50 MHz elliptical polarization study

[David Lonard]

Hello everyone,

As a side project, I've been interested in using the 2x2 MIMO capability of the LimeSDR to analyze HF and VHF propagation. HF/VHF propagation through the ionosphere can be complex, with received signals arriving as elliptically polarized signals with ordinary and extraordinary wavefronts arriving at a receiving antenna. 

With an orthogonally polarized antenna like the ones used by LOFAR and LWA, one can measure the received signal's angle of arrival in two dimensions so I set up a pair of inverted V antennas to receive 6 meter band FT8 signals. 

A band opening occurred during my observations, so I had many signals to look at. A statistical analysis of these signals might be interesting to do. I've seen unusual propagation on 6 meters at various times as an amateur radio operator, so I think some longer-term observations might turn up some unexpected results in the future. With some more work, it would also be possible to decode and map out all the FT8 transmitters to relate the signals to their geographic distribution.

I did some meteor scatter runs at 54.309 MHz also and it looks like meteor scatter could be interesting to analyze in terms of polarimetry as well.

David