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


  1. 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.

    • rlwsdr

      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.


  2. Ken

    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…

  3. Michael

    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.


  4. 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.

    • David

      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.

  5. superkuh

    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!

  6. Brandon

    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.

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