After a bit more testing, I think you are correct that my issue is the repeater, when the signal isn’t very strong or has interference. When the signal to the AP is strong the repeater is working well, and if I use a wired connection on either side the connection is strong. When the AP signal is’t great (and/or when it auto-connects to a different AP), that is when the repeater side drops.

But, there is an odd component to this. Here is the scenario I’m seeing at the moment:

  1. Connected WISP to my own router, good stable repeater connection
  2. Connected WISP to my neighbor’s xfinity router, weak connection, unstable repeater
  3. Switched back to my router (1), seems like a good connection but keeps dropping
  4. After several minutes of instability, the connection seemed to become solid again

Maybe something about switching connections is causing problems for longer than I would expect? (several minutes after switching)