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Friday, October 7, 2016
SDR Screen Shots of Received Voice Transmissions
During this morning's QSO on 3740 kHz, Jim K4JPM shared his Flex Radio screen via Google Hangout. He had good reception of the lower sideband voice transmissions from W4BXI and W4UOA. The screen shots below show an abnormal property of each signal. Jim activated the peak mode on his receive display to hold the peak value at each frequency over a period of many seconds of voice transmission. The displays show a panadapter view (amplitude vs frequency) on top with a waterfall display (amplitude [brightness] vs frequency and time) below. The light-shaded box on the panadapter indicates the receiver's audio bandwidth setting. Signals outside of this box are not heard in the speakers.
W4BXI signal at K4JPM
Above is the view of W4BXI's signal on Jim's Flex Radio. Click on the image for a full-size view. The notable detail here is the presence of carrier at 3740 kHz (red vertical line). The LSB voice band shows the fairly typical male voice with more energy at the lower audio frequencies.
W4UOA signal at K4JPM
Above is the view of W4UOA's signal on Jim's Flex Radio. Click on the image for a full-size view. Note the presence of energy in the upper sidebands (to the right of the red line).