The coax cable that is used for satellite or cable TV, or a standard “over the air” TV antenna is not compatible with the repeater.
The coax used for cable and satellite RV is 75 ohm which is typically a “receive only cable”. The coax supplied with the repeater kit is 50 ohm which is a transmit and receive type cable.
There are major differences in the internal construction of Cable TV (75 ohm) coax and WiFi (50 ohm) coax. The two types are not compatible. Even if you are able to find the right adapters to connect everything up, cable TV type coax will not pass WiFi signals properly and you will have very poor performance if it even works at all.