Dataset Open Access

December 2021 Eclipse Festival of Frequency Measurment IQ recording by station EA4GPZ

Estévez, Daniel

This dataset contains the IQ recordings done by the station EA4GPZ (Daniel Estévez), in Madrid (Spain), during the HamSci December 2021 Eclipse Festival of Frequency Measurment. The dataset contains 200 sps IQ data for WWV at 5, 10 and 15 MHz, and RWM at 4.996, 9.996 and 14.996 MHz. Each of the six frequencies is in a separate file. Additionally, the full recording span of 10 days is divided into 3 segments, since recording was briefly interrupted twice for technical reasons.

These recordings have been done with a Hermes-Lite2 beta2 DDC/DUC HF SDR transceiver connected to a random wire antenna, which is an end-fed wire of approximately 17 metres length set up as a sloper. The Hermes-Lite2 used a 10 MHz external reference coming from a Vectron MD-011 GPSDO. The generation of the sample clock and its divisions are exact factors with respect to the 10 MHz reference, so the sample rate of these files is exactly 200 sps locked to the GPSDO.

The LO of the DDC is not exactly set to the nominal frequency, so the following mHz scale frequency errors are present:

  • 4996 and 5000 kHz: 1/3*2^(-32)*76.8e6 Hz (approximately 5.96 mHz).
  • 9996 and 10000 kHz: -1/3*2^(-32)*76.8e6 Hz (approximately -5.96 mHz).
  • 14996 and 15000 kHz: no frequency error

The sign convention of these is that the frequency errors listed above should be added to the frequencies measured from the 200 sps IQ data in order to get the correct frequency. For more information about these frequency errors, see this post by the author.

The timestamps of the files are only accurate to a fraction of a second, since they are generated on the computer performing the recording and are not synced in any manner to the GPSDO. It should be possible to assess the accuracy of the timestamps by using the time signals in the recordings.

The recordings were made using GNU Radio 3.8 and gr-hermeslite2. Three FPGA receivers on the Hermes-Lite2 were tuned to 5, 10 and 15 MHz using an IQ sample rate of 48 ksps on each receiver. The IQ data was first decimated by a factor of 4 with a low-pass FIR filter. For the WWV channels, the output of this filter was decimated by a factor of 60 with another low-pass FIR filter. For the RWM channels, the output of the downsample by 4 filter was multiplied by a complex exponential with a frequency of 4 kHz (generated as a periodic vector to avoid any rounding off errors in its frequency) and then decimated by a factor of 60 with a low-pass FIR filter. Data was recorded to 16 bit integer raw IQ files and then converted to SigMF format.

The Hermes-Lite2 was set to an LNA gain of 18 dB throughout the recording, and a digital gain factor of 500 was used in the GNU Radio flowgraph to better adjust the signal amplitude to the range offered by the 16 bit IQ output files. The amplitude scale of this receiver system has not been calibrated to an absolute reference.

Warning: Between the third and second recording segment (i.e., starting at 2021-12-08T12:57:25) there was a power outage that rebooted the Hermes-Lite2 and the GPSDO. Due to operator mistake, the external reference of the Hermes-Lite2 was not enabled after the power outage. Therfore, in the thrid segment, the Hermes-Lite2 is running with its onboard TCXO. This segment should be used carefully for frequency mesaurement. In principle it could be possible to correct the frequency error, because the GPSDO 10 MHz signal leaks into the recording of WWV at 10 MHz.

