Ionosonde Development Resources University of Twente SDR Chirp Ionosonde Page Separation of O/X Polarization Modes on Oblique Ionospheric Soundings (Harris et al., 2017) Works by Juha Vierinen Google Scholar Page Github Page GNU Chirp Sounder Page Oblique Ionograms Between Sodankyla and Longyearbyen (Including link to Version 1.25 of GNU Chirp Sounder code) Works by Tom McDermott N5EG TAPR DCC 2015 Sounder Presentation TAPR DCC 2015 Sounder Paper