On 01/19/2017 02:16 PM, Marc Pàmies Massip wrote: > Hey Paul, > > You are right, if I reduce the gain the peaks are reduced too. Do yo > have an explanation for it?
There are 3 gain settings on the HackRF One, namely, RF gain, IF gain, base band gain. The RF gain (which I presume is the LNA in SDR#) should be set to 0. Unless you live in a rural area, you run the risk of smoking the LNA. See https://greatscottgadgets.com/sdr Lesson 5 is an introduction to the HackRF One. > > Playing with SDR# I have seen that setting the LNA noise and the VGA > noise to 0dB all the peaks are removed. If then I increase the LNA noise > and maintain VGA noise to 0dB the peaks appear again (as it gets higher > more peaks appear). And finally by increasing the VGA noise the peaks > just go higher with the rest of the spectrum. However, if after setting > both gains to 0dB I start increasing the VGA gain a few peaks appear > too, but not as many as in the other case. Does it makes sense to you? > > Many thanks for your reply, > > Marc. >> >> On 19/01/2017 12:19:49, Garver, Paul W <[email protected]> wrote: >> >> If you change the receiver gain, does anything happen to the peaks? >> Try lowering it. >> >> Paul Garver >> >> >> On Jan 19, 2017, at 4:32 AM, Marc Pàmies Massip <[email protected] >> <mailto:[email protected]>> wrote: >> >>> Oh, really? I was using a HackRF-One and sampling at 10MHz. >>> >>> Now I've tried with different sample rates (8MHz, 10MHz, 12.5MHz and >>> 16MHz) and the peaks are always there. Maybe it's true that they >>> appear more often for higher sample rates, but I am not able to make >>> them disappear. >>> >>> Marc. >>>> >>>> On 19/01/2017 9:38:34, Cinaed Simson <[email protected] >>>> <mailto:[email protected]>> wrote: >>>> >>>> On 01/18/2017 01:31 PM, Marc Pàmies Massip wrote: >>>> > Hi, >>>> > >>>> > Maybe this is a stupid question for experts in SDR, but I haven't >>>> find a >>>> > clear explanation yet. I know it is normal to have a DC offset in the >>>> > center of the spectrum, but I am surprised by the amount of static >>>> peaks >>>> > that I see sometimes in specific bands (you can find attached some >>>> > images to better understand what am I talking about). It is >>>> obvious that >>>> > those are not "real" signals, in fact when I re-tune the SDR >>>> peripheral >>>> > they don't move according to the frequency displacement. I want to >>>> > understand if it is due to a software problem (the screenshots were >>>> > taken from SDR#) or if it has something to do with the hardware >>>> (maybe >>>> > those are just harmonics from some kind of square signal, i.e >>>> clock). I >>>> > am worried because they are extremely strong and because of this I >>>> could >>>> > have trouble detecting weaker signals nearby. >>>> > >>>> > Summarising, my questions are: >>>> > >>>> > - What causes those peaks? >>>> > - Is it necessary to remove them for a proper signal detection? >>>> > >>>> > Thanks in advance, >>>> > >>>> > Marc. >>>> >>>> You haven't indicated what hardware you used or the sampling rate. >>>> >>>> Try reducing the sampling rate - the sampling rate used may be >>>> unstable. >>>> >>>> > >>>> > >>>> > _______________________________________________ >>>> > Discuss-gnuradio mailing list >>>> > [email protected] <mailto:[email protected]> >>>> > https://lists.gnu.org/mailman/listinfo/discuss-gnuradio >>>> > >>>> >>>> >>>> _______________________________________________ >>>> Discuss-gnuradio mailing list >>>> [email protected] <mailto:[email protected]> >>>> https://lists.gnu.org/mailman/listinfo/discuss-gnuradio >>> _______________________________________________ >>> Discuss-gnuradio mailing list >>> [email protected] <mailto:[email protected]> >>> https://lists.gnu.org/mailman/listinfo/discuss-gnuradio _______________________________________________ Discuss-gnuradio mailing list [email protected] https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
