I stay just outside a highly secured defence area (inside where they use signal jammers) which makes it impossible for mobile phones outside the campus (too) to capture the signal. The jammer is located almost 500 m away from my house, inside a walled compound, but the signal strength inside my room fluctuates too. Sometimes it shows full strength, and the very next moment, it says no signal. Is there anything which I can do about this? If I go two rooms inside and close all the doors, the phone regains signal Anyone know how to make a home made anti signal jammer or something like that?