▸ Antenna Modeling with xnec2c: link

▸ We communicate by ionspheric reflection -- not refraction: 1.9 Mb pdf. These slides are adapted from a presentation given at the 2024 New Mexico TechFest.

▸ Doppler shift on meteor scatter pings: 451 kb pdf

▸ Meteor scatter with very short pings: 460 kb pdf. An earlier version of this paper was published in the 2020 Southeastern VHF Society Technical Journal.

▸ FSK441 vs MSK144 for meteor scatter communication at 222 MHz was the subject of a short presentation at the Central States VHF Society Annual Meeting in 2022.

▸ Synchronization in FT8: 452 kb pdf    This note is based on my attempt to reverse-engineer portions of the mostly undocumented Fortran open-source code. I did not have access to protocol design documentation and this paper has not been endorsed by the WSJT-X developers. Last revised 29 July 2019. This paper was presented at the 2019 TAPR Digital Communications Conference. A video recording of the talk is available on YouTube and at Ham Radio 2.0.

▸ Reflection from ionized meteor trails at 50 and 144 MHz: 83 kb pdf