# Dvb-t project with two USRPN200 devices failure **URL:** \ **Category:** GNU Radio\ **Created:** [March 31, 2014, 12:23pm UTC](https://www.ruby-forum.com/t/dvb-t-project-with-two-usrpn200-devices-failure/240161 "2014-03-31T12:23:13Z")\ **Posts on this page:** 11\ **Page:** 1
**Author:** ![musicdenotation](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/ea666f/32.png) [@musicdenotation](https://www.ruby-forum.com/u/musicdenotation)\ **Post date:** [March 31, 2014, 12:23pm UTC](https://www.ruby-forum.com/t/dvb-t-project-with-two-usrpn200-devices-failure/240161/1 "2014-03-31T12:23:13Z")
Hi all, I am using ubuntu 13.04, GNURADIO 3.7. I cannot transmit or receive using two (USRPN200 + XCRV2450 d.board+VERT2450 antennas) devices for DVB-T project. Here is the dvb-t project: [GitHub - BogdanDIA/gr-dvbt: DVB-T implementation in gnuradio](https://github.com/BogdanDIA/gr-dvbt) It will be very helpful and appreciated if you help me. If someone tested it or can do it, please let me know. As far as I know someone tested it with N210 model. I think this failure is due to high noise/interference or smt. else. However I tested it already with all possible configurations. I also attach my .grc files. ---
**Author:** ![nesazeri](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/n/e19adc/32.png) [@nesazeri](https://www.ruby-forum.com/u/nesazeri)\ **Post date:** [March 31, 2014, 5:24pm UTC](https://www.ruby-forum.com/t/dvb-t-project-with-two-usrpn200-devices-failure/240161/2 "2014-03-31T17:24:10Z")
Hi, not having access to my setup for now but for the beginning you could try recording the spectrum with your USRP and then use the file source to decode the signal offline. There is a script file apps/capture.sh that I usually use to capture data. You may tweak it for your needs (frequency, gain). Sometimes it was reported that on old cpus the processing power is not enough so that the result is an overflow (you directly see a long OOO message in this case). Try to see if this is the case. One way to reduce the overhead is to run the receiving flow directly from command line instead of gnuradio-companion (e.g. ./top\_block \> out.txt) after you have generated the flowgraph. The gnuradio-companion cannot cope with big amount of data when the blocks gets out a lot of text. Bogdan On Monday, March 31, 2014 1:22 PM, Nasi [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: Hi all, I am using ubuntu 13.04, GNURADIO 3.7. I cannot transmit or receive using two (USRPN200 + XCRV2450 d.board+VERT2450 antennas) devices for DVB-T project. Here is the dvb-t project:[GitHub - BogdanDIA/gr-dvbt: DVB-T implementation in gnuradio](https://github.com/BogdanDIA/gr-dvbt) It will be very helpful and appreciated if you help me. If someone tested it or can do it, please let me know. As far as I know someone tested it with N210 model. I think this failure is due to high noise/interference or smt. else. However I tested it already with all possible configurations. I also attach my .grc files. ---
**Author:** ![nesazeri](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/n/e19adc/32.png) [@nesazeri](https://www.ruby-forum.com/u/nesazeri)\ **Post date:** [March 31, 2014, 5:38pm UTC](https://www.ruby-forum.com/t/dvb-t-project-with-two-usrpn200-devices-failure/240161/3 "2014-03-31T17:38:46Z")
Hi, Thanks! I am using collected data also as you say. I am using sampling rate of 1 Mbps instead of 10 Mbps which must be the same for static transmission. Isn’t it? Mon, 31 Mar 2014 08:23:01 -0700 (PDT) от Bogdan D. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid): > Hi, not having access to my setup for now but for the beginning you could try > recording the spectrum with your USRP and then use the file source to decode the > signal offline. There is a script file apps/capture.sh that I usually use to > capture data. You may tweak it for your needs (frequency, gain). > > Sometimes it was reported that on old cpus the processing power is not enough so > that the result is an overflow (you directly see a long OOO message in this case). > Try to see if this is the case. > > One way to reduce the overhead is to run the receiving flow directly from command > line instead of gnuradio-companion (e.g. ./top\_block \> out.txt) after you have > generated the flowgraph. The gnuradio-companion cannot cope with big amount of > data when the blocks gets out a lot of > text. ---
