Since August 2019, Malaysia free over-the-air television broadcasting has been switched from analogue to digital.
The good news is, nowadays most newer model of television has built-in DVB-T2 decoder to receive digital over-the-air TV channels.
If your house/condominium/apartment has an aerial wall socket that connects to the external aerial antenna of the building that looks like the one below, you can use a TV cable with male-to-female connectors to connect your TV with DVB-T2 decoder to the TV wall socket and receive the broadcasted digital TV channels.
Referring to the table below, if you are staying in a highrise building, the cable buried inside the call connecting the wall socket to the external antenna should be coaxial cable of type RG11/U.
If you are staying in landed property which the distance between the external antenna and the wall socket is below 225 meters, then maybe RG6/U cable still be used without much problem.
For the portion of cable connecting your TV to the wall socket, RG6/U cable is recommended. Using RG11/U cable is even better, but its cost will be higher too.
If you are using RG59/U cable but don't face any problem with your TV, then you can continue using it, otherwise, consider upgrade the cable to RG6/U.
In the photo below, the black cable is type RG59/U and the white cable is type RG6/U. You can easily notice that the RG6/U has a much thicker diameter than RG59/U.
If your TV problem persists despite using RG6/U cable, you might probably need to resort to other solution, such as adding a signal booster, using digital TV decoder box, or receiving the TV signal using an internal antenna.