Here's the update.

I retried the NetGear card, re-created the profile, and tried again
with that. Works fine. So... I'm sure I make a mistake the first time
through somewhere with that. As for the built-in... from my previous
post, you can see that it's just plain weird. For now, I'm happy with
the NetGear card. My guess is that the built-in has something wrong
with it, or it's incompatible with my NetGear router.