Disconnecting the power from most amplified antennas does not disconnect the amplifier. Instead it makes the amplifier a block to signals.
The high powered stations are less than a mile from you. The signals are far too strong for an amplifier to operate correctly. All consumer TV amplifier products are going to be overloaded.
Try a Terk HDTVi
http://www.walmart.com/ip/Terk-Passi...ndingMethod=rr But, you may also need one or two 20 dB attenuators.
http://www.amazon.com/F-Male-Attenua...b+F+attenuator
I'm quite certain a straightened paper clip will be enough antenna to give you many signals. If you try this, don't push the wire into the TV antenna connector more than 3/8". I'm not recommending you do this, just illustrating the extreme nature of your situation.