receive the raw IQ data at 1 MSPS, and then uses the leandvb software to decode the raw IQ file directly into a video file.

If you’re interested in TXing DVB-S/DATV but don’t have a transmit capable SDR, then we note that even a Raspberry Pi just by itself can be used to transmit it with rpidatv.

Opening a Car and Garage Door With PlutoSDR

Over on his YouTube channel Tysonpower (aka Manuel) has uploaded a video showing how he was able to use his PlutoSDR to perform some simple replay attacks that open his garage and car doors. To do this he records the signal from the wireless keyfobs with the PlutoSDR, and then uses a GNU Radio program to replay that signal again at a later time. From the tests he concludes that the PlutoSDR can be a great cheaper alternative to a HackRF, with the PlutoSDR coming in at $100 vs $300 for the HackRF.

To get around the rolling code security on his car he records the keyfob with the PlutoSDR while it’s out of the wireless range of his car, so that the rolling code will not be invalidated. Then later closer to the car the PlutoSDR is used to replay the car keyfob signal which opens the door.

Note that Tysonpower’s video is narrated in German, but English subtitles are available through the YouTube interface.

ADALM-Pluto 2-tone Test at 144 MHz

Over on his YouTube channel Adam 9A4QV has been testing his ADALM-PLUTO SDR in the 2M ham band at around 144 MHz. In one of his videos he shows a 2-tone test. A 2-tone test is used to determine how well an SDR can handle two strong narrowband signals at once, without causing intermodulation and imaging problems. The two tones in his video occur with real world signals on the 2M band when two amateur radio operators are transmitting strong signals at the same time.

The video shows that the Pluto SDR has some intermodulation problems occurring when the two strong signals transmit at once. No problems are noticed when only one signal transmits.

Problems like this with the PlutoSDR may be expected as it was never designed to be a high performance receiver, but rather a tool for learning and experimentation. But it is still possible to use it as a more general purpose receiver if you are aware of the limitations.

(Almost) Receiving HRPT with the ADALM-PLUTO and a WiFi Grid Antenna

Over on YouTube user Tysonpower has uploaded a video showing how he was (almost) able to receive the HRPT signal from NOAA18 with an ADALM-PLUTO, LNA4ALL and a WiFi grid antenna.

Most readers will be familiar with the low resolution 137 MHz APT weather satellite images transmitted by the NOAA weather satellites. But NOAA 15, 18, 19 and well as Metop-A and Feng Yun satellites also transmit an HRPT (High Resolution Picture Transmission) signal up in the 1.7 GHz region. These HRPT images are much nicer to look at with a high 1.1 km resolution. If you follow @usa_satcom on Twitter you can see some HRPT images that he uploads every now and then.

However HRPT is quite difficult to receive and decode because the bandwidth is about 3 MHz so something with more bandwidth than an RTL-SDR is required. The signal also needs a ~1 meter or larger dish antenna as it is very weak, and you also need a motorized pointing system to track the satellite with the dish as it passes over.

Despite the difficulty in his video Tysonpower showed that he was able to at least receive a weak signal using a non-optimal 2.4 GHz WiFi grid dish antenna, LNA4ALL and his ADALM-PLUTO. The signal is far too weak to actually decode, but it’s still pretty surprising to receive it at all. In the future Tysonpower hopes to be able to improve his system and actually get some image decodes going. Note that the video is in German, but there are English subtitles available.

L-Band and 6GHz Tests with the ADALM-PLUTO SDR

Over on YouTube Adam 9A4QV has uploaded two videos that show his tests with the ADALM-PLUTO SDR on the L-band and up at 6 GHz. In his first video the L-band test shows that the receiver is quite sensitive in this region, managing to receive L-band satellites without any LNA. Although he also tests reception with an LNA4ALL in the receive chain, and this still does improve reception even more.

In the second video Adam confirms that reception is available up to 6 GHz using a PlutoSDR with frequency extension hack enabled.

Some Further Tests with the ADALM-PLUTO SDR

Last week we posted about the unboxing of the ADALM-PLUTO SDR as well as some information about a hack that can be used to increase the tuning and bandwidth range of the SDR. In this post we show some initial tests and first impressions of the the receive performance of the SDR.

We tested the PlutoSDR on a number of frequencies, some in the default tuning range, and some in the frequencies enabled by the hack. In terms of sensitivity not much difference was noticed in the expanded frequencies. Sensitivity overall is decent and seems to be comparable to other SDRs. However, the PlutoSDR does suffer quite heavily from out of band imaging. Although there is a 12-bit ADC being used, filtering is still necessary for many signals. Broadcast FM, DAB, HDTV and GSM are all very problematic and images of these signals can be found all over the spectrum if they are strong. Above about 800 MHz two broadcast FM stations show up in the exact same place at all frequencies, no matter the gain setting.

Imaging is probably expected as the IIP3 spec of the AD9363 RF chip used in the PlutoSDR is not that great at only -18 dBm at max gain. Other SDRs like the Airspy Mini and RSP2 don’t have imaging anywhere as bad as the PlutoSDR as they have naturally high dynamic range in the case of the Airspy and filter banks built-in in the case of the RSP2.

Below are some example screenshots of the imaging we saw from strong signals. We used SDR# with the new PlutoSDR plugin, and set the sampling rate to 3 MSPS. On these screenshots we note that turning down the gain did not help, so these images were present in some way no matter the gain settings. There is probably still some optimization to go in the SDR# plugin, so it’s possible that imaging could be reduced with further work.

