On 01/19/2017 04:01 PM, Marc Pàmies Massip wrote: > Thank you Cinaed, > > After doing the test with a sample rate of 8MHz I saw that both columns > are not always equal (as you can see in the image). I am not using any > hub, does it mean that I should use another computer or it doesn't > suppose a big problem?
It's close enough. You should use a binary search and find the maximum sampling rate. This is the maximum sampling rate without the CPU load of the SDR on the computer. Then a crude rule of thumb would be to use half the maximum sampling rate as a starting point. We don't know anything about your computer so we can't comment. Have you tried listening to a wide band FM station - or listening to audio on any other band than 900 MHz? > > The hackrf_info command tells me that my hackrf's version is 2014.08.1. > I will ask in the other mailing list if I should do a firmware update > because I don't know how to check which is the latest version. > > Marc. >> >> On 19/01/2017 23:34:18, Cinaed Simson <[email protected]> wrote: >> >> On 01/19/2017 01:28 AM, Marc Pàmies Massip wrote: >> > Oh, really? I was using a HackRF-One and sampling at 10MHz. >> >> I was betting on a RTL dongle. >> >> And I'm guessing SDR# is running on Windows. >> >> You should also try a WBFM channel - between 88-108 MHz. >> >> There could be Windows USB driver issues - or the version of the HackRF >> One libraries and utilities doesn't match the firmware. >> >> Try >> >> hackrf_transfer -r NUL -s 8000000 >> >> The two columns should be equal in magnitude - otherwise the >> USB/computer are to slow for 8 MHz sampling - which is minimum >> requirement. >> >> Don't use a USB hub. >> >> And post >> >> hackrf_info >> >> on the above information on the mailing list >> >> [email protected] >> >> - someone on the list may have seen the problem before. >> >> I know next to nothing about Windows. >> >> >> > >> > 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 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] >> >> > https://lists.gnu.org/mailman/listinfo/discuss-gnuradio >> >> > >> >> >> >> >> >> _______________________________________________ >> >> Discuss-gnuradio mailing list >> >> [email protected] >> >> https://lists.gnu.org/mailman/listinfo/discuss-gnuradio >> _______________________________________________ Discuss-gnuradio mailing list [email protected] https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
