@skylinekiller 

I don't think you can?

Well, I think there could be a way, but you don't need a router for that, at least with Windows.

Don't need that either if you phone has 'hot spot' capability? That said, when I go places where I have to wait, I take my iPhone and iPad with me. If they don't have wireless available I turn on the iPhone's Hotspot and connect the iPad to it. All I can say, compared to normal wireless anywhere, it is painfully slow. It is a 5G connected phone no less by my carrier, T-Mobile it seems doesn't give it full speed via a Hotspot. I wouldn't imagine it would work feeding a router to many devices with it would be much better?

Router's all require a WAN connection from your ISP, via a device that handles the input and outputs WAN to be used. I don't know of anything that does that via a wireless connection to a phone or Cell Carrier (other than the ones they sell, like T-Mobile).

Most carriers probably also sell Mobile Hotspots, and they are basically a router. I do think you can feed that into a router, but it would only duplicate the Hotspot function in most cases?

I may be wrong about feeding the router the signal from a phone, others might know better than mee? See if you get a different answer? I'd be interested too if/when the ISP signal is lost.

  @IrvSp Thank you.  Yeah I know it is slow, I just want to use it to update the Plex server from time to time.  PArents in the country and only use cell service on their laptop as the internet.  I want to build a PLex server using a router and TV, but occasionally, update covers and stuff, not for heavy use.  I am surprised with all the tech out there this isn't possible.  Or at least have the router receive the wifi signal and re-transmit as the source..

skylinekiller wrote

  I am surprised with all the tech out there this isn't possible.  Or at least have the router receive the wifi signal and re-transmit as the source..

  @skylinekiller 

These TP-Link links might interest you:

https://www.tp-link.com/us/support/faq/2032/

https://www.tp-link.com/us/support/faq/1325/

https://community.tp-link.com/en/home/stories/detail/468

Different h/w though.