DAB Appearing at 79 MHz

DAB Appearing at 79 MHz

GSM at 133 MHz

GSM at 133 MHz

No imaging here (see next slide)

No imaging here (see next slide)

But moved 1 MHz up and there is heavy imaging

But moved 1 MHz up and there is heavy imaging

GSM @ 315 MHz

GSM @ 315 MHz

BCFM Pulsing in at 415 MHz

BCFM Pulsing in at 415 MHz

BCFM interference shows up like this at all frequencies above 800 MHz

BCFM interference shows up like this at all frequencies above 800 MHz

To test sensitivity we recorded audio on a few weak signals that did not have any images present, and we kept the gain at the highest it could go without the noise floor rising or images showing up.

Again we used SDR# with the PlutoSDR plugin, and set the sampling rate to 3 MSPS. We note that anything higher than 4 MSPS causes lost samples and thus jittery audio as this is the hardware limit of the PlutoSDR.

BCFM

This is a weak BCFM station. The PlutoSDR actually seemed to receive it better than the Airspy Mini. The RSP2 could not receive it, and the weak audio heard on the RSP2 is audio from an image.

PlutoSDR

PlutoSDR

Airspy Mini

Airspy Mini

SDRplay RSP2

SDRplay RSP2

161 MHz

This is a voice weather station. Here the PlutoSDR was very comparable to the Airspy Mini and RSP2. Not much sensitivity degradation in the ‘hacked’ expanded frequency range.

PlutoSDR

PlutoSDR

Airspy Mini

Airspy Mini

SDRplay RSP2

SDRplay RSP2

858 MHz

This is a digital trunking signal (there was no stable voice source this high to test with). Sensitivity is about the same as the other SDRs.

PlutoSDR

PlutoSDR

Airspy Mini

Airspy Mini

SDRplay RSP2

SDRplay RSP2

BCAM (Night)

A night time BCAM test. The PlutoSDR was coupled with a SpyVerter. Performance was quite good and on par with the Airspy Mini.

PlutoSDR

PlutoSDR

Airspy Mini

Airspy Mini

SDRplay RSP2

SDRplay RSP2

L-Band

Tested reception with a L-band patch antenna (no external LNA). Tested STD-C reception too. The PlutoSDR worked very well on L-band and had similar performance to the SDRplay. The Airspy is not good at L-band without an LNA and could not receive the STD-C channel by itself.

PlutoSDR

PlutoSDR

PlutoSDR STD-C

PlutoSDR STD-C

Airspy Mini

Airspy Mini

SDRplay RSP2

SDRplay RSP2

SDRplay RSP2 STD-C

SDRplay RSP2 STD-C

Conclusion

It’s clear that the PlutoSDR wasn’t made to be a general purpose high performance SDR, but rather a hackers/experimenters/learning SDR.  Performance in terms of out of band imaging is not great, and for any real listening filters may be required. That said, the performance is overall still not bad and overall still a bit better than an RTL-SDR or HackRF. With filtering the performance could be comparable to something like the Airspy Mini or SDRplay RSP2. Performance on L-band is very good, assuming you can filter or use a directional antenna to attenuate strong blocking signals. It’s also possible that further tweaks to the filter settings of the SDR# PlutoSDR plugin could improve imaging problems.

It’s also a bit disappointing that the maximum sample rate available is only 4 MSPS without drops. So this is the highest rate that you can use if you want to decode a signal, or listen to audio. For wideband waterfalls or spectrum analysis or other applications tolerant to dropped samples it should be possible to go up to the full 61.44 MSPS.

All in all, if you are interested in a low cost wideband SDR that does almost everything including TX, and are not too concerned about strong signals, images and overload, then this is still a great purchase at $99 USD (Digikey out of stock now, available for $149 on the Analog.com store). This SDR should be especially interesting to you if you are an SDR hacker/experimenter/student or are a fan of cheap SDRs/RTL-SDR/HackRF etc. If you are a ham or DXer and want something that just works with your high performance antennas and strong signals then you might look elsewhere.

On Twitter others have come to similar conclusions.

PlutoSDR SDR# Plugin + New Dual Core CPU Hack

A new plugin for SDR# has been released which allows SDR# to be used with the ADALM-PLUTO SDR. To use the plugin you’ll have to apply the frequency range hack first, which allows the PlutoSDR to tune to 70 – 6000 MHz. Then simply extract the plugin to the SDR# directory and add the key to the FrontEnds.xml file.

We tested the plugin out and found that it worked well with our PlutoSDR. The interface allows you to set the sample rate up to 19 MSPS, but anything over 4 MSPS causes dropped samples and anything over 5 MSPS is labelled as not supported. The advertised hardware limit of the PlutoSDR with no dropped samples is 4 MSPS, and we did notice audio jitter at 5 MSPS and above. Anything higher than 5 MSPS shows noticeable jitter in the waterfall display too. Note that this is not a problem of the plugin or SDR#, but rather of the hardware limitations.

Over on the PlutoSDR forums user jocover also discovered a new hack which allows you to enable dual-core support on the PlutoSDR. It’s not clear if this helps with anything useful yet, but maybe useful for some custom applications that make use of the CPU.

PlutoSDR running in SDR#
PlutoSDR running in SDR#

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.