I use the Shotmarker electronic target system that operates on wifi at the address of 192.168.100.1. If I try to use it near my house the wifi will not connect my phone to this address. It will connect to my Starlink AP located at 192.168.1.1

I even uninstalled the Starlink AP but the Shotmarker will still not connect.

Any ideas on what I can do to fix this?

Is it a signal strength issue? If so probably the simplest thing to do is plug another wifi router into a spare port of your present router and run it to the wall nearest where you want your phone from outside connecting.