Replication Data for: "Tracking Traveling Ionospheric Disturbances through Doppler-shifted AM radio transmissions"

Each file in this data set is a tarred directory of files, corresponding to the receiver location, date, and UT start time in the filename.

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For example, the data set labeled hanover_amd_14.12.20_21:00:02.tgz contains data from the Hanover, New Hampshire, receiver on Dec 14, 2020, starting at 2100 UT.

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To extract the data begin by unpacking the file, e.g. through
tar -xvf amd_14.12.20_21:00:02.tgz

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The result will be a directory labeled with start date and UT (but not site identification).

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14.12.20_21:00:02

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In the upper directory are three files and a subdirectory.

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file collect.sh is the script used to collect the data

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file hostname tells which receiving site as amd2 to amd7, decoded using this table:
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RX Location Latitude Longitude Elev
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AMD2 Hanover, NH 43.7054033 -72.2864367 187.8
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AMD3 Schenectady, NY 42.8127017 -73.9116233 118.2
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AMD4 Jenny Jump, NJ 40.9073717 -74.9254683 319.2
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AMD5 New Bedford, MA 41.5949650 -70.9102633 17.6
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AMD6 Ithaca, NY 42.4955650 -76.4310283 344.3
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AMD7 Massena, NY 44.9243267 -74.8975733 77.0

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Directory FFT contains approximately 100 data files. The name of each file encodes the start date and time, and the frequency range, for example:

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14.12.20_21:00:02_1MSs.4425.2673-3209

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The frequency range is encoded in two pieces. The first number, 4425 in the example above, corresponds to the bin number of the first 8192 FFT. The second gives the range of bin numbers of the second 8192 FFT, inclusive of end points. The number of frequency bins is therefore 537. The sample rate is 1 MHz, and the frequency range is offset by 600 kHz (so that 600-1600 kHz are measured). To calculate the frequency in kHz, take 600+( ((first_number -1)*8192 + second_number)/8192^2))*1000). Using the first of the second numbers gives the bottom of the frequency range; using the second gives the top. The frequency range is about 8 Hz (around a selected AM carrier frequency).

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The data are packed in consecutive 2-byte unsigned integers, unpacked for example using

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od -v -t u2 -w2 -A n datafile

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The result will be a string of ASCII numbers representing the relative power spectral density in each of 537 frequency bins, followed by another 537, another 537, etc. (The total number of lines should be an integer times 537.)

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The cadence for each set of 537 power spectral densities is 33.554432 s. That is, the first set of 537 power spectral densities corresponds to the start time given in the file name, 21:00:02 in this case. (The center time of the analysis therefore corresponds to this time plus 16.777216 seconds.)