NO! Do not connect another antenna to the power brick.  

The ClearPix technology that was designed to improve reception the brick actually sends current up and into the antenna which allows the antenna to respond to over-the-air signals and adjust to them in real-time, automatically improving image reception.  Using an antenna other than the one (pictured below with the green check) that is included in the AirWave packaging will result in damage to the antenna (voiding the warranty).