**Author:** ![nesazeri](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/n/e19adc/32.png) [@nesazeri](https://www.ruby-forum.com/u/nesazeri)\ **Post date:** [March 31, 2014, 5:53pm UTC](https://www.ruby-forum.com/t/dvb-t-project-with-two-usrpn200-devices-failure/240161/4 "2014-03-31T17:53:58Z")
ohhh, now I understand. It produces UUUU in the transmitter side - which probably means underflow with my laptop. Do you know how to decrease this power? Mon, 31 Mar 2014 08:44:49 -0700 (PDT) от Bogdan D. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid): > I am using collected data also as > you say. > One way to reduce the overhead is to run the receiving flow directly from command > line instead of gnuradio-companion (e.g. ./top\_block \> out.txt) after > you have generated the flowgraph. The gnuradio-companion cannot cope > with big amount of data when the blocks gets out a lot of > text. ---
**Author:** ![nesazeri](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/n/e19adc/32.png) [@nesazeri](https://www.ruby-forum.com/u/nesazeri)\ **Post date:** [March 31, 2014, 5:46pm UTC](https://www.ruby-forum.com/t/dvb-t-project-with-two-usrpn200-devices-failure/240161/5 "2014-03-31T17:46:57Z")
For dvbt the bandwidth is around 9.14Msps so with the rational resampler you need to set-up the USRP at 10Msps. 1Msps will not work as only a part of the spectrum will be received. Bogdan On Monday, March 31, 2014 6:36 PM, Nasi [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: Hi, Thanks! I am using collected data also as you say. I am using sampling rate of 1 Mbps instead of 10 Mbps which must be the same for static transmission. Isn’t it? Mon, 31 Mar 2014 08:23:01 -0700 (PDT) от Bogdan D. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid): Hi, not having access to my setup for now but for the beginning you could try recording the spectrum with your USRP and then use the file source to decode the signal offline. There is a script file apps/capture.sh that I usually use to capture data. You may tweak it for your needs (frequency, gain). Sometimes it was reported that on old cpus the processing power is not enough so that the result is an overflow (you directly see a long OOO message in this case). Try to see if this is the case. One way to reduce the overhead is to run the receiving flow directly from command line instead of gnuradio-companion (e.g. ./top\_block \> out.txt) after you have generated the flowgraph. The gnuradio-companion cannot cope with big amount of data when the blocks gets out a lot of text. Bogdan On Monday, March 31, 2014 1:22 PM, Nasi [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: Hi all, I am using ubuntu 13.04, GNURADIO 3.7. I cannot transmit or receive using two (USRPN200 + XCRV2450 d.board+VERT2450 antennas) devices for DVB-T project. Here is the dvb-t project: [GitHub - BogdanDIA/gr-dvbt: DVB-T implementation in gnuradio](https://github.com/BogdanDIA/gr-dvbt) It will be very helpful and appreciated if you help me. If someone tested it or can do it, please let me know. As far as I know someone tested it with N210 model. I think this failure is due to high noise/interference or smt. else. However I tested it already with all possible configurations. I also attach my .grc files. – NE ---
**Author:** ![nesazeri](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/n/e19adc/32.png) [@nesazeri](https://www.ruby-forum.com/u/nesazeri)\ **Post date:** [March 31, 2014, 6:09pm UTC](https://www.ruby-forum.com/t/dvb-t-project-with-two-usrpn200-devices-failure/240161/6 "2014-03-31T18:09:11Z")
One thing I did once and worked are: 1. Use a file sink instead of USRP when transmitting. Then, once the file is generated send the samples from file (opened in a file source) directly to USRP. That will need a good harddrive with at least 80MB/s read speed, a SSD will work probably. 