Radar, interrupted FMCW, 6985 and 4945 kHz, March 11, 2014, 0145 UTC

This is an unusual radar waveform, I have not seen it used on HF before. The basics are that it is about a 21 kHz wide FMCW with a repetition rate of about 78 Hz, resulting in a chirp rate of about 1.638 MHz / sec. However right in the middle of each sweep is a gap of about 1.5 kHz and around this gap the sweep is non-linear, as can be seen in the still images I included. I have only seen this waveform used one day, on two frequencies, first 6985 kHz and shifting from that frequency to 4945 kHz. Propagation at that time of day supports the source as being in the Americas. A DF cut was not taken.

Видео Radar, interrupted FMCW, 6985 and 4945 kHz, March 11, 2014, 0145 UTC автора Китайские машины - путешествие через культуру