Saturday, November 22, 2014

Rolling Noise Floor Tests Multiple Bands

So I've been talking about creating a system that I can drive around with in my truck and measure the Noise Floor on several frequencies at the same time.  In order to track down local sources of Power Line Noise and identify power poles that need some attention by the local power company "Ameren UE".

See previous blog posts here to get details leading up to todays 'stationary test of multiple frequencies running simultaneously".

In this test I'm using the Beaglebone Black, 4 RTL dongle receivers, 1 antenna shared by all 4 dongles, and a small web-app that runs on the Beaglebone which I've been working on this past week.

For a simulated noise source I create a gnuradio flow-graph that generates CW (morse code) on the 4 bands I'm interested in testing today.  The transmitter being used for this test is a 32 milliwatt HackRF One transmitting into a 10db attenuator at fairly low power to protect the RTL receivers.

In the video I hope to show the Web App I've called "Driveby".  Which is doing all of the monitoring of the GPS, reception data from the 4 RTL dongles, as well as REAL TIME graphing of all the data and REAL TIME mapping of the data based on the GPS coordinates.  You will see the web-app "Driveby" running live, as well as the GNURADIO Flow Graph running and I will be changing the frequency it's transmitting on by selecting various radio buttons on the GNURADIO app.  

Don't get confused.  The GNURADIO app and HackRF One are simply being used to generate RF noise.  They won't be part of the actual Drive Testing I will be doing.  This is just being used to simulate noise in order to test the Beaglbone Black Web application I've created.

Video is uploading now and I'll update this blog post with that shortly.