[kb2fzq]

Here's an explaination of a balun:
A balun, is a type of electrical transformer that can convert electrical signals that are balanced about ground (differential flat twin lead cable, in our case 300 ohms) to signals that are unbalanced (single-ended coaxial cable, in our case 75 ohms) and vice versa. BAL-UN
The balun transforms the impedence of the TV signal that comes off the antenna, which is 300 ohms to 75 ohms, so that less lossy coaxial cable can be used to direct the signal to the TV. Twin lead can be effected by metal objects, and will have a degraded signal, as opposed to good quality coaxial cable.
All a balun does is convert one impedence to another impedence, and nothing more.
A balun will not allow direct current voltage to pass thru it, and should be connected right at the antenna, IF a factory installed, 75 ohm F-connector is not present on said antenna, which on some of the new antennas, the F-connector is present, in which case a balun would not be necessary.
In your case, you have a balun connected to the upper end of your coaxial cable, which is then attached to the pre-amp...that's a balun, but in your configuration, the balun stops the voltage from getting to the pre-amp, thus not powering the pre-amp, thus not allowing any of the TV signal to make it to your TV....this is why the suggestion was made to connect the balun on the end of the coax, directly to the antenna....