Raw Data Files

The raw data analysed for the ZRO test described in this article were recorded from Oscar 13 at 144 MHz on 24 April 1993. The data were recorded using a clone Sound Blaster sound card at a 4 kHz sample rate, in 8-bit samples, and written in the .VOC sound file format popularized by Creative Labs. This format is described in several popular texts, for example "Sound Blaster, The Official Book" written by Ridge, Golden, Luk & Sindorf, published by Osborne/McGraw Hill.

The data file contains about 6 minutes of continuous data, starting with ZRO level 8 signals (24 dB below the satellite beacon), including also the level 9 (-27 dB) and level A (-30 dB) signals. The data were recorded continuously, giving a total duration of about 6 minutes. At the end of the level A signal, there is an "End of test" message transmitted at full power (0 dB with respect to the satellite beacon.).

It is possible to decode occasional CW characters of the level 8 data by ear. I can detect the presence of some level 9 signal, but I cannot decode any characters reliably by ear. By ear, I am not able to detect even the presence of any signal during the level A transmission, although the DSP processing described in the article (QEX, Jan 1994) was able to give 100% error-free copy.

As well as the raw data files, grey-scale and false-color plot are available from an analysis of the entire level-A transmission, with the end of the stronger level-9 signal appearing at the beginning.

Below are links to the same recording of raw data, made available in .VOC or .WAV format, with or without PKZIP compression.

This .ZIP file contains, in addition to the raw .VOC file, a greyscale and false colour image of the level-A signal processed from the .VOC file, with a short read-me file.

Explanation of the AMSAT ZRO tests.

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