Currently im using Arudiono sim 900 as my project with a portable battery source. As de picture shown below. I cant let the red light(status) keep it contiuniously. 3 sec after it was on. it blinked out. Any suggestion of what should i do? due to de voltage limit of Arduino i scared of spoiling it by adding more battery.
Not only do you appear to be missing an aerial, you probably need to power the shield independently.