No, the UniFi Mobile Router Industrial (UMR-Industrial) is primarily designed as an LTE Cat 4 mobile WiFi router and not as a WiFi amplifier or repeater. It does offer WiFi functions, but its main function is to provide Internet access via LTE and not to amplify an existing WiFi signal. If you only want to boost the existing Wi-Fi signal outdoors, a dedicated Wi-Fi range extender or repeater would be a better choice.

You can connect an access point (AP) indoors using an ethernet cable.

According to my research and the manufacturer's specifications, it can be operated locally, but with restrictions. This means, of course, without an internet connection and VPN.

The device has a Wi-Fi antenna and an RJ45 port. So that's enough to connect devices

Ne only a data SIM

I cannot see the geoposition on the local interface of my UMR. Logging in with SSH to search for information on the geoposition with the CLI is also not possible ("Connection refused"). I can only see the geoposition in the mobile routing portal (cloud). Setting up a VPN from the UMR to the UDM works. Using the mobile routing portal makes the setup very easy. It should also work without the mobile routing portal, but it is more complicated. I have not tried that. Yes, you can access the local interface from the home network via VPN.

Yes, the umr has a 4-pin ATX-DC connector that accepts input voltages from 9-30V

Because you also lose mobile phone signal power with antenna extension cables, you should not use them (the two outer antennas are mobile phones (LTE), the middle one GPS). It is better to place the router in a location where the mobile network is good and use a long network cable. This can also be used to supply the router with PoE so that no power supply unit is required at the router's location. The router also has two WLAN antennas on the lower side. The positioning may not be so good for Wi-Fi reception. But you can also switch off the WLAN on the UMR and connect another WLAN access point in the living area. I would rather do it this way, but in principle you can of course also place the LTE antennas with long cables. I don't know how much additional signal attenuation there is per metre of cable. It certainly depends on the quality of the cable. Connections of the UMR Industrial: https://techspecs.ui.com/unifi...

According to our research, this article can do the following: The UniFi Mobile Router Industrial (UMR-Industrial) is a compact and robust LTE Cat 4 mobile Wi-Fi router for versatile indoor and outdoor IoT applications. Thanks to its network-independent function, it ensures seamless connectivity across different networks. This robust router features advanced site-to-site VPN and VPN client routing for secure communication between remote locations. Equipped with two Gigabit Ethernet (GbE) ports and a PoE output, the UMR-Industrial can power other devices when equipped with a PoE+ input. Its flexibility in power supply options, including PoE, USB Type-C and a 4-pin DC socket, ensures uninterrupted operation in a wide range of environments. Designed for harsh conditions, the UMR-Industrial features outdoor GPS location tracking and flexible mounting options, making it ideal for installation on walls, poles and DIN rails. The device is weatherproof (IP66) with the included cover and offers reliable performance in exposed outdoor areas. For advanced functions, users can choose the Mobility Cloud subscription, which offers additional functions and services. Whether for industrial IoT applications or remote site management, the UniFi Mobile Router Industrial offers reliable connectivity and robust performance.