This is very similar to Question 326211, but in this case, the LAN is an unstable Wi-Fi connection.

I need to transfer about 11 GiB of files between two computers, both running Linux (although one may be rebooted into Windows.) Their connection is both slow and unstable (due to Linux's awful Wi-Fi support,) but removable media (such as a flash drive or external hard drive) is not an option at this time.

Right now, I'm slowly transferring the files, one by one, across SFTP, but I have to reconnect each computer approximately every 90 seconds, and the computers are not very close to each other, so this is not feasible.

This is not a duplicate of Question 30186; that one specifically concerns Windows 7, and all the proposed solutions involve closed-source, Windows-only programs (which are all spyware IMHO, and are all off the table even if I trusted them - one of the computers is Linux-only.)