Help using RDP via a tether I run a PC which controls my astronomical telescope equipment, it works off batteries as there is no mains power at the site. There is mobile service at the site and I've successfully tethered my phone to the windows 10 PC via a USB cable tether, so I can get internet access using a browser on the PC.
I would like to use my PC at home to control the remote PC via its phone tether and I usually use Microsoft's Remote Desktop software to do this when connecting to PCs on a LAN or over the internet, but I can't seem to find the tethered PC's connection credentials. I'm probably missing something I guess.
I've searched for solutions on the internet such as ' how to rdp to a phone tethered PC', but not had any luck with that.
Could anyone explain how to use the remote desktop client to login to my tethered PC?
Many thanks for help.
The main problem of RDP is that you need a public IP address for directly establishing the RDP connection on port 3389.
In your case there are two obstacles which make it next to impossible:

Nearly all mobile data plans do not grant you a public IP address. Instead you are getting a private IP address from a carrier internal network. To access servers on the Internet this network uses carrier-grade-NAT (NAT on carrier side, this implies that you can not configure a port mapping as you can do on DSL home routers which also do NAT).
The main reason for most carriers (nowadays) is that they don't have enough public IPv4 addresses to assign every device an own. And mobile networks providing IPv6 services (und may be a public IPv6 address) may exists but I have not yet encounter one.
Some carriers allows communication within this private network, in such a case you could use a second cell phone for the RDP client and then connect to the carrier network internal IP address of RDP server. The problem is how to get this IP - regular dynDNS clients I know only give you the public IP.

For tethering the phone acts as NAT router, therefore even if you would manage to get direct access to the IP of the cell phone attached to the RDP server you would still need to forward the RDP port from the phone to the PC.