These are sample files for time of flight measurement. example_second.csv The file example_second.csv includes one second's worth of data taken at a 512 /s sampling rate. The file encompasses 512 samples spaced linearly in time throughout that second. Each of the 512 entries in the file is one sample of the audio voltage taken by a 10-bit A/D converter, with values from 0 to 1023 mapped linearly to the range of minimum to maximum measurable voltage: i.e., for an audio range of -1.5 to 1.5 volts, a value of 0 is equivalent to a value of -1.5V, a value of 512 is equivalent to 0V, and a value of 1023 is equivalent to a value of 1.5V. Second_ticks_20220908 This file contains one day's worth of ToF measurements. The date of recording is included in the filename. The metadata at the beginning of the file contains the receiving station callsign; the transmitter frequency; and the Maidenhead grid square of the receiving station. Each row of the .csv file contains the second tick measurements for one second of the UTC day. Only the first 24 ms after the start of the second are recorded. (At the location of the receiving station, AD8Y, used for these measurements, this is an adequate length of time to capture the second ticks; elsewhere, longer recording may be needed.) The values of each row then follow the same convention listed above. Ionospheric variability may be visualized by creating a heatmap of these values with a divergent colormap. Second_ticks_20221008 This file contains one day's worth of ToF measurements which show a coronal mass ejection.