Files (4.8 GB)
Name Size
ea4gpz_eclipse_festival_10000kHz_2021-11-29T18:33:48.932680.sigmf-data
md5:198403bf240f5ed2b251fa93979eea91
78.9 MB Download
ea4gpz_eclipse_festival_10000kHz_2021-11-29T18:33:48.932680.sigmf-meta
md5:ffd15c8a1561b3f7040bd4636c36b5f0
884 Bytes Download
ea4gpz_eclipse_festival_10000kHz_2021-11-30T22:00:01.018948.sigmf-data
md5:d04b7db690561d6042776636347af155
253.6 MB Download
ea4gpz_eclipse_festival_10000kHz_2021-11-30T22:00:01.018948.sigmf-meta
md5:fc5e0c4e6b909018fd554436e6760db7
884 Bytes Download
ea4gpz_eclipse_festival_10000kHz_2021-12-04T14:25:42.876005.sigmf-data
md5:52ed7b021a8be1b38c7379023874121e
272.1 MB Download
ea4gpz_eclipse_festival_10000kHz_2021-12-04T14:25:42.876005.sigmf-meta
md5:8c87165169945eaba016300026740f16
884 Bytes Download
ea4gpz_eclipse_festival_10000kHz_2021-12-08T12:57:25.367007.sigmf-data
md5:cd9b60ef046eef3cc6c5a3aae82f5c4b
194.8 MB Download
ea4gpz_eclipse_festival_10000kHz_2021-12-08T12:57:25.367007.sigmf-meta
md5:8187a43b28d799b05d0d9e4abcc28c81
884 Bytes Download
ea4gpz_eclipse_festival_14996kHz_2021-11-29T18:33:48.929313.sigmf-data
md5:a9cf5930887268a2e0d27ff9b7cba480
78.9 MB Download
ea4gpz_eclipse_festival_14996kHz_2021-11-29T18:33:48.929313.sigmf-meta
md5:5cdb303cbb26e4da38b9d5b7cc951080
884 Bytes Download
ea4gpz_eclipse_festival_14996kHz_2021-11-30T22:00:01.017652.sigmf-data
md5:24c1673950e3633254e2c14ff22df8e7
253.6 MB Download
ea4gpz_eclipse_festival_14996kHz_2021-11-30T22:00:01.017652.sigmf-meta
md5:90f928fa1ff3ff0d762b5a44a9453e0d
884 Bytes Download
ea4gpz_eclipse_festival_14996kHz_2021-12-04T14:25:42.875507.sigmf-data
md5:c5f773749620c591e6c43a73ae7e0b17
272.1 MB Download
ea4gpz_eclipse_festival_14996kHz_2021-12-04T14:25:42.875507.sigmf-meta
md5:e5d7034a9e8c0cc73f79e4dbc0f34766
884 Bytes Download
ea4gpz_eclipse_festival_14996kHz_2021-12-08T12:57:25.364330.sigmf-data
md5:3704ea08eb85906ed5329192b0bf7274
194.8 MB Download
ea4gpz_eclipse_festival_14996kHz_2021-12-08T12:57:25.364330.sigmf-meta
md5:e81b19f39ba4a50ac3ea529b3e686db4
884 Bytes Download
ea4gpz_eclipse_festival_15000kHz_2021-11-29T18:33:48.932537.sigmf-data
md5:3255e2bc9c153db7b7d9a350c98176a4
78.9 MB Download
ea4gpz_eclipse_festival_15000kHz_2021-11-29T18:33:48.932537.sigmf-meta
md5:f64aa31ead7ecb72e78b5dc4403643c0
884 Bytes Download
ea4gpz_eclipse_festival_15000kHz_2021-11-30T22:00:01.018020.sigmf-data
md5:35ac393f2a7996590c45b5d42d820f60
253.6 MB Download
ea4gpz_eclipse_festival_15000kHz_2021-11-30T22:00:01.018020.sigmf-meta
md5:d714d285f44bc658a19aa73d4568efaf
884 Bytes Download
ea4gpz_eclipse_festival_15000kHz_2021-12-04T14:25:42.875933.sigmf-data
md5:9442f72bcad3b4d22748d8ed81626606
272.1 MB Download
ea4gpz_eclipse_festival_15000kHz_2021-12-04T14:25:42.875933.sigmf-meta
md5:813a32111ef2633e6ef38f7eb2684d59
884 Bytes Download
ea4gpz_eclipse_festival_15000kHz_2021-12-08T12:57:25.366932.sigmf-data
md5:bf5a4f1fc8479d71694576cb8cf48d2f
194.8 MB Download
ea4gpz_eclipse_festival_15000kHz_2021-12-08T12:57:25.366932.sigmf-meta
md5:26b47d8135a40de5d391b89c94c24d0a
884 Bytes Download
