I have a TS832 audio-video transmitter, and in its datasheet it says that the operating voltage is typically 12V, but can range from 7V to 16V. I am powering the transmitter with a 9V battery. I am measuring the voltage between its DC IN (+) and its DC OUT (-) pins, and it's 5.1V. Shouldn't that be the same with the battery's voltage? There's nothing but cable between the pins and the battery terminals!
If I ignore this problem and connect everything else correctly (camera, receiver, antennas) and connect the receiver to a television, I see nothing. That's why I believe that this problem is why the whole system isn't working.
The transmitter also heats up quite quickly while it's operating, if that helps.