Spektrum: New RTL-SDR Spectrum Analyzer Software

Recently a reader of RTL-SDR.com, Pavel wrote in to let us know about a new program called “Spektrum” which he has written. Spektrum runs on Windows and Linux and turns an RTL-SDR dongle into a spectrum analyzer in a similar way to rtl_power GUI front ends and RTLSDR Scanner. However one key improvement is that it is based on a version of rtl_power that has been modified by Pavel in order to make it more responsive and remove the need to wait until a full sweep is completed before you can see any results. The modified version of rtl_power can be found at https://github.com/pavels/rtl-sdr.

Spektrum also has an additional “relative mode” feature. This allows Spektrum to be easily used together with a wideband noise source to measure things like filter characteristics and the VSWR of antennas. See our previous tutorial on this here, but note that in our tutorial we used Excel instead of Spektrum to do relative measurements.

The Processing language was used to create Spektrum and Pavel has also released his processing library for accessing rtl_power functionality over at https://github.com/pavels/processing-rtlspektum-lib/releases.

Ready to use releases of Spektrum for Windows and Linux 64-Bit OSes can be downloaded from https://github.com/pavels/spektrum/releases. Note that there may be a bug with the current release which causes only a gray window to show, but we’ve contacted the author about it and it may be fixed soon.

Spektrum: A new spectrum analyzer program for the RTL-SDR
Spektrum: A new spectrum analyzer program for the RTL-SDR
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It is running fine on Ubuntu 18.04 64 bit. But I need a large window and large fonts to see it better. Also, it will be very useful to run with other much better SDR’s, using soapy_power instead of rtlpower. I don’t have enough skill and time to do that. 73 from YO3.


What frequency range does Spektrum cover?

gabriele ik2ugg

There was many poor Hamradio and use for all program the 32bit version.. the program i s very very intersting!!! . There is the possibility to run the update version on 32bit?
Thanks again
73 de IK2UGG

Robert Dohrenburg


I found something interesting on how to *fix* the dual bulk-in interface problem, I hope the Spektrum developers pay some attention on what I’ve found.

It appears that when two bulk-in interfaces are present the operating system/zadig/whatever places the rtl-sdr dongle on the second interface (bulk-in 1) instead of the first (bulk-in 0) and when spektrum tries to connect to interface 0 it hangs (gray screen). I have no deep knowledge of how spektrum works (still learning) but I found this behavior while using gnuradio.

In GNURadio:
I made a simple FM receiver using the RTL-SDR source component and when running it with the defaults (blank device arguments option) it didn’t work throwing the following error (RuntimeError: Failed to open rtlsdr device) To make it work I had to edit the device arguments option to include “rtl=1” instructing the sketch to use the second interface ( bulk-in 1)

I’m guessing here, so when spektrum prompts the user to select one of the two interfaces it always select the first one bulk-in 0 (a bug?)

I don’t know if this is a problem with windows or zadig. Gnuradio can successfully select the correct bulk-in interface why spektrum can’t?


Hi Robert,
Do you mean you discovered the problem (spektrum is trying to open the incorrect interface), or that you fixed the problem by doing something and now it works on your machine?


Hi Robert,
Do you mean you discovered the problem (spektrum is trying to open the incorrect interface), or that you fixed the problem by doing something and now it works on your machine?

Robert Dohrenburg

I just want to offer some information.

I have one computer with two flavors (old and new) of windows 10 PRO, same hardware except for the newly upgraded SSD. The old flavor is the original windows 10 PRO about two years old with current upgrades. The new flavor is a fresh install of windows 10 PRO using microsoft’s media creation tool. I insist, SAME computer different drives with windows 10 PRO installed at different points in time (old and new)

Now when trying to run spektrum on the new flavor I get the “Can’t open RTL-SDR Device” on both listed dongles. I reinstalled the drivers with zadig 2.4 in admin mode, same thing. On the old flavor computer spektrum works like a charm so I conclude that something with the latest windows 10 installation/upgrade is broken… as it usually happen.

Funny thing is that SDR# doesn’t work either but Console 3 does work.

I understand that the developer may have little time to troubleshoot this problem but out of curiosity he should try. Let me know if someone needs additional info as I have two twin win10 installations one that works and another that doesn’t.

just my 2 cents.


I am having trouble using the Spektrum on Windows 10. When I start the software, I get a dark blue screen with “Select Device” menu on the left hand side and also shows list of two (?) RTL devices as against mine only one connected as Generic RTL2832U OEM. But when I click to any one of this, it gives and error as “Can’t open RTL-SDR Device” and when I click on “OK” the software simply shuts down. Can you please guide me to sort out this problem?

Robert Dohrenburg

Same here Windows 10 updates broke something. I have it running fine in an original installation of windows 10. I upgraded my computer to a SSD and reinstalled windows 10 (latest media creation tool) same computer, same hardware, the only change is a new SSD and it fails as you described… two bulk interfaces and on both it fails to “open device”.
So every time I want to use spektrum I have to swap hard drives.


shit it doesn’t work in 32 bit like Windows XP,
that said not many do..


