Yes, you can couple two cables. Unfortunately, you may not have enough signal left by the time the signal gets to the antenna.
As the signal is attenuates through the cable, it approaches the noise floor. At some point, even the gain of an excellent antenna is not going to amplify the signal enough to make much of a difference.
The gain of the antenna relates to the signal you give the antenna ... if there isn't much signal, you aren't going to get much of a signal out.
FWIW
Scott