2. Do the above but write the file int RAM like dd if=yourfile.bin of=/dev/ram0 - you may need to give root access. Then open /dev/ram0 in a file source and send it to USRP. This will consume you RAM and will potentiall lock your laptop if the .bin file is bigger than RAM size. But, indeed you probably need a better computer. Bogdan On Monday, March 31, 2014 6:59 PM, Marcus M. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: -----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 I’m afraid you can’t reduce needed sample rate for a fixed bandwidth. You need a stronger laptop. Often, plugging it into mains power helps. Marcus On 31.03.2014 17:52, Nasi wrote: > > work as only a part of the spectrum will be received. > > you say. > > offline. There is a script file apps/capture.sh that I usually > > line instead of gnuradio-companion (e.g. ./top\_block \> out.txt) > > I am using ubuntu 13.04, GNURADIO 3.7. I cannot transmit or > > configurations. I also attach my .grc files. > > \_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_ Discuss-gnuradio > mailing list [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) > [Discuss-gnuradio Info Page](https://lists.gnu.org/mailman/listinfo/discuss-gnuradio) -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 Comment: Using GnuPG with Thunderbird - [http://www.enigmail.net/](http://www.enigmail.net/) iQEcBAEBAgAGBQJTOZDPAAoJEBQ6EdjyzlHtDWwIALcmUMVs7Rrx/WdFtqJ//Fxn tzMvsVrDOKBu+5AnmmbVZ20dVulN2lcZ25vZScpFYKOAbe5TwRy2XTsFODHItGNF dhmyOQNLVArDSSQuWTLSnMODKEUMCgU/sxyDtal0SVz6KuCSjjwP/exgaKHtNweU tQid+PdH0JTZ/5iqvtQyHJhwy0rcl0RIK8ig0MXhoQG8IQVl2lKZXUtlOle1wMsC w5oed0uop0d1J4bWDxC3oBRd6DfSCLx9avXtCHEFdgiAZSkFPva0XhJbimm3K8GP V6qzH2S29eojRZYQHqlWxy8ISMG8SCr0Ii2joHv6iESCB9cgK1KkWrECMc0Ltvk= =HjFO -----END PGP SIGNATURE----- ---
**Author:** ![nesazeri](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/n/e19adc/32.png) [@nesazeri](https://www.ruby-forum.com/u/nesazeri)\ **Post date:** [March 31, 2014, 6:13pm UTC](https://www.ruby-forum.com/t/dvb-t-project-with-two-usrpn200-devices-failure/240161/7 "2014-03-31T18:13:51Z")
Thanks a lot! I will try them too… Mon, 31 Mar 2014 09:08:04 -0700 (PDT) от Bogdan D. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid): > Marcus > > > > For dvbt the bandwidth is around 9.14Msps so with the rational > > > > > > now but for the beginning you could try recording the spectrum > > > with your USRP and then use the file source to decode the signal > > > offline. There is a script file apps/capture.sh that I usually > > > use to capture data. You may tweak it for your > > > needs (frequency, > > > after you have generated the flowgraph. The gnuradio-companion > > > cannot cope with big amount of data when the blocks gets out a lot > > > of text. > > > > > > Bogdan > > > > > > On Monday, > > > March 31, 2014 1:22 PM, Nasi \< [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) \> > > > > > > I think this failure is due to high > > > noise/interference or smt. > > > > > > – NE \_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_ Discuss-gnuradio ---
**Author:** ![nesazeri](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/n/e19adc/32.png) [@nesazeri](https://www.ruby-forum.com/u/nesazeri)\ **Post date:** [March 31, 2014, 6:00pm UTC](https://www.ruby-forum.com/t/dvb-t-project-with-two-usrpn200-devices-failure/240161/8 "2014-03-31T18:00:24Z")
-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 I’m afraid you can’t reduce needed sample rate for a fixed bandwidth. You need a stronger laptop. Often, plugging it into mains power helps. Marcus On 31.03.2014 17:52, Nasi wrote: > > work as only a part of the spectrum will be received. > > you say. > > offline. There is a script file apps/capture.sh that I usually > > line instead of gnuradio-companion (e.g. ./top\_block \> out.txt) > > I am using ubuntu 13.04, GNURADIO 3.7. I cannot transmit or > > configurations. I also attach my .grc files. > > \_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_ Discuss-gnuradio > mailing list [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) > [Discuss-gnuradio Info Page](https://lists.gnu.org/mailman/listinfo/discuss-gnuradio) -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 Comment: Using GnuPG with Thunderbird - [http://www.enigmail.net/](http://www.enigmail.net/) iQEcBAEBAgAGBQJTOZDPAAoJEBQ6EdjyzlHtDWwIALcmUMVs7Rrx/WdFtqJ//Fxn tzMvsVrDOKBu+5AnmmbVZ20dVulN2lcZ25vZScpFYKOAbe5TwRy2XTsFODHItGNF dhmyOQNLVArDSSQuWTLSnMODKEUMCgU/sxyDtal0SVz6KuCSjjwP/exgaKHtNweU tQid+PdH0JTZ/5iqvtQyHJhwy0rcl0RIK8ig0MXhoQG8IQVl2lKZXUtlOle1wMsC w5oed0uop0d1J4bWDxC3oBRd6DfSCLx9avXtCHEFdgiAZSkFPva0XhJbimm3K8GP V6qzH2S29eojRZYQHqlWxy8ISMG8SCr0Ii2joHv6iESCB9cgK1KkWrECMc0Ltvk= =HjFO -----END PGP SIGNATURE----- ---