Where is a good place to figure out how all of the firmware and software work together for RTL-SDR?

I’m not too familar with visual C++, but somewhat with C++.

Also what is better Ubuntu windows 8 or Slackware? for running the SDR software? So far all I get is noise, and it changes some in pitch with various settings on HDSDR. I figure that I need it running before getting this to work.


Does not work on win10 x64, gray window in all compatibility modes. Author should be ashamed for releasing such a bummer. And you are telling me that 3 years are not enough for fixing that? LoOk At mE, I aM a PrOgRaMmEr tOo!


Ok, after some goofying around I managed to run Spektrum – but only the v1.02 release! What did not help was: reinstalling Visual C++ Redistributable for Visual Studio 2012 (I’ve even uninstaled it for a test, and Spektrum 1.02 runs without it); updating RTLSDR (RTL2832U) drivers (they were ok. nontheless, dongle worked with SDR# formerly); also running differen releases in a diferent compatybility mode did not make it.
What has actually helped was moving main folder to a desktop, located on a system partition and running it with RTLSDR plugged in.
Anyhow, flawless release would be much more appreciated. Sorry I’ve got irritated.

Beautiful Intelligent Talented Charming Honest

The project is opensource, so you could write a patch to fix exactly what you see as being wrong. Instead of just complaining.


How much have YOU contributed to the community? Other than rudeness and world record level ingratitude? You act like a very spoiled child.

Pavel, Thank you so much for the work you have done. I am looking forward to working with your code. As for your critic, please forgive him, it is apparently past his nap time.

Arthur Medzhinyan

Does not work, grey screen, delete this fake spectrum analyser.

Swerving Lemon

It’s not fake. I’m running it now on Win10 Pro 64 after replacing the RTL USB driver in the usual way with Zadig.
Please, put some effort in before concluding that the software is fake. The problem lies with Microsoft’s idiotic driver framework, not Pavel’s code.

Dr. Dan

Not to be rude but why do people keep calling these things spectrum analyzers?
This isn’t a spectrum analyzer, Without the ability to actually analyze the RF signal It becomes nothing more than a simple band scope.

I mean, after all, that’s what term “analyzers” means within the name “Spectrum Analyzer”. Without the ability to actually analyze the RF signal it becomes just a simple spectrum scope or band scope

In order for it to be classified as a spectrum analyzer, at the very minimum, it would need at least 2 markers with peak averaging or peak hold which could then automatically calculate and display the difference in dbc between to signals.

Preferably it should also have a means of normalizing the display. This would then give you the ability to use something like a wideband noise generator to simulate a tracking generator. This would then give you the ability to sweep filters and measure their frequency response.

I’m not sure how hard it would be to add those tools but doing so would transform this from a mere novelty toy into a really useful RF lab tool.


Because they are spectrum analyzers. Spectrum analyzers are generally defined as “An instrument primarily used to display power distribution of an incoming signal as a function of frequency”. Period. If you need a particular set of features, then you define your requirements and purchase the appropriate spectrum analyzer with the appropriate add-ons or build it yourself.



Maybe this is a better place to post…

is there a possibility of a “until manually reset” max hold? this would be a great tool to monitor a portion of spectrum over a period of time.

a wide-bandwidth waterfall would be useful, at some point, too – just to show a time history of signals…

RF Power Junkie

A great application, but we need a 32bit windows version built and released please!

gabriele ik2ugg

Yes, we are poor Hamradio and use for all program the 32bnit version.. the program i s very very intersting!!! 73 ik2ugg


Could somebody build a 32bit Ubuntu version? I can’t seem to get all the files. My testing laptop is 32 bit. I am not taking my new one out in the wild.

If not build, at least help me build one.


Derek H

Would love to have something like this for mac. Would love to have something like this on mac and not require a programmer to install.


Hi… it could work under 30 Mhz ?


It works ! You need to install Visual C++ Redistributable for Visual Studio 2012: vcredist_x64.exe to work.


I would like to modify sourceto better suit my application but can’t find rtlspectrum libraries in release area (https://github.com/pavels/processing-rtlspektum-lib/releases)
Can someone help?


12/2 and still a gray screen for me with various RTL’s plugged in. Using eartoearoak.com/software/rtlsdr-scanner.
works fine for now.


Guys, if you’re getting a plain gray screen are you sure you’ve plugged in an rtl-sdr dongle ahead of time?

I get the gray screen but only if I don’t have a dongle plugged in and ready for the software to connect to. If one is plugged in it works great.

This is so much faster than doing spreadsheet stuff by hand. I can interactively tune antenna and filters now!

Claudio i2NDT

grey screen for me as well!
win7 home edition…


Also just a grey box for me. Win 10 x64


Idem , j’ai une fenêtre grise sous Windows 7


Same, grey box on Win 7 x64. If the software doesn’t work, I don’t understand why you’d make a post about it and link to it.


You’re right, grey box in Windows 10

Paulo Bastos

I’ve got a gray screen too! Windows 10 64 Java 8.60 .