Before / After comparison?

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Longo
Posts: 2
Joined: Tue Dec 05, 2017 1:42 am

Before / After comparison?

Post by Longo » Tue Dec 05, 2017 1:53 am

Hi all,

Is there SDR package that will scan a large chunk of the spectrum several times, taking an average over say 10 sweeps, then repeat the process with a device-to-be-tested turned on, allowing you to see what changed as a result?

I just want to know what the stuff around my home is chucking out :)

I have a NooElec NESDR Mini 2+ (RTL2832 + R820T2) for what it's worth. Would love an Ettus B200, but I feel good tools are wasted in untrained hands.

rtlsdrblog
Site Admin
Posts: 2563
Joined: Mon Nov 19, 2012 11:54 pm

Re: Before / After comparison?

Post by rtlsdrblog » Tue Dec 05, 2017 10:37 am

Yes look up rtl_power. Basically you can do an integration over a set time period, save the results and plot it, then make your changes and run rtl_power again.

Kenn
Posts: 51
Joined: Fri Apr 08, 2016 8:43 pm

Re: Before / After comparison?

Post by Kenn » Tue Dec 05, 2017 4:14 pm


Longo
Posts: 2
Joined: Tue Dec 05, 2017 1:42 am

Re: Before / After comparison?

Post by Longo » Thu Dec 07, 2017 3:10 pm

Thanks both! After much pains to install qspectrumanalyser dependancies on OSX, it does seem to do a pretty good job of plotting a frequency range average. Very nice tool :)

Image

However this repetitive patten i'm seeing across the frequency range is a bit of a worry. Is my device broken? Or perhaps i need a different antenna? Or maybe there's some very strong signals coming in that overpower it? Hm.

The downside to this tool however is that I can not collect the data for the averages plotted, in order to subtract two runs with devices turned on/off. So i'll try out the more manual rtl_power now :)


rtlsdrblog
Site Admin
Posts: 2563
Joined: Mon Nov 19, 2012 11:54 pm

Re: Before / After comparison?

Post by rtlsdrblog » Sat Dec 09, 2017 10:05 am

That's just the rolloff of the bandwidth that you're seeing. Look in the setting for a crop factor setting, and put it up to 20-30%. Should solve those banding issues.
Longo wrote:
Thu Dec 07, 2017 3:10 pm
Thanks both! After much pains to install qspectrumanalyser dependancies on OSX, it does seem to do a pretty good job of plotting a frequency range average. Very nice tool :)

Image

However this repetitive patten i'm seeing across the frequency range is a bit of a worry. Is my device broken? Or perhaps i need a different antenna? Or maybe there's some very strong signals coming in that overpower it? Hm.

The downside to this tool however is that I can not collect the data for the averages plotted, in order to subtract two runs with devices turned on/off. So i'll try out the more manual rtl_power now :)

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