P-115 Signal Recorder and Data Analysis Program: Results

I have reached the point where I can test my program on real signals that I have picked up from a radio transmitter I build with an Arduino.

I tuned the radio to 89.62 Mhz, and recorded two signals: One with the antenna disconnected (which should be picking up almost entirely background noise) and another with the antenna connected (and a radio station clearly audible over the speaker).

I created a graph of the orginal signal after the window function was applied, the real and imaginary components, the magnitude, and a waterfall display for both the background signal and the tuned radio signal.

The waterfall graph isn’t full because I didn’t capture the signal for long enough, and there weren’t enough data points.

The following are the graphs of the background noise:

These graphs are of the radio signal:

There is a clear difference in the two signals. The second signal has a pattern that seems to contain human speech, which is visible in all of the FFT graphs. This, I feel, is a proof of concept of the system. The waterfall display also looks different, but it is hard to tell, since there is alot of noise also producing traces. It is possible some of the signal was picked up by the radio receiver even with no antenna. Even so, I think this system performed quite well, and it shows promise.