getting pg_basebackup to use remote destination

I thought I knew how to do this, but I apparently don't. I have to set up a
new server as a standby for a PG 11.1 server. The main server has a lot
more resources than the standby. What I want to do is run pg_basebackup on
the main server with the output going to the data directory on the new
server. But when I give this command:

pg_basebackup -D "ssh root(at)10(dot)0(dot)1(dot)16:/mnt/dbraid/data" -P -v -X s

it instead writes to my root drive which doesn't have the space, so it
fails and deletes the partial backup.

While I think I could figure out how to backup to a local directory then
rsync it to the new server, I'd like to avoid that due to the 750GB size.

Is there a way to tell pg_basebackup to use a remote destination for
output? Or do I have to run pg_basebackup on the standby server?

And while I'm asking, has anyone yet written a guide/tutorial for PG 11
replication? Everything I find online is very old.

Chuck Martin
Avondale Software