# Some problem with my USRP N210 **URL:** \ **Category:** GNU Radio\ **Created:** [October 9, 2014, 5:45pm UTC](https://www.ruby-forum.com/t/some-problem-with-my-usrp-n210/232444 "2014-10-09T17:45:56Z")\ **Posts on this page:** 5\ **Page:** 1
**Author:** ![addis\_a](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/c4cdca/32.png) [@addis\_a](https://www.ruby-forum.com/u/addis_a)\ **Post date:** [October 9, 2014, 5:45pm UTC](https://www.ruby-forum.com/t/some-problem-with-my-usrp-n210/232444/1 "2014-10-09T17:45:56Z")
Hi everyone, I am a new user of GNU radio. I am trying to communicate between Tmote Sky sensor node and USRP N210. I use the Tmote Sky sensor node as transmitter to broadcast messages by flashing the example code into the node. The messages are broadcast in radio channel 26. (The code is this one “./contiki/examples/ipv6/simple-udp-rpl/broadcast-example.c”) I use USRP N210 as the receiver. I just want to test whether my USRP can receive the broadcast messages or not. So I made a small receiver in gnuradio-companion which just has a USRP Source, a Scope Sink and an FFT Sink. I set the sample rate to be 4M, center frequency to be 2.48G, Channel gain to be 15dB. However, in the scope sink and fft sink, I cannot find any signal except the noise. I am sure the sender works successfully because I have a receiver implemented on another Tmote Sky sensor can receive the broadcast messages. I just want to make sure my USRP N210 can receive the signal so that I can make a 802.15.4 receiver on it in the next step. I hope someone could give me some suggestions that I can make it work. Thanks in advance, Su broadcast-example.c [http://gnuradio.4.n7.nabble.com/file/n50723/broadcast-example.c](http://gnuradio.4.n7.nabble.com/file/n50723/broadcast-example.c) top\_block.py [http://gnuradio.4.n7.nabble.com/file/n50723/top\_block.py](http://gnuradio.4.n7.nabble.com/file/n50723/top_block.py) Receiver.png [http://gnuradio.4.n7.nabble.com/file/n50723/Receiver.png](http://gnuradio.4.n7.nabble.com/file/n50723/Receiver.png) – View this message in context: [http://gnuradio.4.n7.nabble.com/Some-problem-with-my-USRP-N210-tp50723.html](http://gnuradio.4.n7.nabble.com/Some-problem-with-my-USRP-N210-tp50723.html) Sent from the GnuRadio mailing list archive at [Nabble.com](http://Nabble.com). ---
**Author:** ![liisuu](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/l/958977/32.png) [@liisuu](https://www.ruby-forum.com/u/liisuu)\ **Post date:** [October 9, 2014, 5:55pm UTC](https://www.ruby-forum.com/t/some-problem-with-my-usrp-n210/232444/2 "2014-10-09T17:55:17Z")
If there aren’t any GR-specific issues, you might consider moving this to the UHD-users mailing list. - Presumably, you’re using an SBX? - Is there any chance the bursts are just very short? Experiment with the trigger settings on the scope to see if you can catch any bursts. -John ---
**Author:** ![liisuu](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/l/958977/32.png) [@liisuu](https://www.ruby-forum.com/u/liisuu)\ **Post date:** [October 9, 2014, 7:59pm UTC](https://www.ruby-forum.com/t/some-problem-with-my-usrp-n210/232444/3 "2014-10-09T19:59:41Z")
Hi John, Thanks for your reply. I am using RFX2400 2.3-2.9GHZ RX/TX I increased the message length from 4 to 100 at the sender. But I still can not observe the signal. (Maybe because of the power of signal is too small?) The USRP N210 can receive signal at frequency around 2.9GHz. So I think the hardware of USRP still works. But I cannot make it work now. Thanks for your help. -Su – View this message in context: [http://gnuradio.4.n7.nabble.com/Some-problem-with-my-USRP-N210-tp50723p50726.html](http://gnuradio.4.n7.nabble.com/Some-problem-with-my-USRP-N210-tp50723p50726.html) Sent from the GnuRadio mailing list archive at [Nabble.com](http://Nabble.com). ---
**Author:** ![liisuu](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/l/958977/32.png) [@liisuu](https://www.ruby-forum.com/u/liisuu)\ **Post date:** [October 10, 2014, 4:20pm UTC](https://www.ruby-forum.com/t/some-problem-with-my-usrp-n210/232444/4 "2014-10-10T16:20:59Z")
Hi, On 10/09/2014 05:43 PM, liisuu wrote: > I use USRP N210 as the receiver. I just want to test whether my USRP can > receive the broadcast messages or not. So I made a small receiver in > gnuradio-companion which just has a USRP Source, a Scope Sink and an FFT > Sink. I set the sample rate to be 4M, center frequency to be 2.48G, Channel > gain to be 15dB. > > However, in the scope sink and fft sink, I cannot find any signal except the > noise. Maybe you want to try gr-fosphor [1]. AFIAK, it uses all samples to calculate the FFT, so it will be easier to spot the bursts. > I am sure the sender works successfully because I have a receiver > implemented on another Tmote Sky sensor can receive the broadcast messages. > > I just want to make sure my USRP N210 can receive the signal so that I can > make a 802.15.4 receiver on it in the next step. There is already a transceiver that is tested with TelosB motes [2]. It also implements parts of the Contiki RIME stack. Best, Bastian [1] [Making sure you're not a bot!](http://sdr.osmocom.org/trac/wiki/fosphor) [2] [GitHub - bastibl/gr-ieee802-15-4: IEEE 802.15.4 ZigBee Transceiver · GitHub](https://github.com/bastibl/gr-ieee802-15-4) ---
**Author:** ![liisuu](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/l/958977/32.png) [@liisuu](https://www.ruby-forum.com/u/liisuu)\ **Post date:** [October 9, 2014, 8:05pm UTC](https://www.ruby-forum.com/t/some-problem-with-my-usrp-n210/232444/5 "2014-10-09T20:05:31Z")
4 to 100? What are the units? How long is the actual burst? Just guessing - a ~100 byte packet at the lowest datarate (250 kbps) of the CC2420 chip means the packet will e about 3.2 ms. If you’re using the 2 mbps rate, obviously it’ll be much shorter. Unless you’re sending these packets with very high duty cycle, you won’t really see anything in the FFT sinks… Did you experiment with setting triggers in the scope like I suggested? -John