there is no way to improve signals using app and tweaking combination, try improve signal muna:
tap your device to any material that may serve as metal reflector (ex. screen, roof for higher elevation) tap it well, or use, aluminum foil etc... tap negative (-) terminals to the ground, grounding to the ground (literally) it gives better results .. kahit underground pa location mo
(why? i don't know, mom nature's way.. haha j/k - Grounding is the Key to a better Reception)
then u can start experimenting which app. tweak n setting combination is better.