== Working with GNURadio and Nutaq ZeptoSDR ==

[[TOC(Tutorials/k0SDR*)]]

=== Description ===
This example will demonstrate how to use GRC (GNU Radio Companion) with [wiki:Hardware/fDevices/cSDR/hNutaq#NutaqZeptoSDR Nutaq's Zepto SDR].

=== Set up ===
 * Before you can access the testbed, you need to [https://www.orbit-lab.org/schedule make a reservation] and get it approved by the  [wiki:Documentation/Scheduler reservation service]. After receiving the reservation's confirmation (approval) email, load the ''ubuntu-14-04-64bit-sdr.ndz'' on two nodes and turn them on - one node with a Zepto SDR and the other node a USRP. For this example we'll use node20-13 and node20-20 which have a Zepto SDR and USRP, respectively:

 * [[CollapsibleStart(Login into reserved domain: ssh username@grid.orbit-lab.org)]][[Include(Documentation/Short/Login)]][[CollapsibleEnd]]
 * [[CollapsibleStart('Load an image on the nodes: omf load -i ubuntu-14-04-64bit-sdr.ndz -t [ [20,13],[20,20] ]')]] [[Include(Documentation/Short/LoadImage)]][[CollapsibleEnd]]
 * [[CollapsibleStart(Turn on the nodes: omf tell -a on -t [ [20,13],[20,20] ])]][[Include(Documentation/Short/TellOn)]][[CollapsibleEnd]]
Once the nodes boot up, verify that the interface to each SDR is configured correctly.

'''Verify connection to Zepto SDR:'''
{{{
ifconfig eth2 192.168.0.1 netmask 255.255.255.0 mtu 9000 up
ping 192.168.0.101
}}}

'''Verify connection to USRP:'''
{{{
ifconfig eth2 192.168.10.1 netmask 255.255.255.0 mtu 9000 up
ping 192.168.10.2
}}}

=== Run the GRC scripts ===

Download the receiver ''zepto_rx.grc'' into node20-13 and open it with GNU Radio Companion.
{{{
root@node20-13:~# cd /opt/Nutaq/ADP6/ADP_MicroTCA/sdk/gnuradio/gr-nutaq/examples
root@node20-13:/opt/Nutaq/ADP6/ADP_MicroTCA/sdk/gnuradio/gr-nutaq/examples# wget http://www.orbit-lab.org/raw-attachment/wiki/Tutorials/k0SDR/Tutorial10/zepto_rx.grc
root@node20-13:/opt/Nutaq/ADP6/ADP_MicroTCA/sdk/gnuradio/gr-nutaq/examples# cd ..
root@node20-13:/opt/Nutaq/ADP6/ADP_MicroTCA/sdk/gnuradio/gr-nutaq#sh launch_gnuradio_companion.sh &
}}}

A window should pop up similar to the following:
  || [[Image(zepto_rx.png, width=500px)]] ||


Next download the transmitting side ''usrp_tx.grc'' and open with GNU Radio Companion.
{{{
root@node20-20:~# wget http://www.orbit-lab.org/raw-attachment/wiki/Tutorials/k0SDR/Tutorial10/usrp_tx.grc
root@node20-20:~# gnuradio-companion
}}}

A window should pop up similar to the following:
  || [[Image(usrp_tx.png, width=500px)]] ||


On both GRC windows click on the execute (side ways triangular) button to start both scripts. On the receiver side and spectrum window should open showing a carrier frequency. The details of the center frequency, power, gain, etc are in the GRC files - tweak a some of the parameters and validate by observing the spectrum.