Analysis of received audio

KB4PYR audio

In reference to Carl's audio recording, here are histograms of each station's initial transmission, as analyzed by Cool Edit 2000 software.


WA5MLF audio

KB4PYR's audio sounded like it had better signal-noise ratio, but it is hard to draw conclusions from the analysis since voice is a complex waveform and the stations have different hardware and different operator's voices. The presence of more lower-level content in WA5MLF's audio suggests that it may have more noise or maybe that it is not as strong, but the AGC action of the Tuscaloosa receiver may obscure the comparison.

FFT analysis shows some differences, but mostly in the low-frequency end of the spectrum. A better frequency analysis should be obtained by first doing a high-pass filter operation on the recorded audio file. I'll report on that later.