Recordings of past presentations are available at the twitch.tv link below.
DEFCON 28 (a well-known hacker conference) is online this year and is FREE to attend online and view presentations. Of particular interest will be Ham Radio Village. Several talks and presentations related ham radio will be available. Ham Radio Village will use the Twitch platform for their presentations. https://www.twitch.tv/hamradiovillage/ No login is needed to view these presentations (live or recorded).
Some other DEFCON sessions, i.e. Aerospace Village (interesting stuff about satellites, etc.), will be held live and also recorded for later viewing. Some have already been recorded and are available immediately via YouTube.
The event is over. Info above for recorded sessions will still be valid.
Visit https://defcon.org/ for more information and for links to join and attend.
Note: If you are not familiar with Discord, joining the sessions can be confusing. Read the instructions carefully and follow exactly! If you get stuck, email the editor and put "DEFCON" in the subject line. I'll try to help if I am available, i.e. via phone, radio, or Zoom.