ea4gpz_eclipse_festival_4996kHz_2021-11-29T18:33:48.931833.sigmf-data
md5:55f43551790ffd92d08660e3bcb97095
78.9 MB Download
ea4gpz_eclipse_festival_4996kHz_2021-11-29T18:33:48.931833.sigmf-meta
md5:fde1320be04767be7945c8d57fd004f3
883 Bytes Download
ea4gpz_eclipse_festival_4996kHz_2021-11-30T22:00:01.017942.sigmf-data
md5:28bb4b5f1340a769555b2bad025b92d9
253.6 MB Download
ea4gpz_eclipse_festival_4996kHz_2021-11-30T22:00:01.017942.sigmf-meta
md5:9e54ae3fb0a608eb1a39356de4c48e39
883 Bytes Download
ea4gpz_eclipse_festival_4996kHz_2021-12-04T14:25:42.875842.sigmf-data
md5:7bee300dc5864834b04962bb71fa4849
272.1 MB Download
ea4gpz_eclipse_festival_4996kHz_2021-12-04T14:25:42.875842.sigmf-meta
md5:e27a3cde35490a0c32ec757ce36990c8
883 Bytes Download
ea4gpz_eclipse_festival_4996kHz_2021-12-08T12:57:25.366836.sigmf-data
md5:50c71fe62420bb79e01ddec001de7bfa
194.8 MB Download
ea4gpz_eclipse_festival_4996kHz_2021-12-08T12:57:25.366836.sigmf-meta
md5:8d191cd60e794da5f421aad7377804ca
883 Bytes Download
ea4gpz_eclipse_festival_5000kHz_2021-11-29T18:33:48.932850.sigmf-data
md5:d926435cd9b59f93b9542aa0fa6759c1
78.9 MB Download
ea4gpz_eclipse_festival_5000kHz_2021-11-29T18:33:48.932850.sigmf-meta
md5:2cfa9e8a6c6fadd6de5af9d453e3fbb6
883 Bytes Download
ea4gpz_eclipse_festival_5000kHz_2021-11-30T22:00:01.019060.sigmf-data
md5:a01cadf2092749c5b82887a5263d3fed
253.6 MB Download
ea4gpz_eclipse_festival_5000kHz_2021-11-30T22:00:01.019060.sigmf-meta
md5:5e20c5c2bc1dae5679da01849649bf91
883 Bytes Download
ea4gpz_eclipse_festival_5000kHz_2021-12-04T14:25:42.876094.sigmf-data
md5:2b90ecee221110c47c524f4e01d4070a
272.1 MB Download
ea4gpz_eclipse_festival_5000kHz_2021-12-04T14:25:42.876094.sigmf-meta
md5:c5d8f89d2217c3e7ecdda71811c92c20
883 Bytes Download
ea4gpz_eclipse_festival_5000kHz_2021-12-08T12:57:25.367080.sigmf-data
md5:c1e38357ad6d41423eeaba3f7f5e59c2
194.8 MB Download
ea4gpz_eclipse_festival_5000kHz_2021-12-08T12:57:25.367080.sigmf-meta
md5:42e7267bf8734269f53df778e5835477
883 Bytes Download
ea4gpz_eclipse_festival_9996kHz_2021-11-29T18:33:48.931665.sigmf-data
md5:f8a60d914b6979f187d2656c30aa238c
78.9 MB Download
ea4gpz_eclipse_festival_9996kHz_2021-11-29T18:33:48.931665.sigmf-meta
md5:82b509829dae9c6d1fa837c9f12b5467
883 Bytes Download
ea4gpz_eclipse_festival_9996kHz_2021-11-30T22:00:01.017859.sigmf-data
md5:8ef0f0b943ebca9398a0463610c4e576
253.6 MB Download
ea4gpz_eclipse_festival_9996kHz_2021-11-30T22:00:01.017859.sigmf-meta
md5:c3f3956bc0e6888c80cdc2aa979c1827
883 Bytes Download
ea4gpz_eclipse_festival_9996kHz_2021-12-04T14:25:42.875720.sigmf-data
md5:7fc47b813f589ef846e009f3d31d66b3
272.1 MB Download
ea4gpz_eclipse_festival_9996kHz_2021-12-04T14:25:42.875720.sigmf-meta
md5:9301a978ba6f76a400f3dd82d7c09063
883 Bytes Download
ea4gpz_eclipse_festival_9996kHz_2021-12-08T12:57:25.366730.sigmf-data
md5:c2e659e1b2b739b435b5fe4c50daa695
194.8 MB Download
ea4gpz_eclipse_festival_9996kHz_2021-12-08T12:57:25.366730.sigmf-meta
md5:9b2b0508d5378724c2b3c9c14ed83bfb
883 Bytes Download
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