As an access point, the FritzBox can improve the WLAN of another router. Depending on the model, it can even be used as a repeater..
A FritzBox can solve problems with the WiFi reception of an old modem quite easily by inserting it behind the free router and laying it by cable in such a way that it can optimally set up the WiFi. To do this, the FritzBox must run in the so-called access point mode. Alternatively, the FritzBox can also expand an existing WLAN, then it serves as a so-called repeater.
To set up a FritzBox as an access point, it should first be reset to the factory settings. This is important to rule out errors in the configuration of the access point. Then you can start with the actual configuration:
If you already have a FritzBox with WLAN and cannot pull a cable, you can use the additional FritzBox as a repeater. The setup is child's play - especially if the FritzBox has already been set up normally or as a WLAN access point. Repeaters "extend" the WLAN by connecting themselves to it and also opening up a WLAN at the same time.