Polarization analysis of HF over-the-horizon radar signals

[David Lonard]

Hello everyone,

I have been playing around with the analysis of some HF radar signals with my LimeSDR that I thought I would share with you. Using the two coherent channels on the LimeSDR I've oriented two magnetic loop antennas in orthogonal polarizations to analyze ordinary and extraordinary wave HF signal propagation through the ionosphere at 8 to 18 MHz.

Many OTH FMCW signals of opportunity exist at HF frequencies and I wrote some code to automatically pull these signals out of a sea of other signals and RFI to analyze them. So far, I've only analyzed a few FMCW bursts from these frequency agile radars, but here are some preliminary findings.

I assume that meteor scatter detections could be analyzed using these signals and perhaps other ionospheric phenomenon as well at millisecond time resolutions.

David

[David Lonard]

Here is some more analysis of the evolution of phase angles of FMCW pulses from pulse to pulse. It appears to be showing the movement of distinct objects. Next challenge will be to find ways to automate the analysis of these signals since this data comes from only a single FMCW OTH pulse train of 1 second.