Hey Dominic, Thanks for the explanation on all points! Yes the band at 900Mhz is rather quiet. Using your suggesting of tuning to a local FM station made the hex values more visually modulated, also it helps to know these values are signed 8 bit values. Right on! Now back to the lesson plan.
Thanks again, Brent On Fri, Feb 12, 2016 at 2:52 AM, Dominic Spill <[email protected]> wrote: > On 12 February 2016 at 06:43, Brent Thorne <[email protected]> wrote: >> >> Got to lesson 5 in the tutorial and I think I broke something after >> upgrading to hackrf-2015.07.2 (firmware and cpld images) . I can only >> capture 1kB using 'hackrf_transfer -r'. Help me understand if I'm >> doing something wrong. >> >> $ hackrf_info >> Found HackRF board 0: >> Board ID Number: 2 (HackRF One) >> Firmware Version: 2015.07.2 > > Looks good. You could also upgrade the CPLD too but if you're coming > from the 2014.08.1 release there's no need because there was no > change. > >> 19.9 MiB / 1.000 sec = 19.9 MiB/second >> 19.9 MiB / 1.000 sec = 19.9 MiB/second >> 19.9 MiB / 1.000 sec = 19.9 MiB/second >> ^CCaught signal 2 >> 4.7 MiB / 0.224 sec = 21.1 MiB/second > > This looks like it transferred much more than 1kB. How big is the > rx.raw output file? > >> $ hexdump rx.raw | head -10 >> 0000000 ff00 ffff ff00 ff00 ff00 ff00 0000 ff00 >> 0000010 ff00 ff00 ff00 ff00 0000 ffff ff00 ffff >> 0000020 fe00 ff00 ff00 ff00 ff00 ff00 ffff ff00 >> 0000030 ffff ff00 ff00 ff00 ff00 0000 ff00 0000 >> 0000040 ff00 ff00 fe00 ff00 ff00 ff00 ff00 ff00 >> 0000050 ff00 ff00 ff00 ff00 fe00 ff00 ff00 fe00 >> 0000060 0000 ff00 ff00 ff00 ff00 ff00 ff00 ff00 >> 0000070 ff00 ff00 ff00 ff00 ff00 fe00 ff00 ff00 >> 0000080 ff00 ff00 ff00 0000 ff00 ff00 ff00 ff00 >> 0000090 ffff ff00 ff00 ff00 ffff ff00 ff00 ff00 > > These values are signed int8s, which means what you're seeing here are > very low values, fluctuating around zero. This looks like valid data > to me. > > This brings us back to the command that you're using to capture the data: > >> $ hackrf_transfer -r rx.raw > > You will probably see more interesting data if you set some gain > levels and perhaps start out by tuning to a local FM station > frequency. -l -g set gain levels, -a enables the amplifier (although > I usually leave it off unless I need it) and -f will let you set the > frequency. I would expect you to see much more interesting data if > you set these. > > Please let me know how you get on with this. > > Thanks, > Dominic _______________________________________________ HackRF-dev mailing list [email protected] https://pairlist9.pair.net/mailman/listinfo/hackrf-dev
