So, let's really look at what you receive there. What's your antenna? When you connect a QT GUI time sink, what's (roundabout) your maximum amplitude coming out of the USRP Source?
Best regards, Marcus On Fri, 2019-06-14 at 23:25 -0500, Daniel Andres Palacios wrote: > Hello Kyeong, > About gain level, it was a desperate measure, in my eagerness to get > signals. If someone has used managed to detect FM signals and can > give me the parameters used, > I would appreciate it. > > Thanks > > > > > On Thu, Jun 13, 2019 at 10:45 PM Kyeong Su Shin <[email protected] > > wrote: > > Hello Daniel, > > > > A few things to note: > > > > -Gain level of USRP B200 does not go up to 120 dB. Sure, GNU Radio > > or UHD won't complain about this, but it maxes out at around 70 dB > > (I do not remember the exact number). > > > > -My eyes are untrained (I did study sigint before, but it's been a > > few years since then), so I cannot tell which peaks are spurious > > and which peaks are true WBFM signals by simply looking a > > periodogram. However, it seems like the signal detector block is > > not detecting some serious (~-40 to -20 dBFS) peaks in the > > spectrum. If those peaks are FM signals, then the detector block is > > either misconfigured or is not suitable for the task. If those > > peaks are not FM signals (are spurious signals or unwanted > > interferences) and if you are not seeing actual FM signals on your > > periodogram, then you will need to move your receiver to elsewhere > > or get a better antenna (and may have to decrease the gain of the > > receiver). > > > > -gr-inspector's signal detector uses energy detection to detect > > signals, which works on most types of signals but is also > > suboptimal (in terms of the detection accuracy). You may want to > > come up with your own detector block that exploits the > > characteristics of the FM signal if you want to maximize the > > detection accuracy (in terms of P_d and P_fa). > > > > Regards, > > Kyeong Su Shin > > > > 보낸 사람: Daniel Andres Palacios <[email protected]> 대신 Discuss- > > gnuradio <[email protected]> > > 보낸 날짜: 2019년 6월 14일 금요일 오전 6:14:07 > > 받는 사람: Sebastian Müller > > 참조: [email protected] > > 제목: Re: [Discuss-gnuradio] Live fm detection gr-inspector > > > > OK, my bad. > > > > Here is my actual configuration. But again, signals appear and > > disappear. > > Even when I try to cath a fm station, if the GUI Inspector is not > > set to manual, a get the same behavior > > > > Thank you. > > > > > > > > On Thu, Jun 13, 2019 at 2:11 PM Sebastian Müller <[email protected]> > > wrote: > > > I just noticed something else: > > > The USRP sample rate is set to 500kHz, not 20MHz. So you are only > > > looking at 2.5 % of the target spectrum! It is also possible, > > > that > > > there are just no signals in that particular section. > > > > > > Best, > > > > > > Sebastian Müller > > > [email protected] > > > PGP ID DC2AA3EE > > > > > > Am 13. Juni 2019 um 20:20:24, Sebastian Müller ([email protected]) > > > schrieb: > > > > Hi Daniel, > > > > > > > > from what you tell us, I conclude this is not an issue with gr- > > > inspector but rather with > > > > generally receiving signals. > > > > If you use the QT GUI Sink for instance instead, you will see > > > the same (empty) spectrum. > > > > I would recommend to try and get better reception, until you > > > can distinguish signals > > > > visually in the spectrum manually. Are you using the correct > > > antenna for this frequency > > > > range? Is this antenna positioned in a beneficial location for > > > reception? Have you played > > > > around with the Rx gain of the USRP? > > > > > > > > Best, > > > > > > > > Sebastian Müller > > > > [email protected] > > > > PGP ID DC2AA3EE > > > > > > > > Am 13. Juni 2019 um 19:10:59, Daniel Andres Palacios ( > > > [email protected]) schrieb: > > > > > Thanks for your reply > > > > > > > > > > I trying to detect and classify all fm transmitted stations > > > in my country, > > > > > with the gr-inspector OOT. > > > > > In my country (Colombia) it goes from 87,9 to 107.9 MHZ. > > > > > I only have an USRP B200 and think that if I set the center > > > frequency at 98 > > > > > MHZ and put a bandwidth of 20MHZ its posible to get my goal. > > > But actually > > > > > im not getting signals detected > > > > > [image: Captura de pantalla de 2019-06-13 11-17-05.png] > > > > > > > > > > On Tue, Jun 11, 2019 at 12:53 PM Müller, Marcus (CEL) > > > > > wrote: > > > > > > > > > > > Hi Daniel, > > > > > > > > > > > > please remember to be specific when asking a question: > > > "best way" is a > > > > > > bit ambiguous, and "I'm not getting a good result" > > > definitely is > > > > > > insufficient for us to help you make things work better. > > > What doesn't > > > > > > work sufficiently well? What happens instead? > > > > > > > > > > > > Best regards, > > > > > > Marcus > > > > > > > > > > > > On Tue, 2019-06-11 at 12:36 -0500, Daniel Andres Palacios > > > wrote: > > > > > > > Hi to everyone. > > > > > > > > > > > > > > What is the best way to receive all fm modifications. I'm > > > usigin an B200 > > > > > > USRP. > > > > > > > I think that putting the center frequency at 98M and a > > > bandwidth of 20M > > > > > > is a good way,but I'm not getting a good result. > > > > > > > > > > > > > > The idea is to detect all fm center frequencies using gr- > > > inspector > > > > > > > _______________________________________________ > > > > > > > Discuss-gnuradio mailing list > > > > > > > [email protected] > > > > > > > https://lists.gnu.org/mailman/listinfo/discuss-gnuradio > > > > > > > > > > > > > > > > > > > > > -- > > > > > *Daniel Andrés Palacios Carabalí* > > > > > *Student of Telemathics engineering* > > > > > *Icesi University- Cali, Colombia* > > > > > *===========================* > > > > > *Estudiante de Ingeniería Telemática* > > > > > *Universidad Icesi. - Cali, Colombia* > > > > > _______________________________________________ > > > > > 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 > > > > > > -- > > Daniel Andrés Palacios Carabalí > > Student of Telemathics engineering > > Icesi University- Cali, Colombia > > =========================== > > Estudiante de Ingeniería Telemática > > Universidad Icesi. - Cali, Colombia > > > _______________________________________________ > Discuss-gnuradio mailing list > [email protected] > https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
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