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demantz / RFAnalyzer

Spectrum Analyzer for Android using the HackRF
GNU General Public License v2.0
854 stars 206 forks source link

More Spectrum (Bandwidth) #10

Open ghost opened 9 years ago

ghost commented 9 years ago

Hi I would like see more spectrum, I mean, now I'm watching less than 1MHz, but I would like to see 2MHz or more. With the same settings in SRD# software I watch more spectrum.

Thanks Best regards Roverano

aneitzel commented 9 years ago

Hi Roverano,

the biggest bandwith you can use with RTL-SDR on RFanalyzer should be 2,4Mhz. Only while demodulation of a signal is active at the moment you are limited to 1Mhz. For details i would refer to this thread: https://github.com/demantz/RFAnalyzer/issues/2

So turn demodulation OFF and spread the spectrum via a finger slide on your display. Can you confirm it working?

If you need more then that, HackRF is a alternative.

demantz commented 9 years ago

I'm currently working on a DSP library for Android using RenderScript to do heavy calculations on the device GPUs... will take a while til it is ready. But in the future it should hopefully enable RF Analyzer to get rid of the sample rate limitations for demod...

ghost commented 9 years ago

Anitzel, it is confirm. "the biggest bandwith you can use with RTL-SDR on RFanalyzer should be 2,4Mhz. Only while demodulation of a signal is active at the moment you are limited to 1Mhz."

Thannks

cmavr8 commented 9 years ago

Hi all, I'd also like more bandwidth. I'm using my RTL-SDR on PC with FFT size down to 128 and dwell to 16ms. This way I can scan about 15 Mhz in about 8 seconds.

Granted, accuracy is bad, and timing too, so it's not useful for most users. But it does help me see where my frequency hoping devices transmit!

So could we please have this before GPU implementation is done, although it takes a toll on performance?

demantz commented 9 years ago

Are you saying that your rtl dongle will switch frequency every 16ms to collect data of a wider spectrum? This is basically what I try to implement with the new scanning feature. This feature will be released before the GPU implementation (due to problems I have with RenderScript).

Currently I'm in the final stage of handing in my bachelor thesis and I have almost no time to work on anything else. But soon this will be over and then I will have enough time to work on all these open issues and features!

cmavr8 commented 9 years ago

Wait, no! I have no idea what Dwell is. I just use the option on RTLSDR-Scanner software that I run on my linux machine. And I know I need to lower it to 16ms. It can take values (in this program) from 16ms up to 8 mins. Sorry can't help you more.

Please do not feel pressure to do any of this right now. Your thesis is an important thing (I've written one, and starting another one in a month or so :P) so don't apologize for focusing on it. You've done a great job with this app already and we thank you for it :D.

Good luck and cu later!

EDIT: For future reference: From RTLSDR-Scanner's site: 'Dwell' controls how long each step is sampled for, longer times will result in more averaging of the signal. http://www.eartoearoak.com/software/rtlsdr-scanner

So, no, it's not a fancy trick...