**Author:** ![nesazeri](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/n/e19adc/32.png) [@nesazeri](https://www.ruby-forum.com/u/nesazeri)\ **Post date:** [April 18, 2014, 12:54am UTC](https://www.ruby-forum.com/t/dvb-t-project-with-two-usrpn200-devices-failure/240161/9 "2014-04-18T00:54:32Z")
Yes, it’s possible. The use of the rational re-sampler is to be compatible with commercial DVB-T receivers. If you’re just interested in USRP to USRP, then it’s okay to use a 10 Msps sample rate. The signal will be slightly wider than a standard 8 MHz signal at 9.142857 Msps. You can modify my DVB-T Transport Stream bitrate calculator to determine the required bitrates at 10 Msps. > Ron ---
**Author:** ![nesazeri](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/n/e19adc/32.png) [@nesazeri](https://www.ruby-forum.com/u/nesazeri)\ **Post date:** [April 17, 2014, 4:08pm UTC](https://www.ruby-forum.com/t/dvb-t-project-with-two-usrpn200-devices-failure/240161/10 "2014-04-17T16:08:53Z")
Can I trans/receive without Rational Resampler? It distorts the signal too much ☹ Mon, 31 Mar 2014 20:12:27 +0400 от Nasi [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid): > > I’m afraid you can’t reduce needed sample rate for a fixed bandwidth. > > > > > > On Monday, March 31, 2014 6:36 PM, Nasi \< [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) \> > > > > > > > > Mon, 31 Mar 2014 08:23:01 -0700 (PDT) ?? Bogdan D. > > > > \< [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) \>: Hi, not having access to my setup for > > > > now but for the beginning you could try recording the spectrum > > > > with your USRP and then use the file source to decode the signal > > > > offline. There is a script file apps/capture.sh that I usually > > > > use to capture data. You may tweak it for your > > > > needs (frequency, > > > > after you have generated the flowgraph. The gnuradio-companion > > > > cannot cope with big amount of data when the blocks gets out a lot > > > > of text. > > > > > > > > Bogdan > > > > > > > > On Monday, > > > > March 31, 2014 1:22 PM, Nasi \< [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) \> > > > > > > > > I think this failure is due to high > > > > noise/interference or smt. > > > > > > > > – NE \_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_ Discuss-gnuradio ---
**Author:** ![nesazeri](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/n/e19adc/32.png) [@nesazeri](https://www.ruby-forum.com/u/nesazeri)\ **Post date:** [April 20, 2014, 5:41pm UTC](https://www.ruby-forum.com/t/dvb-t-project-with-two-usrpn200-devices-failure/240161/11 "2014-04-20T17:41:17Z")
Not actually, not possible. I tested today. It does not receive anything. Thu, 17 Apr 2014 15:53:39 -0700 от Ron E. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid): > [dtv-utils/dvbtrate.c at master · drmpeg/dtv-utils · GitHub](https://github.com/drmpeg/dtv-utils/blob/master/dvbtrate.c) > > > > Thanks a lot! I will try them too… > > > > > > Mon, 31 Mar 2014 09:08:04 -0700 (PDT) от Bogdan > > > Diaconescu [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) : > > > > > > > One thing I did once and worked are: > > > > > > > > 1. Use a file sink instead of USRP when > > > > transmitting. Then, once the file is > > > > generated send the samples from file (opened > > > > in a file source) directly to USRP. That > > > > will need a good harddrive with at least > > > > 80MB/s read speed, a SSD will work probably. > > > > > > > > 2. Do the above but write the file int RAM > > > > like dd if=yourfile.bin of=/dev/ram0 - you > > > > may need to give root access. Then open > > > > /dev/ram0 in a file source and send it to > > > > USRP. This will consume you RAM and will > > > > potentiall