Video interference and damage siamese cable

Hi! I'm new in this forum and also it is my first time that I have installed a Camara System. I have two problems:

First: I have installed siamese cable through the pipe of my building. When I connect the camera, the video cable is not transmitting. Can I use a video baluns to transmit the video to the DVR through power cables.

Second: I am having interference in a camera that is connected to two cables Siamese Reame Coaxial Cable. I am using a BNC MALE TWIST-ON CONNECTOR to connect both cable and a BNC DOUBLE FEMALE ADAPTOR. Could this be the problem. How can I fix this problem? Also, we're very near T-Mobile antenna tower. Could this be the problem?