lock your laptop if the .bin file > > > > is bigger than RAM size. > > > > > > > > But, indeed you probably need a better > > > > computer. > > > > > > > > Bogdan > > > > > > > > On Monday, March 31, > > > > 2014 6:59 PM, Marcus Müller > > > > [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > > > > -----BEGIN PGP SIGNED > > > > MESSAGE----- > > > > Hash: SHA1 > > > > > > > > I’m afraid you can’t reduce needed > > > > sample rate for a fixed bandwidth. > > > > > > > > You need a stronger laptop. Often, > > > > plugging it into mains power helps. > > > > > > > > Marcus > > > > > > > > On 31.03.2014 17:52, Nasi wrote: > > > > > > > > > ohhh, now I understand. It > > > > > produces UUUU in the transmitter > > > > > side - > > > > > which probably means underflow > > > > > with my laptop. Do you know how to > > > > > decrease this power? > > > > > > > > > > Mon, 31 Mar 2014 08:44:49 -0700 > > > > > (PDT) ?? Bogdan D. > > > > > \< [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) \>: > > > > > > > > > > > For dvbt the bandwidth is > > > > > > around 9.14Msps so with the rational > > > > > > resampler you need to > > > > > > set-up the USRP at 10Msps. 1Msps > > > > > > will not > > > > > > work as only a part of the > > > > > > spectrum will be received. > > > > > > > > > > > > Bogdan > > > > > > > > > > > > On Monday, March 31, 2014 > > > > > > 6:36 PM, Nasi \< [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) \> > > > > > > wrote: Hi, > > > > > > > > > > > > Thanks! > > > > > > > > > > > > I am using collected data > > > > > > also as > > > > > > you say. > > > > > > I am using sampling rate of > > > > > > 1 Mbps instead of 10 Mbps which must > > > > > > be the same for static > > > > > > transmission. Isn’t it? > > > > > > > > > > > > Mon, 31 Mar 2014 08:23:01 > > > > > > -0700 (PDT) ?? Bogdan D. > > > > > > \< [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) \>: > > > > > > Hi, not having access to my setup > > > > > > for > > > > > > now but for the beginning > > > > > > you could try recording the spectrum > > > > > > with your USRP and then use > > > > > > the file source to decode the signal > > > > > > offline. There is a script > > > > > > file apps/capture.sh that I usually > > > > > > use to capture data. You > > > > > > may tweak it for your needs > > > > > > (frequency, > > > > > > gain). > > > > > > > > > > > > Sometimes it was reported > > > > > > that on old cpus the processing > > > > > > power > > > > > > is not enough so that the > > > > > > result is an overflow (you directly > > > > > > see > > > > > > a long OOO message in this > > > > > > case). Try to see if this is the > > > > > > case. > > > > > > > > > > > > One way to reduce the > > > > > > overhead is to run the receiving > > > > > > flow > > > > > > directly from command > > > > > > line instead of > > > > > > gnuradio-companion (e.g. ./top\_block > > > > > > out.txt) > > > > > > after you have generated the > > > > > > flowgraph. The gnuradio-companion > > > > > > cannot cope with big amount of > > > > > > data when the blocks gets out a lot > > > > > > of text. > > > > > > > > > > > > Bogdan > > > > > > > > > > > > On Monday, March 31, 2014 > > > > > > 1:22 PM, Nasi \< [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) \> > > > > > > wrote: Hi all, > > > > > > > > > > > > I am using ubuntu 13.04, > > > > > > GNURADIO 3.7. I cannot transmit or > > > > > > receive using two (USRPN200 ``` + XCRV2450 d.board+VERT2450 antennas) ``` > > > > > > devices for DVB-T project. > > > > > > Here is the dvb-t project: > > > > > > [GitHub - BogdanDIA/gr-dvbt: DVB-T implementation in gnuradio · GitHub](https://github.com/BogdanDIA/gr-dvbt) > > > > > > > > > > > > It will be very helpful and > > > > > > appreciated if you help me. If > > > > > > someone tested it or can do > > > > > > it, please let me know. As far as I > > > > > > know someone tested it with > > > > > > N210 model. > > > > > > > > > > > > I think this failure is due > > > > > > to high noise/interference or smt. > > > > > > else. However I tested it > > > > > > already with all possible > > > > > > configurations. I also > > > > > > attach my .grc files.